APTD-1364
EVALUATING
TRANSPORTATION CONTROLS
TO REDUCE MOTOR
VEHICLE EMISSIONS IN MAJOR
METROPOLITAN
AREAS
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
-------
APTD-1364
EVALUATING
TRANSPORTATION CONTROLS
TO REDUCE MOTOR VEHICLE
EMISSIONS IN MAJOR
METROPOLITAN AREAS
Prepared by
Institute of Public Administration I
1619 Massachusetts Avenue, N.W.
Washington, D.C. 20036
and
Temekron, Inc.
1619 Massachusetts Avenue, N.W.
Washington, D. C. 20036
In cooperation with
TRW. Inc.
7600 Colshire Drive
McLean, Virginia
EPA Contract No. 68-02-0048
Task Order 6
Proj ect Officer: Gary Hawthorne
Strategy and Air Standards Division
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
Prepared for
ENVIRONMENTAL PROTECTION AGENCY
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
November 1972
-------
The APTD (Air Pollution Technical Data) series of reports is issued by
the Office of Air Programs, Environmental Protection Agency, to report
technical data of interest to a limited number of readers. Copies of
APTD reports are available free of charge to Federal employees, current
contractors and grantees, and non-profit organizations as supp1~es
permit - from the Air Pollution Technical Information Center, EnVIron-
mental Protection Agency, Research Triangle Park, North Carolina 27711
or may be obtained~ for a nominal cost, from the National Technical
Information Service, 5285 Port Royal Road, Springfield, Virginia 22151.
This report was furnished to the Environmental Protection Agency by
the Institute of Public Administration, Teknekron, Inc., and TRW Inc.,
in fulfillment of Contr~ct No. 68-02-0048, Task Order 6. The contents
of. this report are reproduced herein as received from the above men-
tioned contractors. The 9pinions, findings, and conclusions expressed
are those of the author and not necessarily those of the Environmental
Protection Agency.
Office of Air Programs Publication No.
APTD-1364
11
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PREFACE
A number of the Institute of Public Administration's staff
and Consultants contributed to this study, including:
John W.
Hoicka; Donald Infeld; Anna Karavengelos; Sumner Myers; Gilbert
Nelson; Thomas Pogue; Joseph S. Revis; Ralph E. Rechel; Lee H. Rogers;
Helen Scott; Terry Trumbull; and Robert. Witherspoon (froject Director)
Michael Keaton was principal investigator for Teknekron, Inc.
Dianny
Fishman was project Administrative Officer.
...
111
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TABLE OF CONTENTS
INTRODUCTION AND SUMMARY
Purpose and Organization
Study Focus and Working Assumptions
Preliminary Conclusions
Inspection, Maintenance and Retrofit
Gaseous Fuel Systems
Traffic Flow Techniques
Bypassing Thru Traffic
Improvements in Public Transportation
Motor Vehicle Restraints '
'1- '.1.'
Work Schedule Changes
-+
Preliminary Cost Estimates for Public Transport
Operating Costs for Washington, D. C.
Operating Deficit for the United States
CHAPTER 1 -- INSPECTION, MAINTENANCE AND RETROFIT
Definition of Terms
Maintenance Procedures
Retrofit Systems
Air Pollution Control Potential
Necessary
Practicable
Test Regime
Organizational Arrangements
Diagnostic Information
Costs
Manpower Requirements
Implementation Time
Effective
Maximum Feasible Emission Reduction
Inspection and Maintenance
Retrofi t
iv
Improvements
Page
1
1
3
8
16
18
19
21
22
23
26
28
30
32
1-1
1-1
1-2
1-2
1-4
1-4
1-5
1-5
1-8
1-11
1-11
1-13
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1-14
1-19
1-19
1-20
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Institutional Feasibility
Emission and Safety Inspection
Federal Funding
Political Opposition
Local Legal Authority
Administering Agency
Programs
CHAPTER 2 -- GASEOUS FUEL SYSTEMS
Definition of Terms
Liquified Petroleum Gas (LPG)
Natural Gas
Air Pollution Control Potential" '.
Emissions from Gasoline and Gaseous Fueled Vehicles
Maximum Feasible Emission Reduction
Institutional Feasibility
State and Local Safety Regulations
Costs and Risks of Conversion
Legal Authority
CHAPTER 3 -- TRAFFIC FLOW TECHNIQUES
Definition of Terms
Modification of Street
Increases in Effective
Pedestrian Controls
Signalization
Use
Facility Size
Air Pollution Control Potential
Site-Specific Nature of Improvements
Facility Evaluation vs. Network (System)
Annual Traffic Growth
Impact of Traffic Improvements on Speed
Analysis of Recent Research
Application to Six Target Cities
Maximum Feasible Emission Reduction
Institutional Feasibility
v
Evaluation
Page
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1-24
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1-25
1-26
1-27
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2-1
2-2
2-3
2-3
2-4
2-12
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2-18
2-19
2-23
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3-3
3-7
3-7
3-9
3-14
3-14
3-15
3-16
3-22
3-25
3-31
3-32
3-33
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Page
CHAPTER 4 -- BYPASSING THRU TRAFFIC
4-1
Definition of Terms
Circumferential Routes (Beltways)
Inner Loops
Directive Signs and Signals
Special Stickers
Bypass Combined with Motor Vehicle
Restraints
4-1
4-1
4-2
4-3
4-3
4-4
Air Pollution Control Potential
4-8
Maximum'Feasible Emission Reduction
4-12
Institutional Feasibility
4-13
CHAPTER 5 -- IMPROVEMENTS IN PUBLIC TRANSPORTATION
5-1
Definition of Terms
Rapid Transit Systems
Construction of New Systems
Extensions of Existing Systems
Operational and Service Improvements
Bus Systems
Exclusive Bus Lanes
Bus Priority Systems
Operational and Service Improvements
Taxi Systems
Improvements in Taxi Dispatching
Revising Taxi Regulations
Demand-Responsive Systems
Car Pools
People Mov'ers
5-1
5-2
5-3
5-4
5-5
5-7
5-8
5-10
5-11
5-13
5-15
5-17
5-18
5-19
5-24
Air Pollution Control potential
5-25
Maximum Feasible Emission Reduction
5-27
Institutional Feasibility
- Current Position of Public Transport
Rapid Rail Systems
Construction of New Systems
Extensions of Existing Systems
Operational and Service Improvements
Bus Systems
Taxi and Demand-Responsive Systems
Car Pools
People Movers
5-29
-5-2,9'"
5-32
5-32
5-34
5-34
5-36
5-39
5-41
5-42
vi
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CHAPTER 6 -- MOTOR VEHICLE RESTRAINTS
Definition of Terms
Regulating Parking
Pricing Parking
Regulating Road Use
Pricing Road Use
Air Pollution Control Potential
~egulating and Pricing Parking
Regulating and Pricing Road Use
);19.~. Jl,",
Maximum Feasible Emission Reduction
Institutional Feasibility
Regulating Parking
Pricing Parking
Regulating Road Use
Pricing Road Use
.,
, \,'
,,' !
CHAPTER 7 -- WORK SCHEDULE CHANGES
Definition of Terms
Air Pollution Control Potential
Staggering Work Hours
The 4-day Work Week
Maximum Feasible Emission Reduction
Institutional Feasibility
Staggering Work Hours
Feasibility for Employers
Feasibility for Employees
APPENDIX A -- ESTIMATING EMISSION REDUCTIONS FRJM RETROFIT
APPENDIX B -- ESTIMATING EMISSION REDUCTIONS FRCM CONVERSION TO
GASEOUS FUELS
APPENDIX C -- SPEED-EMISSION RELATIONSHIPS
vii
Page
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6-1
6-1
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6-8
6-11
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6-23
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6-26
6-26
7 -1
7 -1
7-3
7-6
7 -12
7-19
7 :-21
7-22
7-23
7-25
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APPENDIX D -- ESTIMATING EMISSION REDUCTIONS FROM TRAFFIC FLOW
TECHNIQUES
APPENDIX E -- ESTDiATING EMISSION REDUCTIONS FROM PU~LIC TRANSPORT
IMPROVEMENTS
APPENDIX F -- ESTIMATING EMISSION REDUCTIONS FROM MOTOR VEHICLE
RESTRAINTS
BIBLIOGRAPHY
..II',
. >C''''
viii
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INDEX OF TABLES
PaJite
Table 1 IMPACT OF TRANSPORTATION CONTROLS ON TRAVEL
PATTERNS AND MOTOR VEHICLE EMISSIONS 9
T~ble 2 1980 INVESTMENT ESTIMATES FOR URBAN TRANSPORT 29
Table 3 BUS TRANSIT ESTTIMATED REVENUES AND EXPENSES FOR
THE WASHINGTON, D.C. REGION, 1969 AND 1975 31
Table 1-1 INSPECTION AND/OR MAINTENANCE PROCEDURES 1-3
Table 1-2 TEST REGIMES 1-7
Table 1-3 ORGANIZATIONAL ARRANGEMENTS FOR ADMINISTERING
INSPECTION PROGRAMS 1-9
Table 2-1 FEDERAL EMISSION STANDARDS FOR LIGHT-DUTY
VEHICLES 2-5
Table 2-2 EXHAUST EMISSION DATA FROM EPA FOR GASEOUS
FUELED VEHICLES 2-6
Table 2-3 EXHAUST EMISSION DATA FROM IGT FOR GASOLINE
FUELED VEHICLES 2-7
Table 2-4 EXHAUST EMISSION DATA FROM IGT FOR GASEOOS
FUELED VEHICLES 2-8
Table 2-5 EXHAUST EMISSION DATA FROM TRW FOR UNCONTROLLED,
CONTROLLED PRE-7l, AND NOx CONTROLLED VEHICLES 2-9
Table 2-6 EXHAUST EMISSION DATA FROM CALIFORNIA ARB FOR
GASEOUS FUELED VEHICLES 2-10
Table 2-7 MAXIMUM FEASIBLE EMISSION REDUCTIONS FROM CON-
VERSION TO GASEOUS FUELS EXPRESSED AS A PER-
CENTAGE OF TOTAL MOTOR VEHICLE EMISSIONS 2-13
Table 2-8 MAXIMUM FEASIBLE EMISSION REDUCTIONS FROM CON-
VERSION TO GASEOUS FUELS EXPRESSED AS A PER-
CENTAGE OF TOTAL AGGREGATE MOTOR VEHICLE
EMISS IONS 2-14
IX
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Table 3-1
Table 3-2
Table 3-3
Table 3-4
Table 3-5
Table 3-6
Table 5-1
Table 6'-1
Table 6-2
Table 6-3
Table 7-1
Table 7-2
Table 7-3
Table 7-4
Table 7-5
Table 7-6
MODIFICATIONS IN STREET USE
nTCREASES IN EFFECTIVE FACILITY SIZE
PEDESTRIAN CONTROLS
"BEFORE" AND "AFTER" SPEEDS FOR SIGNAL PRO-
GRESSION EXPERIMENTS IN NEWARK, NEw JERSEY
SPEED CHANGES FROM TRAFFIC CONTROL EXPERI-
MENTS IN LOUISVILLE, KENTUCKY, & NEWARK,
NEW JERSEY
RANGE OF EXPECTED CHANGES IN SPEED FROM
TRAFFIC FLGl IMPROVEMENTS
VARIETIES OF TAXI SERVICE
MOTOR VEHICLE RESTRAINTS
EFFECT OF TRAFFIC BANS ON CARBON MONOXIDE
CONCENTRATIONS IN TOKYO
WORKERS PARKING THE CBD:
FREE AND PAID
WORK SCHEDULE CHANGES
POSSIBLE ARRANGEMENTS OF A 4-DAY WORK WEEK
DAILY IMPACT OF 4-DAY WORK WEEK ON CONDITIONS
AT A FREEWAY BOTTLENECK
WEEKLY IMPACT OF 4-DAY WORK WEEK ON CONDITIONS
AT A FREEWAY BOTTLENECK
SUMMARY OF SCHEDULE FREEDOM AND STAGGERED
HOURS POTENTIAL BY EMPLOYMENT CLASSIFICATION
PERCENTS OF SAMPLE PREFERRING CHANGED STARTING
TIMES, BY MINUTES OF CHANGE
x
Page
3-4
3-8
3-10
3-23
3-26
3-31
5-14
6-2
6-16
6-24\
7-2
7-13
7-14
7-15
7-26
7 -27
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Figure 1-1
Figure 3-1
Figure 3-2
Figure 3-3
Figure 3-4
Figure 4-1
Figure 7-1
Figure 7-2
Figure 7-3
INDEX OF FIGURES
HYPOTHETICAL DETERIORATION RATES FOR INSPEC-
TION AND MAINTENANCE
DAILY NUMBER OF VEHICLES ENTERING AND LEAVING
THE CENTRAL BUSINESS DISTRICT OF CHICAGO
WASHINGTON, D.C. CORDON COUNTS-POTOMAC RIVER
BRIDGES
FREQUENCY DISTRIBUTION OF PERCENTAGE CHANGE
IN SPEED FROM TRAFFIC FLOW CONTROL EXPERIMENTS
IN LOUISVILLE, KENTUCKY, AND NEWARK, NEW JERSEY
FREQUENCY DISTRIBUTIONS OF PERCENTAGE CHANGE IN
SPEED FROM TRAFFIC FLCM CONTROL EXPERIMENTS IN
LOUISVILLE, KENTUCKY, AND NEWARK, NEW JERSEY
SCHEMATIC REPRESENTATION OF GOTHENBURG, SWEDEN
TRAFFIC RESTRAINT SYSTEM
ESTIMATED PERCENTS OF PEOPLE STARTING WORK IN
MANHATTAN CBD
EFFECTS OF STAGGERED WORK HOURS ON P.M. PAS-
SENGER VOLUMES AT PATH HUDSON TERMINAL
DAILY DEMAND ON L.A. FREEWAY SYSTEM OVER
TIME UNDER SEVERAL 4-DAY WORK WEEK SCHEDULES
XI
Page
1-17
3-17
3-18
3-29
3-30
4-6
7-5
7-9
7-17
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INTRODUCTION AND SUMMARY
The following Interim Report, prepared by the Institute of Public
Administration and Teknekron, Inc., in cooperation with TRW, Inc., pre-
sents preliminary findings from research undertaken for the Office of
Land Use Planning of the Environmental Protection Agency.
The overall ob-
jective of the research is to evaluate transportation controls to reduce
motor vehicle emissions in major metropolitan areas.
Our terms of refer-
ence were to make an appreciation of transportation controls, and to
assess their effectiveness in reducing emissions, their feasibility and
the probable costs.
We were directed to define transportation controls
very broadly. but to give priority to those measures most likely to be
capable of being implemented in the next few years.
Purpose and Organization
The purpose of this Interim Report is to bring together in a pre-
liminary form a description and evaluation of those transportation con-
troIs which could conceivably reduce motor vehicle emissions in the next
few years.
In the course of our researches, we have reviewed~he relevant
transportation literature, as well as more recent works which specifically
address the use of transportation controls to reduce motor vehicle emis-
sions (see bibliography attached to this report).
We have also attempted to
summarize new evidence which is pertinent (e.g., recent research on traffic
flow improvements on a network-wide basis, demonstrations to date of public
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- 2 -
transport improvements, accumulated experience with vehicle-free zones)
much of which has not appeared previously in print.
Under the Clean Air Act amendments of 1970 and subsequent action
by the EPA Administrator, state implementation plans for meeting national
ambient air standards must be submitted to EPA by February of 1972.
In
many cases, meeting national ambient air standards will require transporta-
tion controls.
The intent of this Interim Report is to provide assistance
in the preparation of transportation components of state plans.
Given the scope of the study described above, it may be convenient
to indicate how this Interim Report is organized.
Briefly, it consists
of an Introduction and Summary statement, followed by seven chapters,
each dealing with a different transportation control.
The chapters in
order of presentation are:
Inspection, Maintenance and Retrofit; Gaseous
Fuel Systems; Traffic Flow Techniques; Bypassing Thru Traffic; Improve-
ments in Public Transportation; Motor Vehicle Restraints and Work Schedule
Changes.
Each chapter consists of a section defining and describing the
measures considered, an analysis of the air pollution control potential
(including an estimate of the maximum feasible emission reductions which
would be possible) and a discussion of institutional feasibility (includ-
ing probable costs).
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- 3 -
Study Focus and Working Assumptions
Before proceeding, the focus for the study (of which this Interim
Report is part) as well as our working assumptions should be noted.
In
many cases, exclusions or simplifying assumptions have had to be made so
that the subject matter left, while large and complex, is nevertheless
coherent and manageable.
In order to focus the study, we have been asked to give priority
to -those transportation controls capable of being introduced by 1977 to
reduce carbon monoxide emissions from light duty motor vehicles in and
around high pollution areas of large metropolitan regions.
Each of these
terms of reference is taken up in turn.
Focusing upon transportation controls capable of implementation
(and, by implication, impact) by 1977, it should be stressed, precludes
consideration of many measures which hold out the potential fOl reducing
emissions, but over a longer term.
For example, the 1977 time frame rules
out major new highway construction (e.g., circumferential routes to bypass
through traffic away from central city areas), the provision of new rapid
rail systems (except those already under construction, i.e., San Francisco's
BART and Washington, D.C.'s Metro).
The same time frame also precludes
most land-use controls (e.g., modification of zoning regulations respect-
ing new office construction so as to limit total parking space, a measure
which would require at least a decade to have an appreciable impact on
air quality).
We have considered many of these medium and long-term controls
in passing, and have attempted to draw attention to the longer run consequences,
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- 4 -
We have not been able to discuss them in detail because of the sport
time frame (in effect, the next five years) of this study.
Primary concern with carbon monoxide emissions, it should be em-
phasized, is not to the exclusion of other vehicle emissions (e.g., hydro-
carbons and nitrogen oxides).
Trade-offs among pollutants (e.g., the
possibility that increased vehicle speeds reduce carbon monoxide but ma.
increase nitrpgen oxides) have been kept in mind throughout.
The focus of this study is on "light duty vehicles," as defined
1
by EPA.
Generally stated, this category comprises commercial vehicles
with a rating of up to 6,000 pounds GVW, or passenger vehicles with occu-
pancy of up to 12 persons.
Time did not permit detailed consideration of
trucks, their contribution to traffic congestion and accompanying air pollu-
tion and various truck-specific transportation controls.
While trucks may
account for a high proportion of carbon monoxide emissions in some down-
town areas (Manhattan is an extreme case), more generally they represent
only a small proportion of typical traffic streams.
The main problem is
that the usual travel pattern of trucks, involving frequent stops and park-
ing, tends to tie up traffic and thus compound congestion and air pollu-
tion.
Among the many control possibilities that could be studied are:
regular inspection and maintenance, the establishment of special truck
1. Federal Register, XXXVI, No. 228, Nov. 25, 1971, p. 22449. GVW
refers to gross vehicle weight, meaning the manufacturer's gross weight
rating for the individual vehicle. This EPA definition, it should be
noted, differs from the Department of Commerce classification of light
duty vehicles to encompass any vehicle with a gross vehicl~ weight of
10,000 pounds or less.
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- 5
routes, provision of improved loading facilities, and a modification of
pick-up-and-de1ivery hours.
For this report, we have also focused on automobile air pollution
problems arising primarily from travel into, out of and within central
cities, and particularly the central business district (CBD)l during the
peak or rush hours on the mornings and afternoons of workdays.
In most
cities these movements are apparently the greatest contributors to conges-
tion and motor vehicle emissions.
Trips at other times of the day or week
can create significant air pollution problems, but these are almost always
of second-order importance.
Furthermore, in most cities it is apparently
in these core areas (e.g., the CBD) that daytime population densities (and
hence exposures to air pollution) are greatest.
This generalization, how-
ever,
does not hold good for metropolitan areas where highly dispersed
travel patterns tend to spread motor vehicle emission relatively uniform-
1y throughout the area.
Los Angeles provides a good example.
Finally, the study concentrates on large metropolitan areas, with
specific reference to six central cities:
Chicago, Denver, Los Angeles,
New York City, San Francisco and Washington, D.C.
Illustrative data from
some of these cities (and particularly Washington, D.C.) are provided in
this Int&~im Report~2
In general, however, the conclusions drawn in
1. Central cities are usually defined as those areas within the incor-
porated limits of the major city in any metropolitan area. Definitions of
CBD's vary widely, but generally refer to the high density commercial and
business cores of cities.
2. Additional data acquisition and interviews in the field are planned
for each city in subsequent stages of this study.
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6 -
the present document are thought to be valid for most large metropolitan
areas.
In addition to the above study focus, we have taken as the basis
for this Interim Report several working assumptions.
First, we were asked
to assume that motor vehicle manufacturers will meet the federal new car
emission standards for carbon monoxide by 1975.
At this writing, however,
it is by no means clear that appropriate exhaust control systems will be
1
available to meet the deadline imposed by Congress.
Furthermore, even if
exhaust control systems are developed by the deadline to meet new car
emission standards, these systems may be highly unreliable.
These in-
herent uncertainties as to the availability and reliability of new systems,
argue strongly for contingency planning, an argument that is reinforced
by other considerations.
For example, it may well be that the increased
cost of a vehicle arising from pollution control and safety equipment
will discourage the replacement of old vehicles.
Also, it should be
realized that as Americans depend increasingly upon the automobile as
a way of life, more and more vehicles are going to be in circulation.
Many of the measures discussed in this Interim Report can act as useful
supplements to federal new car emission standards, all the more so if
enforcement of emission standards is less effective than hoped for.
1. In a recent study for EPA, the National Academy of Sciences reported
that the requisite technology to meet clean-air requirements is lagging
and suggested that the 1975-76 deadlines be extended by one year. See
National Academy of Sciences, Committee on Motor Vehicle Emissions,
Semi-Annual Report to the Environmental Protection Agency (Washington,
D.C.: National Academy of Sciences, January 1972).
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Second, we have assumed that significant reductions in person trips
into and around central cities cannot be accomplished without radical
changed in land-use patterns (i.e., in residential and commercial locations).
1
To achieve these changes would take at least two to three decades.
In
the short term, reductions in vehicle miles traveled (not person trips)
may be accomplished through diversion of motor vehicle trips to public
2
transportation.
However, even modest diversions would require important
improv~ents in public transportation to enable trips to be made.
Third, we have assumed that any improvement in the comfort and con-
venience of trips, or a reduction in travel times, will generate additional
trips which would not have been forecast as part of the long-term growth.
At the present time, the precise reasons for making these additional trips
are not well understood, although available evidence and the observations
of experienced transportation analysts all tend to support this, assumption. 3
1. Implementation of some of the transportation controls discussed in
this Interim Report may have a very minor impact on land use by 1977,
probably through a small redistribution of origins and destinations.
2. Public
elude mass
as well as
responsive
transportation had been broadly defined for this report to in-
transit as conventionally defined (rapid rail and bus systems),
a number of other means of conveyance such as taxi, demand-
systems, car pools and people movers.
3. For details, see Chapter 3, section on "Annual Traffic Growth."
Because the dynamics of long-term and induced travel are not well under-
stood, we have used a range of reasonable assumptions in estimating
potential emission reductions, as elaborated in Appendix D.
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Preltminary Conclusions
This report is the result of a six-month study of a large, complex
subject.
Most of the transportation controls examined have been considered
only recently for purposes of air pollution control.
Accordingly, con-
elusions can be only tentative at this stage.
However, at this point in
the study our main conclusions are:
1.
In most of the metropolitan areas under stud~overall
emission reductions of at least 50 percent from existing
levels appear required to meet the national ambient air
standards for carbon monoxide by 1975,
These required re-
ductions are substantially higher in some central city
areas (e.g., 80 percent in Midtown Manhattan).l
2.
Measured against this scale, most transportation controls
that are capable of being introduced in the next few years
offer the potential for only modest reductions.
Details are
summarized in Table 1.
3.
Even those controls which are easiest to implement will
take several years to develop and put into effect.
All con-
troIs would entail very substantial implementation costs
(although in some cases, such as an increase in parking rates,
these costs could be recouped from revenue). 2
1. Unless otherwise noted, "emissions" or "emission reductions" refer to
carbon monoxide throughout this report.
2. Preliminary cost estimates for improving public transportation are pro.
vided in the concluding section of this Introduction and Summary.
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Table 1
IMPACT OF TRANSPORTATION CONTROLS ON
TRAVEL PATTERNS AND MOTOR VEHICLE EMISSIONS
(CARBON MONOXIDE FROM LIGHT DUTY MOTOR VEHICLES ONLY)
Transportation
Control Candidates
Impact on 1
Travel Patterns
Impact on 2
Motor Vehicle Emissions
Inspection, Main-
tenance and Retro-
fit
No changes in modal mix,
trip generation or ori-
gin-destination patterns.
'"'
~
~
m
~
~
I
~
'-'
Gaseous Fuel Systems
No changes in modal mix,
trip generation or origin-
destination patterns.
i
~
H
~
o
~
3
10 to 25 percent.
Upper range (particular-
ly 20 to 25 percent) de-
cidedly less likely than
lower range (particularly
10 percent).
4
Less than 15 percent.
Appropriate only for large,
centrally-maintained fleets
which account for a rela-
tively high proportion of
total vehicle miles trav-
eled (e.g., taxicabs in
Borough of Manhattan).
1. Transportation controls are arranged in order of increasing impact upon
travel patterns, and hence upon social and economic activity and location
of land use. To the extent that these impacts imply increasing social
and economic dislocation, each successive transportation control would need
correspondingly longer lead times to implement and take effect.
2. Expressed as percent of emissions attributable to light duty motor ve-
hicles. Highest values are estimates of maximum feasible emission reduc-
tions, using data from central cities where control in question appears to
have greatest potential for reducing emissions. It is extremely unlikely
that any city could achieve maximum reduction from each of controls. Lower
values do not represent minimum emission reduction, but rather an estimate
based upon~derately favorable conditions. Estimates for improvements in
public transportation, motor vehicle restraints and work schedule changes
assume a reduction in motor vehicle miles traveled results in equivalent
reduction in motor vehicle emissions. All estimates are for initial reduc-
tions and do not take into account deterioration (e.g., deterioration of
control devices due to accumulation of mileage).
3. Estimates for inspection and maintenance only.
Appendix A for further discussion.
See Chapter land
4. Estimates for simple conversion from gasoline to LPG or ~Rt~~'al gas.
See Chapter 2 and Appendix B for further discussion.
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10 -
Table 1
(page 2 of 4)
IMPACT OF TRANSPORTATION CONTROLS ON
TRAVEL PATTERNS AND MOTOR VEHICLE EMISSIONS
(CARBON MONOXIDE FROM LIGHT DUTY MOTOR VEHICLES ONLY)
Transportation
Control Candidates
Impact on
Travel Patterns
Impact on
Motor Vehicle Emissions
Traffic Flow
Techniques
No changes in modal mix.
Possible increase in
trip generation as a re-
sult of improvements in
traffic flow. No changes
in origin-destination
patterns, at least for
the short term.
........
en
I-<
!13
-.
Lf"I
I
N
'-'
s
~
H
~
g
UJ
Bypassing Thru
Traffic
No changes in modal mix.
Possible increase in
trip generation as a re-
sult of improvements in
traffic flow. No changes
in origin-destination
patterns, at least for
the short term.
1
Less than 20 percent.
However, emissions appear
to decrease for only the
year immediately follow-
ing implementation, after
which time emissions may
increase above original
levels du~growth in
traffic volumes. To con-
trol traffic volumes,
motor vehicle restraints
would be required.
2
Less than 5 percent.
Measures requiring new
construction (e.g., cir-
cumferential routes) not
implementable within five
years. Modest bypassing
may be possible through
use of directive signs
and/or signals. More sub-
stantial bypassing will
require motor vehicle
restraints.
1. Based on illustrative example assuming a 30 percent increase in network-
wide average vehicle speed. See Chapter 3 and Appendices C and D for further
discussion.
2. Estimates for traffic which could be bypassed away from central cities
as a result of improvments capable of implementation in the short term,
but in the absence of motor vehicle restraints. See Chapter 4 for further
di scussion.
-------
- 11 -
Table 1
(page 3 of 4)
IMPACT OF TRANSPORTATION CONTROLS ON
TRAVEL PATTERNS AND MOTOR VEHICLE EMISSIONS
(CARBON MONOXIDE FROM LIGHT DUTY MOTOR VEHICLES ONLY)
Transportation
Control Candidates
Impact on
Travel Patterns
Impact on
Motor Vehicle Emissions
Improvements in
Public Transportation
Changes in modal mix by
improvements in public
transport; no change in
trip generation or ori-
gin-destination patterns
at least in the short
term.
-
(/)
~
lIS
Q)
>.
o
.-I
I
U"\
'-"
~
~
~
Motor Vehicle
Restraints
Changes in modal mix by
improvements in public
transport and motor
vehicle restraints. Only
minor changes in trip
generation, or origin-
destination patterns at
least in the short term.
~
H
~
~
1
Less than 5 percent.
Improvements in public
transport are a necessary
but not sufficient condi-
dition for reducing motor
vehicle emissions. To
have an appreciable effect
on emissions public trans-
port improvements must be
combined with motor vehi-
cle restraints. Restrain-
ing or restricting motor
vehicles, however, would
require substantial pub-
lic transport improve-
ments to provide an alter-
nate means of making trips.
2
5 to 25 percent.
Potential emission reduc-
tions depend upon the
severity of restraints.
Several motor vehicle
restraints are administra-
tively feasible. However,
the mechanics of imposing
motor vehicle restraints
are much less of a problem
than gaining public accept-
ance to limit "freedom of
the road."
1. Estimates for public transportation broadly defined to include mass
transit (rapid rail and bus systems) as well as other means of conveyance,
such as taxi, demand-responsive systems, car pools and people movers.
Estimates are for reductions in traffic in the absence of motor vehicle
restraints. See Chapter 5 and Appendix E for further discussion.
2. Lower estimates are for doubling downtown parking rates. Higher es-
timates are for tripling or for quadrupling downtown parking rates, depend-
ing upon comprehensiveness of parking control program. See Chapter 6 and
Appendix F for further discussion.
-------
- 12 -
Table 1
(page 4 of 4)
IMPACT OF TRANSPORTATION CONTROLS ON
TRAVEL PATTERNS AND MOTOR VEHICLE EMISSIONS
(CARBON MONOXIDE FROM LIGHT DUTY MOTOR VEHICLES ONLY)
Transportation
Control Candidates
Impact on
Travel Patterns
Impact on
Motor Vehicle Emissions
Work Schedule
Changes
Changes in modal mix,
possible reduction in
trip generation (par-
ticularly for the jour-
ney to work) and changes
in origin-destination
patterns due to addi-
tional recreational
trips.
~
00
~
~
~
~
o
N
I
o
~
'-'
~
~
H
o
~
~
2
Land Use Controls
Change in modal mix;
change in origin-desti-
nation patterns; change
in trip generation.
1
Less than 3 percent.
Work trips would be re-
duced but increased lei-
sure time would probably
generate additional rec-
reational trips (although
these are likely to be
primarily at off-peak
periods to and from areas
outside the central city).
Could not be implemented
with any appreciable
effect on emissions in
the short term. Medium
and long term effects
not known.
1. Estimates are for 4-day week, with working days spread over six days,
assuming 30 percent of vehicle miles traveled are accounted for by the
journey to work and a maximum of 25 percent of the labor force on 4-day
week by 1977. See Chapter 7 for further discussion.
, '.', -. -, - ,-.,..., "1,':'--
2. For example, public policy could encourage land use patterns which would
minimize distances between home and work, home and school, and home and shops.
In addition, residential and commercial development could be promoted around
existing rail and bus lines (and such systems extended) so that public trans-
port would be more accessible to a larger portion of the metropolitan popula-
tion.
-------
- 13 -
It should be stressed that, absent more empirical data and computer
simulation, the above estimates must be considered as rough approximations
only.
As noted in Table 1, estimates are expressed as a percentage of
carbon monoxide emissions attributable to light duty motor vehicles (see
EPA definition given earlier).
To the extent that carbon monoxide emissions
in any area are caused by heavy duty vehicles (e.g., buses or trucks) or
by stationary sources (e.g., space heating), overall emission reductions
would be less than estimated here.
The proportionate contribution from
these sources, of course, must be determined on a city-by-city basis using
an emissions inventory for each area.
As also noted in Table 1, estimates are for initial emission reduc-
accumulation of mileage.
tions and do not take into account deterioration of control devices due to
For reasons indicated e1sewhere1 reliable data
on deterioration are not available at this time.
However, using a hypo-
thetica1 example, if maintained motor vehicles return to their pre-main-
tained emission levels within six months, the emission reduction from an
annual inspection and maintenance program would be only one-half of the
values estimated above.
An additional difficulty is that some transportation controls (no-
tab1y motor vehicle restraints) could have additive effects by both re-
ducing vehicle miles traveled and improving traffic flows.
Even if
1.
See Chapters 1 and 2, sections on "Air Pollution Control PotentiaL II
-------
- 14 !..
1 dd. .
emissions-speed relationships were known with confidence, these a ~t~ve
effects cannot be estimated on a network-wide basis without computer simu-
2
lation.
Nevertheless, it does appear that the additive effects of motor
vehicle restraints would result in substantially greater emission reduc-
3
tions than estimated above.
This potential, along with the limited effec-
tiveness of other transportation controls, indicate that vehicle restraints
would be required in many major metropolitan areas (such as the six under
study) to reach and maintain national ambient air standards for carbon
monoxide by 1975.
In addition, motor vehicle restraints would have to be
accompanied by important improvements in public transport if serious social
and economic repercussions are to be avoided.
1. Although empirical data are extremely limited, it is usually assumed
that emissions (carbon monoxide and hydrocarbons) are lower in freely
flowing traffic than in congested stop-and-go conditions. There is some
evidence that the converse holds for nitrogen oxides (i.e., that NO
emissions increase with higher vehicle speeds). Available researchxand
some complicating technical considerations are treated in Appendix C to
this report.
2. Using computer simulation, controls could be tested for groups of
intersections for the network as a whole, taking into account data on
street geometry, vehicle speeds, turning percentages at each intersection,
existing signalization and so forth.
3. We did develop an example to illustrate this principle. Under one
set of assumptions (see Appendix D, section on "Reducing Traffic Volumes
with Motor Vehicle Restraints" for details), implementation of a motor
vehicle restraint program capable of restraining traffic volumes on an
urban arterial could reduce emissions b~ more than 50 percent.
-------
- 15 -
Assuming substantially improved public transport, the imp1ernenta-
h. 1 . 1
tion of some forms of motor ve ~c e restra~nts would appear technically
feasible within five years.
However, the basic question these measures
raise is the extent to which it is politically possible to deprive people
of some of the convenience of their cars in return for cleaner air.
Furthermore, changes in prevailing travel patterns (e.g., cOmIDuta-
tion by private passenger car) and the provision of public transport cannot
be brought about over night.
Since the automobile is intricately related
2
to almost all aspects of community life,
the social and economic conse-
quences of changing these established relationships are likely to be pro-
found.
We conclude that for motor vehicle restraints to be recommended,
it would be desirable to consider them as more than simply short term
3
measures for air pollution control alone.
Motor vehicle restraints may be
1. For example, parking controls, toll collection, or a congestion pass
approach. There is already good evidence in many European and Japanese
cities that motor vehicle restraints are feasible, at least on a limited
scale; these restraints have also proven highly effective in reducing
localized carbon monoxide concentrations.
2. For example, in addition to passenger movement, motor vehicles in
central cities are relied upon extensively to provide for the delivery
of goods, ernerg~cy services (e.g., police and fire), mail distribution
and pick-up, maintenance work on public utilities and a multitude of other
essential services.
3. It should also be pointed out that, since the transportation controls
discussed in this report all involve substantial implementation costs and/or
significant changes in travel patterns, and can take effect only over an
extended period of time, they are not appropriate for intermittent applica-
tion.
-------
- 16 -
1
warranted over a longer term and on other grounds (e.g., reducing noise
and relieving congestion) in addition to air pollution control.
suggests the desirability of evaluating motor vehicle restraints (as well
This
as some of the other more promising transportation controls considered in
this report) within a broader context and a longer time frame than has been
the objective of this study.
In addition to the above, we have arrived at the following conclu-
sions concerning each transportation control.
Inspection, Maintenance and Retrofit
At the present time, enforcement of federal new car emission stan-
dards is the principal public policy to control motor vehicle emissions.
Its effectiveness depends upon in-use vehicle conformance (i.e., mileage
accumulation without a substantial deterioration of exhaust control sys-
2
terns ).
Under the Federal Clean Air Act, authority to regulate emissions
from in-use motor vehicles is retained by state and local governments;
however, states are required to provide for periodic inspection and test-
ing of in-use vehicles to the extent "necessary and practicable."
The
same legislation also authorizes federal funding for "effective" inspec-
tion, maintenance and retrofit programs.
Preliminary indications are that regulation of. i.n-use vehicle.
emissions will be necessary in several large metropolitan areas to meet
1. For example, a number of considerations noted earlier argue strongly
for contingency planning in the event that efforts to control emissions
at the source should fall short. Motor vehicle restraints could constitute
an important component of contingency plans.
2. The ability of auto manufacturers to assure quality control of exhaust
emission control systems in assembly-line vehicles will be important so as
to ensure that these do not deviate substantially from the sample vehicles
tested by the Federal government.
-------
- 17 -
national ambient air quality standards.
But the practicability and
effectiveness of inspection, maintenance and retrofit cannot be precisely
1
established at this time.
Estimating the effectiveness over time of inspection, maintenance
and retrofit is impossible at present, due to imperfect information (e.g.,
,
respecting deterioration of maintained vehicles between inspections) and
inherent uncertainties (e.g., as to post-1975 exhaust control systems).
Acquiring additional information will probably take another 12 to 18
months for experimentation in pilot projects.
These lead times imply that
most federally funded inspection, maintenance and retrofit programs will
probably not be in place until at least 1975.
Absent this information, it is nevertheless possible to arrive at
a rather broad range of initial emission reductions which can reasonably
be expected.
The most likely initial reductions from inspection and main-
tenance (as applied to the light duty motor vehicle population) would be
on the order of 10 to 25 percent.
Values in the upper range (particularly
20 or 25 percent) are decidedly less likely than those in the lower range
(particularly 10 percent).
Deterioration of maintained vehicles (in the
1. Implicit in the notion of practicability are considerations as to
test regimes, organizational arrangements, diagnostic information, costs,
manpower requirements, and implementation times. Many of these considera-
tions are complex and highly technical, and cannot be resolved until com-
pletion of several investigations currently being conducted under EPA
sponsorship. Preliminary data are expected to be available in 1972. The
major issues requiring resolution are set forth in Chapter 1, and where
possible, tentative conclusions are drawn on the basis of existing
evidence.
-------
- 18 -
interval between inspections) would lessen the effectiveness of this
1
control.
"
With respect to retrofit, currently available "industry type
devices appear able to reduce emissions by 20 to 25 percent for pre-
controlled vehicles.
For a number of reasons, however, these reductions
are much more modest when applied to the light duty vehicle population
2
as a whole.
We conclude that retrofit does not warrant furth~r con-
sideration as a control with widespread application.
Gaseous Fuel Systems
Conversion of gasoline-powered motor vehicles to gaseous fuels
(liquified petroleum gas or natural gas) should be considered only for
large centrally maintained fleets which account for a high proportion
3
of total vehicle miles traveled and operate in severely polluted areas.
Medallion taxicabs in the Borough of Manhattan are one such example.
Emission reductions achievable through conversion to gaseous fuels are
highly variable.
However, for pre-l975 motor vehicles significant reduc-
tions in carbon monoxide and hydrocarbon emissions and some reduction in
nitrogen oxide emissions can be expected.
1. For example, should an inspection and maintenance program be im-
plemented, and the average vehicle be returned to original (i.e., pre-
maintained) condition after six months, the annual air pollution control
potential of the program would be only half of the values indicated
above.
2.
For details see Chapter 1 and Appendix A.
3. For reasons discussed
version (i.e., conversion
exhaust gas recirculation
catlytic converters).
in Chapter 2, we have examined only simple con-
which does not include modification such as
or the addition of thermal reactors and/or
-------
- 19 -
New car federal emission standards for 1975 and beyond are below
levels which can be achieved through simple conversion.
Consequently,
conversion would be an interim measure, assuming 1975 emission standards
1
are achieved.
Diversion of natural gas from power production or space
heating to motor vehicle use would be counter-productive from a pollu-
tion abatement point of view.
Implementation problems 100m large even for the limited case of
converting fleet vehicles.
Specific economic and/or regulatory incen-
tives would be required to induce fleet owners to convert to gaseous
fuels, in view of the capital investments required, the logistics of
fuel supply, reduced drivability, new maintenance requirements, and the
loss of manufacturers' warranties implicit in conversion.
Traffic Flow Techniques
Traffic flow techniques can be implemented to reduce congestion,
2
thus smoothing traffic flow and increasing average vehicle speeds.
When carefully designed and implemented to take network repercussions
into account, these techniques (e.g., improved signalization, channeli-
zation, exclusive left turn lanes and others) can have significant
impacts on speed.
A review of recently available "Before" and "After" results
of traffic flow experiments carried out in Louisville and Newark
1. That is, federal new car emission standards for 1975 and after require
more stringent control than appears possible with simple conversion.
2. As noted earlier, however, there is some evidence that NOx emissions
increase with increased vehicle speeds. Consequently, consideration of
traffic flow techniques requires careful evaluation of pollutant trade-
offs (e.g., less CO but more NOX) especially in those areas (e.g., Los
Angeles) Where nitrogen oxides appear to be the primary problem.
-------
- 20 -
reveals that, of the 43 instances in Which average travel speeds in-
creased after implementation of traffic flow techniques, approximately
two-thirds of the speed improvements fell between the class intervals
5-10 percent at the lower bound and 35-40 percent at the upper bound.
The median speed increased from 13.6 to 17.3 mph, a 27.6 percent increase.
Assuming an increase in average vehicle speed along an urban ar-
teria1 of from 10 to 15 mph, emissions could be reduced by about 20 per-
cent.
At best, however, these emission reductions would seem short lived
(no more than one year under most assumPtions1).
At worst, emissions
could be significantly greater than if no "improvements" had been imp1e-
mented at alL
We conclude that traffic flow techniques -- unless accompanied
by motor vehicle restraints -- could well be counter-productive from
an air pollution control point of view.
Furthermore, many traffic flow
techniques would render public transport (especially bus) less attractive
relative to the automobi1e.2
Finally, implementation of traffic flow
1. For details see Appendix D. Estimating emission reductions from
traffic flow techniques must take into account both higher average speeds
(which reduce emissions) and higher vehicle volumes (which increase
emissions). Lower emissions from higher average speeds can be quickly
overwhelmed by additional emissions from greater vehicular volumes (caused
by normal long-term traffic growth and "induced" traffic resulting from
improved conditions). To illustrate these possibilities, we developed a
number of assumptions about long-term induced traffic growth. It should
be emphasized, however, that increases in vehicle volumes are highly
variable, depending upon existing "capacity saturation" and local travel
trends.
2. An important exception concerns bus priority systems, discussed in
Chapter 5.
-------
- 21 -
improvements on a network wide basis would be a costly measure, par-
ticularly when weighted against the ephemeral effectiveness of these
controls.
Bypassing Thru Traffic
In large central cities (such as the s~x under study) thru traffic
can account for about 5 to 20 percent ~f total traffic volumes, even at
peak hours.
From an air pollution control viewpoint, bypassing thru
traffic would (1) shift vehicle mile~ traveled away from already con-
gested central city roadways and (2) smooth traffic flows by a separa-
tion of thru and local traffic in the areas affected.
Both results would
reduce emissions in high pollution areas of the central. city, the first
by redistributing emissions elsewhere, the second by bringing higher
average vehicle speeds, fewer stops and starts and idling and the emission
reductions associated with these improvements.
Several possibilities are available to bypass thru traffic, includ-
ing the use of circumferential routes (e.g., beltways). inner city
barriers (e.g., as in Gothenburg, Sweden), and directive signs or sig-
nals.
To the extent that these measures depend upon new construction,
they cannot be implemented within the next five years; 'to the extent
that other measures (e.g., directive signs and/or signals) are used and
are designed specifically to attract and divert vehicles away from cen-
tral cities, some emission reduction may occur.
Our best judgment is
that the reductions which could be achieved in the short term (i.e.,
within five years) would not exceed 5 percent for most central cities.
More substantial reductions would require motor vehicle restraints
-------
- 22 -
(e.g., through toll collection) to discourage thru trips.
Given the
substantial share of thru traffic in some central city areas (a third
or more of total traffic is typical in the CBD), this possibility
appears to merit more attention than it is now receiving.
Improvements in Public Transportation
Reducing motor vehicle emissions implies a modal diversion from
private passenger cars to public transport.
However, extensive review
of recent experience with public transport improvements reveals that
these improvements alone hold little promise for attracting motorists
out of their automobiles.l
Modal diversion to public transport, more-
over, does not necessarily reduce motor vehicle traffic.
Of all public
transport improvements in recent years, the Philadelphia-Lindenwold
line has often been cited as a great modal diversion success.
However,
special analysis undertaken as part of this study did not establish that
any reduction in motor vehicle traffic had occurred.
We conclude that public transport improvements alone hold out
little promise for major modal diversions, much less a reduction in
motor vehicle emissions.
Our best judgment is that even extensive
1. There are no prospects at all for displacing motorists to public
transport by minor improvements dr renewal of equipment. Only an all-
out marketing effort, complete with variable scheduling and great in-
creases in express services, can even hold present levels of public
transport traffic. The few public transport success stories of recent
years have been carefully marketed efforts that meet specific consumer
needs and operate nearly door-to-door at nearly private passenger car
speeds. People have demonstrated their willingness to pay higher fares
for these services.
-------
- 23 -
1
improvements would be unlikely to reduce vehicle miles traveled (and
hence emissions) by more than 5 percent in any major metropolitan area.
Improvements in public transport, therefore, are a necessary but
not sufficient condition for reducing motor veh~cle emissions.
They are
necessary because reducing motor vehicle use in high pollution areas will
require substantially improved public transport to provide an alternative
2
means of making trips.
They are not sufficient, however, since public
transport improvements, unaccompanied by motor vehicle restraints.
will reduce motor vehicle traffic only modestly, if at all.
Indeed,
as a result of some improvements (especially rapid rail) emissions may
actually increase where they are currently worst, in the downtown and
3
other densely developed areas.
Motor Vehicle Restraints
For many transportation controls (i.e., traffic flow techniques,
bypassing thru traffic and improvements in public transportation) to be
effective, motor vehicle restraints will be required.
These restraints
1. Reference is to vehicle miles traveled by light duty vehicles (e.g.,
the private passenger car).
2. In no U.S. metropolitan area at present is there public transport
which is capable of satisfying all trip-making needs, even in the CBD.
To meet these needs, expansion of existing taxi service and the intro-
duction of demand-responsive systems (e.g., dial-a-ride) appear the most
promising. Shared rides on these systems would probably not reduce work
trip traffic significantly, but could cut down on the growing use of
second cars.
3. This suggests that
with implementation of
Washington, D. C.
EPA should monitor the possibility, particularly
new rapid rail systems in San Francisco and
-------
- 24 -
could consist of parking regulations or the imposition of higher park-
ing prices, the regulation of road use (e.g., pedestrian malls or vehicle
free zones) or road pricing (e.g., toll collection or the use of a con-
gestion pass in high pollution areas).
None of these measures will be
politically popular, and intense opposition can be expected from those
whose direct interests are involved (road users, automobile owners as so-
ciations, downtown businessmen, parking garage owners and others).
This suggests that for motor vehicle restraints to be at all
acceptable to the public (and hence workable and effective), the quality
and quantity of public transport must be importantly and visibly im-
proved.
Improvements should be made in conjunction with any strategy to
reduce motor vehicle use.
The most promising restraint, at least for the short term, would
be to intensify control over the location, amount and use of parking
space, both on- and off-street.
The most desirable method of control
appears to be through municipal taxation, particularly where local
revenues will be required for improved and expanded public transport.
The effectiveness of parking controls, however, will be limited by
several factors.
First, thru traffic and internal circulation will not
be affected; indeed it would probably be encouraged if a lower volume
of local traffic results from parking controls in some areas.
Second,
comprehensive parking controls, particularly over already existing
space provided by private firms and governme?t agencies, would be diffi-
cult to enforce and would probably require new legislation.
In many
downtown areas, such space constitutes more than half of existing storage
capacity.
-------
- 25 -
To the extent that it is practical, road pricing would be a more
effective motor vehicle restraint for purposes of air pollution control.
This potential (as well as other ancillary benefits) argues strongly for
further exploration of the concept to determirie'whether and how such a
system could be implemented.
Some measures '(e.g., toll collection or a
congestion pass approach) show promise.'f()r'near-term application, although
substantial increases in enforcement m~y~be required.
The mechanics of
imposing these controls, however, are less of a problem than gaining public
acceptance to limit "freedom of the road" in areas of high air pollution. 1
If motor vehicle restraints are to be effective, dramatic departures
from previous practice would appear necessary (e.g., tripling or quadrup-
ling parking rates for many areas of the city or tolling off major por-
tions of the downtown).
Restraints this severe could cause profound
social, economic and land-use effects, many of which may be highly un-
desirable from other standpoints.
For example, severe motor vehicle
restraints in some areas of the central city could cause (1) employment
centers to shift to the suburbs, (2) an undermining of the city prop-
erty tax base, and (3) particularly adverse economic effects on low in-
come residents.
The effectiveness of these measures, of course, will depend on
the severity of restraints.
Our best judgment is that the doubling of
1. The feasibility of these measures will vary widely in different
metropolitan areas, depending on such factors a,s the geography of the
city, the size of the central area, the availability of public trans-
port, the shape of the street network, the urgency of the local air
pollution problem, and -- probably most importantly -- the local atti-
tudes toward air pollution control and the degree to which public
officials are willing to propose politically unpalatable measures to
achieve air pollution control.
-------
- 26 -
parking rates (here taken as a surrogate for motor vehicle restraints)
would have little effect.
However, if a comprehensive parking control
program were implemented (i.e., a parking space tax of $60.00 to $80.00
per month were applied, all on-street parking were eliminated, and pro-
hibition of illegal parking were strictly enforced), in a city such as
Washington, D.C.,an overa11~~duction in motor vehicle traffic of per-
haps 20 percent, or at the most, 25 percent, might be achieved.
~his assumes, of course, that public transport services would be sub-
All
stantia1ly improved.
In Washington,
D. C.,
this would entail tripling
or quadrupling existing rates to $90.00 to $120.00 per month for present
pay parking, and imposing $60.00 to $80.00 per month rates for present
free parking.
These increases would appear to represent the upper
limit of action at the present time.
Work Schedule Changes
Recent experience with work schedule changes in the United States
and abroad suggest that these measures are feasible.
Two measures for
changing work schedules were considered: work staggering and the 4-day
1
week.
1. Work staggering involves making small systematic shifts in work
hours of employees so that currently under-utilized travel times to
the CBD are more adequately used. Conceivably, this could result in
decreased peak hour congestion, and higher average vehicle speeds --
and reduced emissions. The 4-day work week has the same potential
effect: since the work week is shortened, each work day will be length-
ened and thus "out of phase" with traditional peak hours (at least at
one of the peaks). Moreover, and much more importantly for air pollu-
tion control, the 4-day week would reduce the weekly journey to work
trips of those affected by 20 percent.
-------
- 27 -
Of the two measures, the 4-day week goes further towards reduc-
ing motor vehicle emissions than staggered hours because it cuts weekly
commuting trips by a fifth and shifts those workers involved away from
peak hour travel.
The 4-day week thus combines the benefits of work
staggering with an additional advantage.
If this measure were introduced
and working days spread over a six-day pe~i6d, daily vehicle miles trav-
eled for the journey to work could be reduced by as much as a third.
Assuming 30 percent of motor vehicle miles traveled are accounted for
by the journey to workl,and 25 percent of the labor force would be on
a 4-day work week by 1977, a maximum reduction of 2.5 percent in daily
2
vehicle miles traveled could be achieved.
All of these assumptions, how-
ever, appear highly optimistic.
Moreover, increased leisure would undoubt-
edly result in additional vehicle miles traveled for recreational and
other trips (although these are likely to be at off-peak periods and in
relatively less polluted areas).
The profound social and economic implications of a large scale
shift to the 4-day week suggest that this measure should be considered
from a broader perspective than congestion relief or air pollution con-
trol alone.
Such an examination of the 4-day work week, although beyond
the scope of the present study, should be a priority area for further
research.
1. Journey-to-work trips in a motor vehicle account for slightly less
than 30 percent of total motor vehicle trips in the Los Angeles region,
26 percent in the San Francisco area and 15 percent in the Tri-State
(greater New York) region.
2.
(.33)(.30)(.25) = 2.5 percent
-------
- 28 -
Preliminary Cost EstUnat~~~_~ic Transport Improvements
Within the time available to complete this report, preparation of
detailed estimates of the investment costs required to substantially improve
public transportation was not possible.
However, we did prepare prelimin-
ary estimates of potential investments in public transport between the
period 1970-1980 to allow identification of the overall orders of magnitude
implied.
The estimates included a mix of short-lived, or off-the-shelf
items (buses, transit cars, and so forth) and very long-lived or custom
built items (new rights-of-way, including track and structures for high
capacity rapid transit).
The modes of transport included were bus guide-
way systems, rapid transit and commuter rail.
Not included were demand-
responsive transit systems and generally untested technology.
The estimates
include substantial unmet demands (at 1971 population levels) which are
expected to be fulfilled or initiated before 1980.
The basic approach was to estimate rail transit on the basis of work
under way and plans in process, and bus transit on the basis of industry
replacement cycles, population growth, the rate of urbanization and changes
in real per capita income.
These estimates do not include the scope of
changes (1. e. ,
substantial i~prR'\{~1Ilf;!H~s ,~p ~uq:l,~c. transport services) which
, ,
apparently are needed to meet national air quali~y standards by 1975, and in
that context must be considered conservative.
Table 2 summarizes the estimates
for the six cities focused upon in this study.
The estimates indicate that about $13.8 billion will be required for
investment if the existing plans plus some moderate improvements (such as
people movers) are implemented.
-------
- 29 -
Table 2
1980 INVESTMENT ESTIMATES FOR URBAN TRANSPORT
$ Millions (1971)
CBD People
City Rapid Rail Suburban Rai 1 Buses Movers Total
New York City 2,833.1 2,223.2 587.3 250.0 5,893.6
Chicago 1,011.2 240.9 162.3 12.0 1,426.4
Washington, 2,970.01.1
D. C. 3./ 6.0 2,976.0
Los Angeles 2,162.3 :./ 24.0 2,186.3
San Francisco 427 . i1/ 'l:./ 16.0 443.7
Denver 852.6 'l:./ 4.5 857.1
----- - - - - - - - - - - - - - - - - ------ -----
Total 10,256.9 2,464.1 749.6 312.5 13 , 783. 1
1.
Apprbximately $200 million is now under contract or in active bidding.
2. Estimates for buses are not shown except for New York and Chicago
where bus investment plans were specified separately as part of comprehen-
sive multi-modal plans. However, our estimates for bus investment needs
for all metropolitan areas over 1 million population (excluding New York
City, Chicago, BostOIL, Philadelphia and Cle've'land-- all of which include
buses as an integral part of multi-modal plans) amount to less than $119
million. Washington, D.C., San Francisco and Denver represent a relatively
small percentage of this total.
3. This represents 30 percent of the full cost.
plete and 30 percent is under contract.
About 70 percent is com-
-------
- 30 -
The estimate's should be considered within the context of severe
financial difficulties facing most transit systems across the United
1
States.
Most systems cannot even cover operating costs, let alone
finance ,improvements.
Consequently, federal funding would be required.
However, if (as provided for in The Urban Mass Transportation Assistance
Act of 1970) the Federal government provided two-thirds of the $13.8
billion investment needs estimated above, over 90 percent of federal
Łund~ obligated for the entire country would be expended on 'just the
six cities of New York, Chicago, Washington, D.C., Los Angeles, San
Francisco and Denver alone.
Clearly, if even modest improvements in
public transport are to be made, a much greater federal commitment will
2
be required.
Operating Costs for Washington. D.C.
In addition to capital investment requirements, improved public
transportation will generate increased operating costs.
Again, estimates
for the six cities are not possible at this point in the study.
Moreover,
the orders of change will of course depend on the specific operating charac-
teristics of each city's transportation system.
However, estimates have
been prepared for Washington, D.C. for the year 1975.
,"" I
The estimates must
\" (
be considered as rough orders of magnitude.
The following assumptions were
1. See Chapter 5, "Improvements in Public Transportation," section on
"Ins ti tu tional Feas ibility. "
2. It should be repeated that public transport improvements alone are
a necessary but not sufficient condition for reducing motor vehicle
traffic. However, if vehicle miles traveled are to be reduced by other
measures, substantially improved public ~ransport would be required to
provide alternative means of making trips.
-------
- 31 -
made:
(1) ~he Metro (the new rapid rail transit under construction) will
not be in operation by 1975 and all bus services will be used; (2) there
would be about a 10 percent passenger diversion to bus transit by suburban-.
ites and a somewhat smaller diversion for trip makers within the District
of Columbia; (3) no cost increases would be required for off-peak service --
only for the increased demands during the peaks; (4) no change in labor
practices; (5) two fare assumptions have been made -- no fare change to
1975 and a 12-15 percent increase; and, (6) only moderately improved ser-
vices.
Table 3 summarizes the results of these estimates.
Table 3
BUS TRANSIT ESTIMATED REVENUES AND EXPENSES FOR
THE ~SHINGTON, D.C. REGION, 1969 AND 1975
Year
Revenue
($ millions)
Cost
($ millions)
Deficit
($ millions)
Passengers
(millions)
Deficit per
Passenger
(cents)
1969 50 58 8 150 5
1975-No Fare
Change 65 80 15 186 8
1975-12-15%
Fare
Increase 75 80 5 186 3
-------
- 32 -
Examination of Table 3 shows that the overall system deficit
would be in the order of $15 million in 1975, if no f~re increases were
provided, and about $5 million with a fare increase of about 15 percent
(about a lot increase for most passengers).
Thus, the deficit would in-
crease sharply from the 1969 level without any fare changes, and probably
decline slightly with a moderate fare increase.
However, even a deficit
of $15 million annually by 1975 would not represent an insurmountable
cost obstacle (in contrast, perhaps, to the capital investment require-
ments) for expansion of the service needed, especially if parking taxes
are imposed to restrain motor vehicle use.
Revenues from such a tax
would undoubtedly go a long way toward covering such deficits.
Operating Deficit for the United States
In 1970 for the United States as a whole, the total operating
deficit for transit operators amounted to about $288 mi1ion (a large
part of which was accounted for in large cities such as New York, Boston,
San Francisco and Philadelphia where air pollution problems are at their
worst).
If no improvements are made in existing public transport ser-
vices, the deficit (conservatively estimated) can be expected to
double by 1975 (and is probably more likely to be closer to $600 mi1-
1i on) .
If maj or improvements W'ere :!instituted, operating deficits
would be even greater, particularly if fares were not increased.
1. For further discussion of operating deficits and several proposals
currently under consideration for federal assistance, see Chapter 5,
"Improvements in Public Transportation," section on "Institutional
Feasibility. "
-------
CHAPTER
1
INSPECTION, M.o\INTENANCE AND RETROFIT
Definition of Terms
Broadly defined, the programs discussed in this chapter all involve
(1) the inspection of in-use vehicles, (2) the identification of high emit-
ters (and, hopefully, the provision of diagnostic information), and (3) some
requirement for subsequent corrective action (whether at inspection stations
or garages).
Conceivably, some corrective actions could be required with-
out inspection.
For example, spark plugs or breaker points could be replaced
on the basis of their expected life.
Corrective action might also be requir-
I
ed on the basis of records kept for the federal new car warranty program.
Nevertheless, inspection appears to be a necessary prerequisite to corrective
action for in-use vehicles on two counts:
(1) to determine what corrective
action needs to be taken, and (2) to reduce possible underservicing or over-
servicing.
For these reasons, we assum9 that inspection should be an inte-
. 1. , t f't 2
gral part of any effective program ~nvo v~ng ma~n enance or retro ~ .
1. The current maintenance procedure for one major motor vehicle
manufacturer (General Motors) requires periodic servicing of vehicles
by motorists. A maintenance schedule is specified at the time of
purchase, and must be complied with and documented to assure con-
tinuing coverage under the warranty. Conceivably, this documenta-
tion could be the basis for requiring corrective action by motorists
and/or manufacturers.
2. In this regard, one publicopinioR survey showed considerable
apprehension about the potential abuses of emission inspection pro-
grams conducted by private garages. Northrop Corporation, Mandatory
Emission Vehicle Inspection and Maintenance, Final Report, Volume I:
Summary' (Anaheim, California: Northrop Corporation in association
with Olson Laboratories, Inc., 1971), p. 3-1.
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1-2
Maintenance Procedures
A number of maintenance procedures have been proposed for the con-
trol of carbon monoxide and hydrocarbons as summarized in Table 1-1.
Retrofit System~
1
Exhaust control systems for retrofit on most pre-1968 cars have
been developed by various auto manufacturers and generally follow a somewhat
similar approach (combining modifications and adjustments to the carburetor,
the distributor and vacuum advance and installation of a retrofit device.)
Existing retrofit systems cab be installed relatively rapidly at local service
. 2
stat~ons.
1. Depending upon factors such as age and degree of mgintenance, these
vehicles may emit many times more pollution than new models. Pre-1968
vehicles are being phased out of use at a national rate of approximately
10 percent per year, but will continue to contribute disproportionately
to motor vehicle air pollution for the next few years unless control de-
vices are developed and applied. This disproportionate contribution could
be even greater if substantial price increases are required for newer ve-
hicles having emission control and safety equipment, with the result that
the phase-out of older vehicles is slowed.
2. "Industry-type" retrofit devices involve manipulation of the spark
advances and adjustment of the air-fuel ratio. Other, more sophisticated
devices (e.g., catalytic converters,therma1 reactors and exhaust gas re-
circulation) are currently under investigation by EPA. Such devices may
be particularly effective for reducing nitrogen oxide emissions and,
consequently, may have applicability through the 1972 model year (after
which nitrogen oxide controls are required nationally). A comprehensive
Rurvey of most reasonably practicable retrofit devices is currently being
conducted by Olson Laboratories for EPA. See, Olson Laboratories in as-
sociation with Northrop Corporation, "Analysis of Effectiveness and Costs.
of Retrofit Emissions Control Systems for Used Motor Vehicles," prepared
for the U.S. Environmental Protection Agency, December 1971. (Mimeographed
draft.)
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1-3
Table 1-1
INSPECTION AND/OR MAINTENANCE PROCEDURES
Procedure
Description
Visual Inspection
Minor Tune-up Requirement
Major Tune-up Requirement
Exhaust Measurement at Idle
Exhaust Measurement under
Load
Exhaust Measurements
Load for Purposes of
Diagnosis
under
Check to see if control devices or systems
N ""bl" 1
are operative. ote any v~s~ e em~ss~ons.
Check adjustments of idle speed, air-fuel
ratio, and spark advance, resetting these
to manufacturers specifications.
Replace spark plugs and breaker points on
basis of expected life. Possibly replace
other parts of engine. Would also include
adjustments of minor tune-up program above.
Identify high emitting engines through ex-
haust measurement while the engine is in
idle operating mode.
Identify high emitting engines through ex-
haust gas measurement while engine is iner-
tially loaded by use of a dynamometer.2
Same as above, but includes techniques to
indicate the kinds of adjustments or re-
pairs necessary.
Source: Adapted from U.S. Department of Health, Education and Welfare,
National Air Pollution Control Administration, Control Techniques for
Carbon Monoxide, Nitrogen Oxide, and Hydrocarbon Emissions from Mobile
Sources (Washington, D. C.: Government Printing Office, March 1970),
Chapter 4.
1. Although this category is included for comprehensiveness, its practi-
cability and effectiveness are open to serious question. For one thing,
exhaust control systems are increasingly being built with modifications
which are difficult to inspect visbally (e.g., carburetor adjustments).
Second, and contrary to conventional wisdom, visual inspection usually
involves more muscular fatigue (e.g., opening and closing hoods for hun-
dreds of vehicles) than other inspection procedures. And finally, visual
inspections tend to be highly subjective.
2. Realistic emission tests may require exercising the engine under stress
(i.e., "loading") in order to simulate actual driving conditions.
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1-4
Air Pollution Control Potential
Federal air pollution control legislation contains tWo provisions
pertaining to inspection, m~intenance and retrofit.
Section 110 (a)(2)(G)
of the Clean Air Act as amended, indicates that state air p~llution imple-
mentation plans tm.lst provide "to the extent necessary and2racticabl~, for
periodic inspection and testing of motor vehicles to enforce compliance
with applicable standards. . ."
(Emphasis added.)l
Section 210 of the
same legislation provides that "the Administrator is authorized to make
grants to appropriate State Agencies in an amount to tWo-thirds of the
cost of developing and maintaining effective vehicle emission devices and
systems inspection and emission testing and control programs. . ."
(Emphasis
added.)
In this enabling legislation, the key words respecting inspection,
m~dntenance and retrofit appear to be "necessary." "pr~cticable" and
"effective," each of which is taken up below.
Necessar„
For an inspection program (and maintenance and retrofit) to be deemed
necessary implies a determination (presumably on the part of state and
local air pollution officials and EPA regional representatives) that the
seriousness of motor vehicle air pollution warrants corrective action.
Such a determination as to necessity should be a function of ambient air
1. A review of the Clean Air Act's legislative history does not reveal
exactly what was meant by "applicable emission standards." This phrase
could refer to federal new car emission standards for post-1967 vehicles,
to in-use vehicle emission standards established by a state or locality,
or both.
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1-5
quality (and particularly motor vehicle emissions) in any given area.
In many states, emission inspection programs may be only necessary for
major metropolitan areas, if at all.
Practicable
-----
Implicit in the notion of practicability are considerations as to
test regime, organizational arrangements, diagnostic information, costs,
manpower requirements and implementation times.
I~~t-L~im~ .
For inspection, maintenance and retrofit to be consid-
ered practicable implies an emissions test which is quick, cheap and accurate.
Such a test requires both a method for exercising the motor vehiclel and
available instrumentation for measuring the resulting emissions.
Exe rc is ing
the motor vehicle can be accomplished under various test routines or driving
cycles, which run a motor vehicle through a specified sequence of operating
modes (e.g., idle, acceleration, deceleration, cruise).
Cycles can vary
according to the number of modes examined, the specific sequence of modes,
the time spent in each mode, the rate of acceleration and deceleration, and
the maximum speeds achieved.
Differing test cycles result in differing emissions, differences which
are often substantial.
Ideally, test cycles should be comprehensive so as
to reflect closely the typical driving patterns observed within a specific
area.
Test cycles should also correlate acceptably with the full federal
certification procedure.
HONever, practical requirements (i.e., for a
1.
Except, of course, in the case of the idle test.
-------
1-6
quick and cheap test) preclude
a lengthy simulation of actual driving
1
test.
conditions or the full federal
Choosing a test cycle for emission inspection programs is the key
decision to be msde in designing a program.
Various tests and test cycles
measure differing amounts of emissions, provide differing degrees of
diagnostic information, and hence have differing emission reduction
potentials.
They also imply differing costs, facility and manpower
requirements, implementation times and organizational arrangements for
administering the program.
The major tests and test cycles currently
under study for EPA and other air pollution control agencies are indi-
cated in Table 1-2.
Decisions as to which tests or test cycles are practicable in the
sense intended by the Clean Air Act are yet to be made.
The issues are
complex, highly technical, and cannot be resolved until completion of
several investigations currently being conducted under EPA sponsorship.
1. Motor vehicle emission tests can be conducted for any of three
objectives: (1) to certify a new car as meeting the existing emis-
sion standards (the so-called full federal certification procedure);
(2) to ensure quality control at the end of the assembly line; and
(3) to determine if in-use vehicles are releasing "excessive" emis-
sions. In the present discussion, concern is primarily with tests
for this last purpose, which does not require precise measurement
of absolute emissions as per the full federal certification procedure.
Consequently, we do not consider the full federal certification pro-
cedure (which presently requires a l2-hour "soak", followed by a 23-
minute test) except to note that an acceptable correlation should
exist -- at least on a pass/fail basis -- between the full federal
certification procedure and the inspection of in-use motor vehicles
for maintenance and retrofit purposes.
-------
1-7
Table 1-2
TEST REGIMES
Test Category
Description
1.
Idle
Unloaded test in which exhaust emission
measurement is taken only while engine is
in idle mode.
2.
Steady State
Loaded testl in which exhaust emission
measurement is taken at idle and at one
or various cruise speeds. No measurement
of transient modes (i.e., during change
from one mode to another). Typical example:
key-mode test.
3.
Transient Mode
Loaded test2 in which exhaust emission
measurement is taken during idle, accelera-
tions, various cruise speeds, and decelera-
tions. Typical examples: ACID test, 7 mode-
7 cycle test.
4.
Diagnostic
Loaded test using sophisticated instrumenta-
tion to measure both exhaust emissions and
performance of specific engine components.
Test operates on a pass/fail basis by speci-
fying performance parameters for various
specific engine components (e.g., an oscilli-
scope can be used to determine if ignition
system is performing according to manufactur-
er specifications). Of primary use in
identifying those repairs or adjustments
needed to reduce emissions.
Source: Adapted from U.S. Department of Health, Education and Welfare,
National Air Pollution Control Administration, Control Techniques for
Carbon Monoxide, Nitrogen Oxide, and Hydrocarbon Emissions from Mobile
Sources (Washington, D. C.: Government Printing Office, March 1970).
Chapter 4.
1. The loaded test of the Steady State category is based on a road
factor which simulates the internal friction within the vehicle due
moving parts and the air friction which occurs as the vehicle is in
loading
to
motion.
2. The loaded test of the Transient ~lode category is based on the road
loading factor used in the Steady State category, and ap inertial load
factor which simulates the weight of the vehicle. This latter factor is
only important during accelerations and decelerations.
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1-8
Data on which to base these decisions are e~pected to be forthcoming in
early 1972.
Important issues to be resolved at that time respecting each
test or test cycle, include:
(1) its ability to identify high emitters;
(2) its accuracy, both with respect to local driving conditions and the
full federal certification procedure; and (3) its ability to yield diag-
nos tic information as to the source(s) of excessive emissions and the
adjustments or repairs which would be required.
Organizational arrangements.
Closely connected with the above
considerations as to test regime are questions of organization and
administration.
O~viously, the practicability of any emission inspection
program will depend importantly upon the organizational arrangements for
administering inspections.
The three major organizational alternatives
for emission inspection programs are summ3rized in Table 1-3.
Of the three major organizational arrangements identified in Table 1-3
for administrating inspection programs, the state-owned and operated alter-
nativel appears the most practical for two reasons.
First, state-owned and
operated facilities have much higher motor vehicle inspection capacities
1. Although Table 1-3 summarizes the organizational alternatives at a
state level, emission inspection programs could conceivably be owned and
operated by local governments (e.g., counties, municipalities). Since
the scope of motor vehicle air pollution in many areas may c0incide more
closely with local boundaries than with state borders, local government
participation may be appropriate, although, as we note below, this would
pose institutional problems for multi-county, bi-state or tri-state metro-
politan areas.
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1-9
Table 1-3
ORGANIZATIONAL ARRANGEMENTS FOR ADMINISTERING INSPECTION PROGRAMS
Organizational Arrangements
Administrative Implications
1.
State Owned and Operated
State acquires necessary sites,
constructs inspection facilities,
equips lanes, staffs facilities
and manages total program.
2.
Privately Owned and
Operated
State selects private contractor to
manage overall program, including
site selection and construction of
inspection facilities. Actual
ownership and operation in private
sector subject to applicable state
regulations.
3.
State Licensing of
Existing Privately Owned
Facilities
State qualifies and certifies exist-
ing vehicle maintenance centers to
perform vehicle emission inspection.
State provides total program adminis-
tration and management.
Source: Adapted from Northrop, Corporation, Mandator~ Emission Vehicle
Inspection and Maintenance, Final Report, Volume I: ummary (Anaheim,
California: Northrop Corporation in association wi~ Olson Laboratories,
Inc., 1971). Another arrangement for inspection of in-use vehicles would
be through spot checks whereby state officials with mobile equipment would
move about a given area and temporarily locate along major thoroughfares,
selecting vehicles for tests at random. However, all available research
indicates that the effectiveness of maintenance depends upon the proportion
of the total vehicle fleet inspected. Consequently, inspection programs
which check only a small proportion of the total vehicle fleet have result-
ed in correspondingly small emission reductions. It is conceivable that an
approach combining spot inspections with strong incentives (e.g., heavy
fines) could motivate the majority of motorists to maintain their vehicles
in conformance with emission standards, although there has been no experience
to date with this approach.
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1-10
(on the order of 50,000 vehicles per station per year) than do individual
service stations, either under state management or under state regulation.
Individual service stations probably have average throughputs of approxi-
1
mately 800 vehicles per station per year. These figures, in turn, imply
higher overall efficiency (and hence lower per vehicle costs) for state-
owned and operated emission inspection programs.
Second, state-owned and
operated inspection programs entail a separation of the fuoctions of
inspection and repair.
This division of labor by function can be impor-
tant in reducing over-servicing and is a highly desirable aspect of emission
2
inspection programs, according to available public opinion surveys.
If state-owned and operated facilities are the most appropriate for
emission inspections, only three jurisdictions would be able to build upon
existing safety inspection programso
Currently, 32 states (including the
District of Columbia) do have periodic motor vehicle safety inspection
programs.
Of these, however, 29 operate under a state-appointed system,
with only three (Delaware, New Jersey and the District of Columbia) having
state-owned and operated insp.=tion facilities.
1. These figures are for safety inspection programs in New Jersey (state
owned and operated) and North Carolina (private sector). The figure
for state facilities is probably an average which more closely approxi-
mates single lane stations than multi-lane facilities. New Jersey has
some multi-lane facilities, but most are single lane stations.
2. Northrop Corporation, Mandatory Emission Vehicle Inspection and
Maintenance, Final Report, Volume I: Summary (Anaheim, California:
Northrop Corporation in association with Olson Laboratories, Inc.,
1971), p. 3-1.
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1-11
Dia~nostic information.
Vehicles may generate "excessive" emissions
because of deterioration, maladjustment or malfunction. 1
Assuming high-
emitters can be identified, the degree to which a test or test-cycle can
isolate the cause of excessive emissions will determine its potential ef-
ficacy for subsequent corrective action.
Furthermore, accurate diagnostic
information can reduce both over-servicing and under-servicing.
Diagnostic
information appears especially important at the inception of inspection
programs, when most mechanics have little or no experience with maintenance
d. . i 2
and retrofit for re uC1ng em1SS ons.
Costs.
A central consideration as to the practicability of the
tests and test cycles concerns costs.
There are many cost components of
any inspection program, including program start-up costs, construction
1. "Excessive" is enclosed in quotation marks
e~ission standards for in-use vehicles in most
established, either in enabling legislation or
so as to emphasize that
jurisdictions remain to be
by administrative order.
2. In addition to the above, diagnostic information could contribute to
the federal warranty program. Section 207(b) of the Clean Air Act
Amendments of 1970 states that "at such time as he [the EPA Administrator]
determines that inspection facilities or equipment are available" to per-
form emission inspections, he must require manufacturers to warranty
emission control systems for five years, or 50,000 miles, whichever comes
first. This strong performance warranty will replace the relatively weak
defect warranty which is currently in force and should contribute impor-
tantly to enforcing upon manufacturers the responsibility for providing
reliable emission control systems.
A central determination in judging liability will be whether the
motor vehicle was operated in accordance with manufacturer specifications.
If an emission inspection program yields sufficient diagnostic information
to allow this determination, the warranty provision may be substantially
strengthened. Whether, in fact, federally funded inspection programs should
be used for this purpose is a major policy issue.
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1-12
costs, operating and maintenance costs, costs to motorists for repairs
(including inconvenience),l and so forth.
A discussion of these costs
is unnecessary for present purposes, although cost estimates for inspec-
2
tion, maintenance and retrofit are available from various reports. Never-
theless, it appears that the following qualitative conclusions can be
drawn:
1. Large vehicle throughputs at state-owned and
operated facilities, along with avoidance of taxes
and the need for private sector profits, seem to
permit significantly lower per vehicle testing costs
than for either of the other two organizational al-
ternatives. Per vehicle capital equipment costs would
1. Costs to motorists should be calculated on a net basis since some
corrective actions (e.g., maintenance) may entail ancillary benefits to
motorists (e.g., decreased fuel consumption). On the other hand, other
corrective actions (e.g., retrofit) may have the opposite effect. Early
reports from one manufacturer indicated that of 59 cars equipped with
retrofit systems, 12 were made less drivable by the installation of the
retrofit system, and 35 cars remained unchanged. (General Motors Corpor~
ation, The General Motors Used Car Emission Control System, December 1969).
The adverse effects of retrofit systems may include rough operation at
low speeds, rough idling speed, and an increase in creep speed. It is per-
haps for this reason that motorists appear reluctant to purchase a retrofit
system, at least according to initial evidence. For example, an intensely
promoted two-month marketing test recently conducted in Phoenix by General
Motors revealed that only 528 of a possible 334,000 pre-1968 motor vehicles
were equipped with retrofit (at a cost of $20 per vehicle). Ideas, News-
letter of International Research and Technology, August 1970, p. 67.
2. See, for example, Northrop Corporation, Mandatory Emission Vehicle
Inspection and Maintenance, Final Report, Volume I: Summary (Anaheim,
California: Northrop Corporation in association with Olson Laboratories,
Inc., 1971), Chapter 8.
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1-13
be substantially lower in
systems, again because of
tion program capacities.1
state-owned and operated
substantially larger inspec-
2. Should testing under load be required (with the
resulting requirement for dynamometers), state-owned and
operated inspection programs appear to be the only
feasible alternative. Large capital outlays required
for acquisition of expensive equipment, plus the appar-
ent need for the training and staffing of professional
personnel, appear to preclude private sector operation
of inspection programs with loaded testing (i.e., those
involving dynamometers). It seems reasonable to assume
that most service stations would be unwilling to invest
more than perhaps $2,000 for capital equipment in order
to be involved in an emission inspection program.
Manpower Requirements.
The skill required of personnel to
conduct emission tests varies considerably with the sophistication of
the inspection procedure.
The idle test procedure, which con-
sists of inserting a sampling probe in the vehicle's exhaust pipe and
noting the metered reading, requires little training.
More sophisticated
inspection procedures, especially loaded ones, require personnel with
additional training.
Indicative of the relative training require-
ments, one study concluded the idle test would require approximately
87 classroom hours of training; the key mode, 142; and the diagnostic
test, 174.2
The availability of trained manpower need not be a binding
1. This ignores, of course, the cost of drivers' time (which is probably
greater in large public stations).
2. See, Northrop Corporation, Mandatory Emission Vehicle Inspection and
Maintenance, Final Report, Volume'VI (Anaheim, California: Northrop
Corporation in association with Olson Laboratories, Inc., 1971), p. 2.
These numbers, in an absolute sense, are somewhat speculative, and, indeed,
appear high for the idle and key-mode tests. More reliable estimates will
be forthcoming at the conclusion of studies to determine the present capa-
bilities of auto mechanics in this area.
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1-14
constraint on the implementation of an inspection program, however, since
the time required for facility construction or modification will be
1
ficient to train the required manpower, regardless of cycle.
suf-
Implementation time.
The time required to physically implement a
state-wide emission inspection program (whether of the state-owned and
operated, the state-regulated, or the private sector variety) is probably
small (on the order of six months to one year).
This "physical implementa-
tion time" would include the time required for construction facilities,
acquiring staff and training professional personnel, and would of course
depend to some degree upon the testing procedure selected.
However, the
"real implementation time," to include total elapsed time from considera-
tion of program initiation by the policy-makers until actual program oper-
ation will probably be considerably longer, among other things because of
the political problems involved (i.e., resistance to programs on the part
of strong rural interests in some state legislature~ opposition from
automobile owners associations, and so forth).
Effective
Assuming inspection, maintenance and retrofit are necessary and
practical, the Clean Air Act requires that federally funded programs be
demonstrated to be effective.
Demonstrating pollution control effectiveness
entails measuring the emission reductions achieved by maintenance and retrofit.
1. In early 1971 it was announced that the Federal Government, under the
Manpower Development and Training Act,would establish a $1,000,000 training
program for mechanics, focusing on effective control of exhaust fumes and
unburned hydrocarbons. The program is administered out of the Department
of Health, Education and Welfare in cooperation with EPA's Office of Air
Programs and major automobile manufacturers.
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1-15
For any area's vehicle population, the potential emission reductions
~onsist of both the initial reduction (achieved at the time of maintenance
and retrofit) and the reduction over time (and, more specifically, the
deterioration rate of maintenance and retrofit).l The potential for initial
emission reductions will depend upon the accuracy of the test procedure,2
and the level at which emission standards are set (which in turn determines
the test rejection rate») Preliminary indications concerning rejection rates
seem to indicate that for most states these rates should not exceed 20 to 40
percent so as to prevent a critical overload of commercial repair facilities
and to eliminate heavy burdens on the inspection program which occur because
of demands for retest.4
The probability of adverse public reaction to high
rejection rates should also be a central considerati~n when inspection pro-
grams are developed.
1. Actual on-the-road reductions are significantly less than initial
reductions due to the deterioration of emission control equipment ef-
ficiency with accumulated mileage (referred to here as the reduction
!'over time").
2. Accuracy, of course, depends on which test or test cycle is chosen,
ranging from visual inspection for the presence of control devices to
exhaust measurement under load on a dynamometer to diagnose the cause
of high emission and to indicate what corrective action should be taken.
3. Other factors affecting the potential for initial emission reductions
include the maintenance skills of mechanics, the age distribution of
vehicles, and the degree of voluntary maintenance.
4. Ernst and Ernst, A Study of Selected Hydrocarbon Emission Controls,
Report to the U.S. Department of Health, Education and Welfare, July,
1969, and Marion F. Chew, Auto Smog Inspection at Idle Only, Report for
the Society of Automotive Engineers, No. 690505, 1969.
-------
1-16
Unfortunately, present knowledge does not permit a determination of
the deterioration rates of maintenance and retrofit.
Deterioration over time
will depend upon a number of unknowns, such as the reliability of post-197l
emission control systems (not to mention the uncertainty attached to post-
1975 emission control systems, with potentially more sophisticated technology).
Differing deterioration rates for inspection and maintenance are shown in
Figure 1-1.
As indicated, an initial emission reduction (from e3 to el) is
achieved at the time of inspection and maintenance (tl)'
Reductions over time
depend upon the slope of the deterioration curve.
Assuming an early substantial
deterioration (curve d), fully half of the initial reduction would be dissi-
pated within two months; assuming linear deterioration (curve dl) the same
initial reduction would return to half its pre-maintained level within six
months; assuming late substantial deterioration (curve d2) half of the initial
reduction would disappear after nine months.l
Differing deterioration rates, in turn, require differing intervals
between in~pections.
If, for example, initial reductions are dissipated
rapidly, frequent inspection would be necessary to maintain vehicles below a
given level (say, an emission standard for in-use vehicles).
Assuming a target
emission level at e2, as illustrated in Figure 1-1, the appropriate interval
between inspections would be determined by that point in time (i.e., t2) at
which emissions returned to the target level.
Whether the time to t2 is two
months (tl-t2'), six months (tl-t2"), or nine months (tl-t2'") has an obvious
bearing on the costs and feasibility of any e~1aust emissions inspection program.
1. These deterioration curves and time periods, it should be stressed, are
solely for purposes of illustration. Further empirical research is required
to determine actual deterioration rates over time.
-------
Figure 1.-1
HYPOTHETICAL DETERIORATION RATES FOR INSPECTION AND MAINTENANCE
Emissions
With No - - -----~...~ - -
e)
Maintenance .... ~ I
w 1 "'---"-
,....:j ,- ,,",
U
H I " II!!. I early deterioration ,.....
::c
w dl~ ,," I l I
,.....
~ Target .1. ~
~ Emissions e2 . . . . . ...... . , . . . .
w , linear deterioration
p, Level I
U) I
z I
a I
H late deterioration
U) d2
U) Emissions I
H
::8 Immediately el
w
Following
Maintenance
,
tl t2
inspection
and
maintenance
II
t2
"'
t2
ELAPSED TUrn (MONTHS)
-------
1-18
In sum, the slope of deterioration curves for maintenance and
retrofit (that is, the dynamics of deterioration over time) is so highly
uncertain that~ absent valid empirical data,l it is impossible to draw
Arriving at these conclusions will
definitive conclusions at this time.
require an analysis of findings from pilot p~ograms (probably of 12- to
18-month duration), some of which will probably be initiated by EPA in
1972.
As data are ,accumulated, the effectiveness over time of inspection,
maintenance and retrofit (and the costs of alternative procedures) can
begin to be established.2
1. A number of empirical studies are available but are of questionable
validity for any of the following reasons: (1) reliance upon testing
methods which do not correlate with the full federal certification
procedure (i.e., measurement of mass emissions); (2) continual changes
in motor vehicle characteristics; and (3) difficulties in conducting
controlled experiments. In the latter connection, for example, the
so-called California study (Arthur J. Hocker, "Exhaust Emissions from
Privately Owned 1966-1970 California Automobiles: A Statistical Eval-
uation of Surveillance Data," (Los Angeles: California Air Resources
Laboratory, July 15, 1971» provides deterioration data which enable
estimations of present and projected pollution levels. Although suf-
ficient for the state's purposes, the study does not distinguish
between deterioration rates for (1) vehicles maintained on a manda-
tory basis (e.g., as would be required under an inspection-maintenance
program) and (2) vehicles maintained on a complaint basis (e.g.,
maintenance only when non-function occurs). Nor does the study
distinguish by place of maintenance. Such distinctions, of course,
are required if the effectiveness over time of mandatory maintenance
for a given area's vehicle population is to be determined.
2. At such time, these data should in turn be compared with ambient
air quality data so as to arrive at a more conclusive determination as
to the necessity of inspection, maintenance and retrofit, both on a
state-wide basis and for major metropolitan areas. In the final anal-
ysis, the desirability of inspection, maintenance and retrofit will
be a function of ambient air quality for any given area as weighed
against the practicality and effectiveness of corrective action, as
determined by studies now under way or shortly to be initiated.
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1-19
Absent this information, it is nevertheless possible to arrive
at a rather broad range of initial emission reductions (i.e., prior to
deterioration over time) which can be reasonably expected from inspection,
maintenance and retrofit. 1
Maximum Feasible Emission R~duction
Inspection and Maintenance
On the basis of research performed by TRW, Inc.,2 Northrop
Corporation,3 and the State of New Jersey,4 as well as information
from EPA officials in the Bureau of Mobile Source Pollution Control,
it appears that the most likely initial reduction in aggregate carbon
monoxide emissions5 would be on the order of 10 to 25 percent.
However,
1. Since the initial emission reduction potential of inspection, maintenance
and retrofit depends upon a number of variables (e.g., accuracy of test pro-
cedure, test rejection rate, skill of mechanics in maintenance and instal-
lation of retrofit systems, age distribution of vehicles for any given area),
it is not possible to state a single generalized value for this control.
2. TRW Systems Group, "Emission Factors for Motor Vehicles" (internal
documentation: McLean, Va.: TRW Systems Group, TRW, Inc. October 21,
(Mimeographed.)
1971).
3. Northrop Corporation, Mandatory Vehicle Emission Inspection and Main-
tenance, Final Report, Vol. I: Summary (Anaheim, Calif.: Northrop Corp.
in Association with Olson Laboratories, Inc., 1971).
4. New Jersey Department of Environmental Protection, Bureau of Air
Pollution Control, Motor Vehicle Tune-up at Idle -- The New Jersey REPAIR
Pro;ect (Trenton, New Jersey: New Jersey Department of Environmental
Protection).
5. By "aggregate" we mean the carbon monoxide attributable to light duty
motor vehicles in any given area. See Appendix A. To the extent that other
motor vehicles (e.g., trucks or buses) or stationary sources (e.g., space
heating) contribute importantly to an area's emissions, the reductions
possible from inspection and maintenan~e would be less than estimated here.
-------
1-20
it appears that values in the upper range (particularly 20 to 25 percent)
are decidedly less likely than those in the lower range (particularly
10 percent).
It should be stressed that these values represent a definite
upper bound for the air pollution control potential of inspection and
maintenance, since subsequent deterioration of maintained vehicles (in
the interval between inspections) would lessen the effectiveness of this
control.
For example, assuming an initial reduction of 10 percent and
deterioration to original (i.e., pre-maintained) conditions after six
months, the aggregate emission reduction, when averaged over a year's
period, would amount to only 5 percent.
Similarly, if "complete" deteri-
oration occurred after nine months, an annual aggregate emission reduction
of only 7.5 percent would be achieved.
Actual emission reductions, achiev-
able from inspection and maintenance may also be overstated due to dif-
ficu1ties in .( 1) abtaining complete compliance from all in-use vehicle
owners, and (2) securing governmental cooperation in multi-jurisdictional
metropolitan areas (see below).
Retrofit
Based upon preliminary results from on-going EPA research it
appears that currently available "industry-type" retrofit devices will
reduce carbon monoxide emissions by 20 to 25 percent for pre-controlled
-------
1-21
vehicles.l
Aggregate emission reductions, therefore, depend upon any
area's proportion of pre-controlled vehicles and their associated vehicle
miles traveled (bearing in mind that older cars are driven less than
newer cars).
Assuming at least three years would be required for enabling
legislation and the certification and installation of equipment, it
appears the earliest date for completion of a retrofit program would
be 1975.2
With this assumption, and using vehLcle age distribution
and vehicle miles of travel by age data, the upper bound of possible
carbon monoxide reductions can be readily calculated for any area.
A methodology for estimating potential emission reductions,
as well as the assumptions we have used,
is indicated in Appendix A.
In California where pre-controlled cars (pre-1966) will account for
only approximately 8 percent of the total miles driven in 1975, a
25 percent emission reduction for pre-controlled vehicles would a-
chieve an aggregate reduction of 2.9 percent.
Continuing the Cali-
fornia example, pre-controlled cars will account for approximately
3 percent of the total miles driven in 1977, where 25 percent emis-
sion reduction for pre-controlled vehicles would result in an ag-
gregate reduction of only 1.3 percent.
1. Recently acquired data about these devices are still being analyzed by
EPA, but seem unlikely to show carbon monoxide emissions of more than
25 percent. Accordingly, and since already analyzed data indicate aver-
age reductions on the order of 20 to 22 percent, We will use 25 percent
as an upper bound in the following analysis.
2. Even this completion date may be optimistic in view of delays due to
manufacturing start-up and installation in available facilties.
-------
1-22
For the nation as a whole, pre-controlled vehicles (pre-196B)
will account for approximately 17 percent of the vehicle miles traveled
in 1975
(see Appendix A for 'details),at which time a 25 percent re-
ductions for these vehicles would yield an aggregate reduction in
carbon monoxide of 5.7 percent.
Pre-controlled vehicles will account
for approximately 8 percent of total :vehicle miles traveled in 1977; a
25 percent reduction for these vehicleS"in that year would reduce ag-
gregate emissions by only 3.2 percent.
Allowing for slight variations
in the age distribution of vehicles and vehicle miles traveled, a similar
aggregate carbon monoxide emission reduction
with retrofit would probably
result for most American metropolitan areas.l
For at least three reasons however, the above numbers probably
overstate the emission reduction from retrofit which would actually be
achieved.
First, the above analysis considered only initial reductions
following retrofit, with no provision made for deterioration over time.
Data are not currently available to estimate this deterioration exactly
but it is clear that ~ lessened effectiveness of retrofit devices
will occur, either from component failure or improper maintenance. Second,
it wOuld be extremely difficult to obtain 100 percent compliance from all
1 . 2
in-use vehicles, as assumed in the above ana ys~g. Third, complete
1. For Washington, D. C., pre-controlled vehicles (pre-196B) will account
for approximately 11.2 percent of vehicle miles traveled in 1975; a carbon
monoxide reduction factor of 25 percent would reduce aggregate emissions
by about 5.4 percent. In 1977 the figures are 5.7 percent of vehicle miles
traveled and an aggregate emission reduction of only 2.9 percent.
2. In addition to the costs involved for owners, retrofit systems reduce
the driveability of the vehicle, and hence may encourage drivers to discon-
nect the devices whenever possible.
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1-23
cooperation among neighboring governments -- an unlikely possibility --
would be required for retrofit programs in multi-jurisdiction metropolitan
areas.
In the Washington, D. C.
metropolitan area, for instance, ap-
proximately half of the motor vehicle trips probably originate outside
the District's boundaries (i.e., from Maryland or Virginia).
Accordingly,
an area-wide retrofit program would require cooperation from these neigh-
boring states, or at a minimum the counties adjoining the District of
Columbia.
Finally, it does not appear that retrofit holds out promise for
emission reaucLions over and above those which could be achieved from
maintenance alone, maintenance which would be required if retrofit were
to be introduced.
Installation of retrofit requires the adjustment of
several engine parametersl much in the way that carbon monoxide "tuning"
adjustments are made for emissions maintenance.
Given the extremely modest reduction potential of retrofit,
we conclude that this control does not warrant further examination.
The possibility of new, more effective technology may, of course,
alter the situation.
As mentioned earlier, other more sophisticated
technology (e.g., catalytic converters, thermal reactors and exhaust
gas recirculation) is currently being tested and may hold out more
promise, particularly if it is applicable to controlled vehicles as well.
1. The procedure for one manufacturer (General Motors) is to set the
engine idle to the prescribed RPM level, tune the air-fuel mixture to a
leamer (14:1 air-fuel~ ratio, disconnect the vacuum advance and install
a device which monitors coolant temper~ture and restores vacuum advance
should engine temperatures reach a certain level.
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1-24
Institutional Feasibility
The implementation of inspection, maintenance and retrofit
will require resolution at all levels of government of a number of
issues, many of which, as earlier indicated, require careful con-
sideration of complex technical considerations.
Here we attempt
only to sketch out some of the most salient additional issues, many
of which will require basic policy decisions on the part of the
Fe.dera1 Government in general and EPA
in particular.
Emission and Safety Inspection Programs
The practicality and effectiveness of emission inspection
programs may hinge upon whether such programs can be implemented as
"add-ons" to existing safety inspection programs, or whether emis-
sion inspection programs must be implemented (and hence justified on
cost-effectiveness grounds) entirely on their own.1
In the former
case, high level consultation among EPA and DOT officials presumably
would be desirable so as to formulate a coordinated federal policy
respecting inspection programs both for safety and emission checking.
1. As noted earlier, only three jurisdictions (Delaware, New Jersey
and the District of Columbia) have existing state-owned and operated
safety inspection programs. Of these, New Jersey is the only state that
requires inspection for exhaust emissions. California has a motor vehicle
inspection program for exhaust emissions at present, but it is a roadside
spot check system for 1966 or newer vehicles only.
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1-25
Federal Funding
Assuming a demonstration of necessity, practicability and effective-
ness of inspection, maintenance and retrofit, EPA presumably would wish
to make available federal funding for states (and possibly through these
states, to loca~ities).
Since the cost of emission inspection programs
1d l"
wou appear to be substantial such a determtnation by EPA would un-
doubted1y entail a request to Congress for substantial additional appro-
priations.
<0
f < J
Political Opposition
States (and specifically governors and state legislatures) will
need to consider carefully the political advisability of proceeding with
the establishment of an emission inspection program.
Present evidence is
fragmentary but seems to suggest that considerable political obstacles
may arise.
Chief executives in some jurisdictions, for example,
have attempted for many years to initiate state safety inspection
programs, only to be frustrated by strong rural interests in state legis-
1atures.
Indicative of these difficulties is the fact that in New Jersey,
a few months ago, letters to the State Air Pollution Control Agency were running
twenty to one against the proposed emission inspection program.
Contrar-
i1y, in California, where motor air pollution has been pe~'ceived as a
1. Initial investment costs for a state-owned and operated network of
vehicle inspection centers in California are estimated to be approximately
$12 million for idle, $19 million for key-mode and $88 million for
the diagnostic test routine. Northrop Corporation,Mand~tory Emission
Vehicle Inspection and Maintenance, Final Report (Anaheim, California:
Northrop Corporation in association with Olson Laboratories, Inc., 1971)"
p. VIII-l.
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1-26
large problem for sometime, 75 percent of motorists seem to support a
state emission inspection program (coupled with mandatory maintenance).
1
according to a recent survey.
Little can be said conclusively at this
point, but it appears that there will be substantial opposition from
many special interest groups (e.g., automobile owners associations,
advocates of highway construction, and so forth) to any program which
would require emission inspection on a regular basis.
Local Legal Authority
.,::'; ,
At the local level, similar issues of possible political opposition
will arise, should the chief executive and/or the local legislature decide
to move ahead with an emission inspection program.
In addition, there
may be serious legal shortcomings, as municipalities appear not to have
adequate legal authority to mount inspection, maintenance and retrofit,
depending upon the degree of "home rule" allowed under state law.
Other
legal problems (although of a different nature) will also arise where
important proportions of the motor vehicle traffic in a given jurisdiction
originate elsewhere (e.g., in Washington, D. C.
where approximately half
of motor vehicle traffic moving in the central city originates in Maryland
and Virginia).
1. Northrop Corporation, Mandatory Emission Vehicle Inspection and
Maintenance, Final Report (Anaheim, California: Northrop Corporation
in association with Olson Laboratories, Inc., 1971), p. III-I.
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1-27
Administering Agency
Assuming inspection programs are operated by some unit of state
or local government, a determination must be made as to the appropriate
administering agency.
Currently, the administration of motor vehicle
safety inspection programs varies considerably from state to state.
At the present time, the majority of jurt~dictions having safety in-
spection programs have mandated this resPQ~$ibility to the commissioner
of motor vehicles, but many other jurisdictions have assigned the task to
state police, to the state health department, to the state highway depart-
ment, to the state department of public safety, or to the state revenue
department.
Assignment of this responsibility will have an important
bearing on the ease of administration of emission inspection programs.
For example, motor vehicle agencies currently assigned the responsibility
of safety inspection programs, may, if assigned the responsibility of
emission checking, place higher priority on lane through-put than upon
provision for sophisticated measurements required by some regimes for
testing emiss.ions.
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CHAPTER
2
GASEOUS FUEL SYSTEMS
Definition of Terms
Within the near future (i.e., five years), only three types of
gaseous fuels can be seriously considered as alternatives to gasoline for
powering motor vehicles:
liquified petroleum gas (LPG). compressed natural
gas (CNG), and liquified natural gas (LNG).
These fuels are inherently
cleaner burning (produce fewer heavy hydrocarbonsl) than gasoline owing to
their lower molecular weight and carbon content.
In addition, gaseous
fuels ignite more rapidly and the combustion process proceeds more nearly
to completion leaving less unburned fuel in the exhaust stream.
Similar
levels of emission reductions result from conversion to either LPG or
2
natural gas.
Modification to gaseous fuel requires the installation of a special
carburetor (gas-air mixer~3 special fuel tanks (pressure tanks for LPG and
CNG, cryogenic tanks for LNG). pressure regulating devices, shut-off valves,
and fuel lines.
This is generally regarded as "simple" conversion as op-
posed to more sophisticated (and costly) modifications which may include:
installation of a special venturi carburetor (to allow lean air/fuel mix-
tures at low power levels and enriched mixture at high power operations);
1.
Heavy hydrocarbons contribute to the formation of photochemical smog.
2. Due to differences in hydrocarbon reactivity, the combustion products
emitted by natural gas powered vehicles are less conducive than LPG systems
to formation of photochemical smog.
3. Dual-fuel vehicles use the original carburetor in conjunction with an
adaptor.
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2-2
refined adjustment of engine variables; exhaust gas recirculation; exhaust
air-injection thermal reactor system; and a catalytic converter.
Vehicles
modified to this extent, however, would probably have emission levels sim-
ilar to those required by 1975 and 1976 for gasoline fueled operations
(and therefore would be of little advantage from a pollution control point
of view).
Consequently, we confine the following to a discussion of simple
conversion.
For simple conversion, the cost of modifying an in-use light-
duty vehicle to CNG or LPG ranges from $350 to $500, while conversion to
LNG may cost from $800 to $1000.
Liquified Petr0leum Gas (LPG)
Liquified petroleum gas (commonly referred to as propane) is a mixture
consisting mostly of propane and butane, with vapor pressures ranging from
100 to 300 pounds per square inch at normal ground level atmospheric tempera-
tures.
Due to its economic advantages, LPG has been used as a motor
vehicle fuel for many years and approximately 300,000 LPG powered vehicles
are currently in operation.l
LPG
is transported in com~ressed liquid form
by truck trailers and delivered to pressure storage tanks.
It is then easily
transferred as a liquid to vehicle storage tanks.
Handling procedures are
well known and relatively safe (odorants are available), and limited
quantities of LPG are available in urban areas throughout the country.
The
travel range of typical LPG vehicles designed for street use is approximately
220 miles.
1. The breakdown by vehicle (or engine) type is: industrial fork-lift
trucks 46.8 percent; farm tractors 25.0 percent; buses and tracks 15.6
percent; stationary engines 8.4 percent; automobiles 2.9 percent; and
truck refrigeration units 1..3 percent. Institute of Gas Technology,
Emission Reduction Using Gaseous Fuels for Vehicular Propulsion, Report
submitted to the Air Pollution Control Office, Environmental Protection
Agency (Chicago: Institute of Gas Technology, 1971), p. 4-38.
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2-3
Natural Gas
Natural gas (consisting primarily of methane) may be used in
compressed (CNG) form requiring heavy-wall, high pressure fuel tanks.
High pr~ssures (from 1000 - 2000 pounds per square inch) are necessary to
store sufficient CNG for reasonable travel ranges.
This in turn necessi-
tates a compressor at refueling points in order to boost local gas distri-
bution pressures.
Although natural gas is relatively safe (odorants are
available) from a flammability standpoint, the high pressures required
may constitute a significant hazard in the case of breakage or disconnection
of fuel lines or fittings.
Approximately 2,000 experimental vehicles
currently use compressed natural gas and a typical travel range is 70 miles.
Liquified natural gas (LNG) is currently being experimentally tested
in approximately 200 vehicles.
Unlike compressed natural gas, LNG must be
transported from special storage facilities or liquefaction plants to
refueling locations by LNG trucks.
The liquid is then transferred to
cryogenic vehicle storage tanks (no high pressures involved).
There is
currently no satisfactory odorant for LNG and therefore
leakage could be
hazardous.
A typical travel range for LNG vehicles is 240 miles.
Air Pollution Control Potential
In this and the following section, we consider four issues which
bear on the air pollution control potential of simple conversion:
(1) how
do emissions from LPG or natural gas powered motor vehicles compare with
emissions from gasoline power~d vehicles; (2) to what extent can any
area's motor vehicle population be converted to gaseous fuel in the short
term; (3) what would be the maximum realistically feasible reduction in
-------
2-4
emissions; and (4) what adverse side effects (from a pollution abatement
point of view) can be anticipated.
Emissions from Gasoline and Gaseous Fueled Vehiclesl
Accurate estimates of the emission reduction potential from simple
conversion are not possible with present empirical data.
These data (on
exhaust emissions from gAseous fueled vehicles) are extremely limited and
are based on a variety of different analytical test procedures and driving
cycles.
Moreover, the emission reductions achieved in each case are high-
ly dependent on the specific engine type, conversion equipment, and engine
adjustments.
In order to achieve the maximum emission reduction it is
necessary to "detune" the engine from manufacturers' specifications (e.g.,
ignition timing, fuel/air ratio).2
For these reasons, reported test re-
suIts vary considerably, and do not permit accurate predictions for in-
use vehicle populations.
Available data on individual vehicles, however,
do show that significant emission reductions can be realized by converting
pre-1975 cars to gaseous fuels.
Tables 2-2 to 2-6 show the range of values
1. The present discussion concerns primarily the emissions from indi-
vidual vehicles. A subsequent section, "Maximum Feasible Emission Reduction,"
discusses emission reductions for large fleets.
2. According to the California Air Resources Board, the special carburetor
to handle gaseous fuel must be carefully tailored to obtain low emission
results. Low emissions will not result by making conventional conversion
to these fuels, and this fact makes necessary the approval of these special
carburetors and modifications by the ARB. California Air Resources Board,
Reduction of Air Pollution by the Use of Natural Gas 0r Liquified Petroleum
Gas Fuels for Motor Vehicles (Sacramento, Calif.: California Air Resources
Board, 1970).
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2-5
which have been reported for conversion of various individual vehic1es.1
These reported results should be considered with reference to future
federal new car emission standards (see Table 2-1), which would require
even greater emission reductions than appear possible from simple conversion.
Table 2-1
FEDERAL EMISS ION STANDARDS FOR
LIGHT-DUTY VEHICLES
Carbon Monoxide
3.40 grams/mile
Hydrocarbons
0.41 grams/mile
Nitrogen Oxides
0.41 grams/mile
Source:
Federal Register, XXXVI, No. 228, Nov. 25, 1971, p. 22452.
Note: Standards for carbon monoxide and hydrocarbons are for 1975, for
nitrogen oxides 1976.
1. It should be stressed that the data presented for gaseous fuel systems
do not indicate the increase in emissions that would occur with accumulation
of mileage. Deterioration of emissions control efficiency is currently
being investigated by the EPA. Limited data obtained by the New Jersey
Department of Environmental Protection indicate that accumulated mileage
affects the emissions of gaseous fueled vehicles at least as seriously as
those of gasoline fueled vehicles. (Verbal communication to Michael K~aton
of Teknekron, Inc., October 14, 1971.)
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2-6
Table
2-2
EXHAUST EMISSION DATA FROM EPA
FOR GASEOUS FUELED VEHICLES
Vehicle Fuel Emissions in rams /mile
HC CO NOx
Converted 1968 Buick 350 LPG 3.5 4.7 8.9
Stock 1968 Buick 350 1.9 29.6 4.0
Converted 1969 Ford 351 LPG dual fuel 3.1 7.3 8.6
Stock 1969 Ford 351 7.4 37.8 5.2
Converted 1968 Ford 302 LPG dual fuel 2.4 4.2 1.8
Stock 1968 Ford 302 3.1 28.5 3.6
4 Converted 1969 Chrysler 318s LPG dual fuel 2.4 7.2 2.9
Stock 1969 Chrysler 318 3.4 30.5 3.6
2 Converted 1969 Rambler 343s LPG dual fuel 3.0 15.4 2.6
Stock 1969 Rambler 343 3.0 31.5 3.1
Converted 1969 Ford 429 LPG 1.3 4.0 1.9
10 Converted 1970 Ford 250s LPG 0.69 1.8 2.6
10 Stock 1970 Ford 250s 3.70 16.0 9.4
10 Converted 1970 Rebel 232s LPG .51 3.9 3.1
10 Stock 1970 Rebel 232s 2.7 22.1 6.9
2 Converted 1968 Chevrolet 230s CNG dual fuel .54 9.5
2 Stock 1968 Chevrolet 230s 3.7 58.2
2 Converted 1969 Ford 250s CNG dual fuel .46 7.8
2 Stock 1969 Ford 250s 2.6 25.3
Source: Merrill W. Korth, Test and Evaluation Branch, Federal Motor Vehicle
Pollution Laboratories, Environmental Protection Agency, Ann Arbor, Michigan.
Personal communication to Michael Keaton of Teknekron, Inc., December 20, 1971.
Note:
Blanks indicate no available data.
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2-7
Table 2-3
EXHAUST EMISSION DATA FROM IGT
FOR GASOLINE FUELED VEHICLES
Vehicle
Emissions in Krams/mile
HC CO NOx
1.
Average of 63 1964 and 1965 vehicles using
leaded gasoline.
2.
Average of 59 1964 and 1965 vehicles using
unleaded gasoline.
3.
1966 production small V-8 vehicles.
4.
1967 production vehicle with exhaust air
injection system for HC-CO control.
5.
Above vehicle modified with 15% exhaust
recirculation.
6.
1967 production vehicle equipped with
learner aarburetion and retsrded ignition.
7.
Same vehicle as (6) with modified carburetion
and ignition timing for reducing NOx emission.
8.
Same vehicle as (7) but with 15% exhaust
recirculation added.
9.
1966 V-8 air injection vehicle with optimized
jets and enriched carburetion, hotter spark
plug, retarded timing, and exhaust recycle.
10. 1967 V-8 air-injection vehicle equipped with
exhaust thermal reactor and enriched carburetion.
11. Above vehicle equipped with synchronized air
injection and further enriched carburet ion
during acceleration.
12. Same vehicle as (11) with 11% exhaust recycle
during partial throttle operation and tempera-
ture controlled enriched carburet ion during
acceleration.
13. Vehicle similar to (6) equippe~ with HC-CO
catalytic converter. At start of catalyst
durability test using unleaded gasoline.
Hot cycle data.
14. Above vehicle after 50,000 miles.
15. Vehicle similar to (4) equipped with NC-CO
catalytic converter. At start of catalyst
durability test using unleaded gasoline.
Hot cyc Ie da ta .
16. Above vehicle after 50,000 miles.
17. Assuming a NOx catalytic converter
capable of 707. emission reduction is
available and installed on vehicle (5)
equipped with HC-CO catalytic converter.
23.90 73.20
23.40 74;50
3.00 23.80
2.60 23.00
2.04 25.40
1.84 24.20
1. 70 19.00
1. 65 28.90
5.30
5.30
5.00
1.10
8.55
4.74
2.21
21. 10 2.19
23.20
6.20 0.48
2.01
0.70
6.50
0.33
2.80
0.50
0.80
Source: Institute of Gas Technology, Emission Reduction (sing Gaseous Fuels for Ve-
hicular Propulsion, Report submitted to the Air Pollution Control Office, Environment-
al Protection Agency (Chicago: Institute of Gas Technology, 1971), pp. 2-67 to 2-70.
0.72
3.40
Note: Some of the emission values ore estimated weight-based figures converted from
concentrations bv assuming 4000 lb. vehicle weight, and automatic transmission and
using the 1970 procedure (Federal Register, XXXIII, No.2, Jan. 1968). This calcu-
lation requires measurement of the emission conceatrations in the exhaust and then
assumes an average exhaust volume flow rate for each weight class of vehicle. While
this procedure on the average requires equal mass emission control for ~ifferent
size vehicles, it does not recognize the variation in the exhaust volume flow rate
for different vehicles in the same weight class. Blanks indicate no available data.
0.08
2.80
0.41
3.10
0.07
2.90
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2-8
Table 2-4
EXHAUST EMISSION DATA FROM IGT
FOR GASEOUS FUELED VEHICLES
Vehicle
Emissions in grams/mile
HC CO NOx
1. A 1966 6-cylinder vehicle, converted to dual-fuel
natural gas operation. California 7-Mode composite data,
converted from concentrations.
1.00
2.9
2. Average of 5 vehicles (1967,1~68, and 1969 models)
fueled with natural gas, with or without retarded ignition
and disconnected ignition advance. California 7-Mode hot-
start cycle. Converted from concentration values.
1.48
3.0
1. 01
3. Average of 7 vehicles (1968-1969 models having no emis-
~ion control devices) converted to gasoline-propane dual-
fuel operation. 1972 federal test procedure, cold start
data.
2.54
9.0
2.62
4. Average of 7 vehicles (model unknown) converted to pro-
pane, tested according to 1972 federal 9-CVS procedure.
2.75
5.5
4.26
5.
One of the 7 vehicles in (4), with 6-cylinder engine.
0.50
1.6
1. 20
6. A 1970 V-8 vehicle converted to propane, equipped with
variable venturi carburetor, lean air-fuel mixture, limited
distributor advance, disconnected vacuum advance, and in-
creased idle speed.
0.83
1.0
0.30
7. Above vehicle with a pair of catalytic HC-CO converters
added.
0.45
0.8
0.43
8. Vehicle of (7) with enlarged catalytic chamber and
slightly lowered compression ratio, hot-start data.
0.18
0.4
0.40
9.
Above vehicle, cold-start data.
0.49
1.1
0.53
Source: Institute of Gas Technology, Emission Reduction Usin Gaseous Fuels for Vehi-
cular Propulsion, Report submitted to the Air Pollution Control Office, Environmenta
Protection Agency (Chicago: Institute of Gas Technology, 1971), pp. 2-73 to 2-74.
Note: Some of the emission values are estimated weight-based figures converted from
concentrations by assuming 4000 lb. vehicle weight, and automatic transmission and
using the 1970 procedure (Federal Register, XXXIII, No.2, Jan. 1968). This calcula-
tion requires measurement of the emission concentrations in the exhaust and then as-
sumes an average exhaust volume flow rate for each weight class of vehicle. While
this procedure on the average requires equal mass emission control for different size
vehicles, it does not recognize the variation in the exhaust volume flow rate for dif.
ferent vehicles in the same weight class. Blanks indicate no available data.
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2-9
Table 2-5
EXHAUST EMISSION DATA FROM TRW
FOR UNCONTROLLED, CONTROLLED PRE-7l, AND NOx CONTROLLED VEHICLES
Emissions in grams/mile
Control Type 7-Mode Composite 1 72 Procedure Mass2
HC CO NOx HC CO NOx
Uncontrolled 6.9 66 4.4 (11.3) (122) (4.4)
-LPG (1.4) (8.4) (1.1)
-Natural' Gas (1.0) (17.6) (2.1)
Controlled, Pre 71 3.9 31 6.3 (7.1) (88) (6.2)
-LPG 0.7 4,,~ 1.1 (1.4) (8.4) (1.1)
-Natural Gas 0.5 8.6 2.1 (1.0) (17.6) (2.1)
1971 NOx Control ( l~ . 3) (51) (6.3)
Source: TRW Systems Group, Emission Factors for Motor Vehicles (McLean, Va.: TRW
Systems Group, TRW, Inc., 1971). Based on 24 LPG powered vehicles and 4 natural gas
powered vehicles. Parenthetical values are calculated equivalent mass emissions
from concentration data. Blanks indicate no available data.
1.
Federal Register, XXXI, No. 61, March 1966.
2.
Federal Register, XXXV, No. 136, July 1970.
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2-10
Table 2-6
EXHAUST EMISSION DATA FROM CALIFORNIA ARB
FOR GASEOUS FUELED VEHICLES
Vehicle
Fuel
Emissions in rams/mile
HC CO NOx
0.56 2.9 0.45
0.48 2.9 0.56
0.25 12.6 1.10
0.71 3.4 0.60
0.51 1.8 0.55
0.82 4.5 0.48
Chevrolet 1969
Chevrolet 1970
Oldsmobile 1965
LPG
LPG
LPG
Chevrolet 1968
Jeep 1969
Ford 1969
Natural gas
Natural gas
Natural gas
Source: California Air Resources Board, Reduction of Air Pollution by
the Use of Natural Gas or Liquified Petroleum Gas Fuels for Motor Vehicles
(Sacramento, Calif.: California Air Resources Board, 1970).
Extent of Conversion
In our view, the conversion of large numbers of motor vehicles
to gaseous fuels would be impractical or unwarranted in most major
metropolitan areas for the following reasons:
1. Natural gas is presently in short supply and no
major expansion in capacity is anticipated in the
near future. Low supplies of LPG combined with pref-
erential treatment for heating customers over fuel
customers have already caused a reduction in conversions
and loss of sales.
2. Conversion of large numbers of vehic les and imple-
mentation of an adquate fuel distribution system would
be extremely expensive.
3. Adequate supplies of cOnversion equipment are cur-
rently not available. Consequently, at least two to
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2-11
three years would elapse before significant numbers of
vehicles could be modified. 1
4. Considerable efforts are currently under way to
meet stringent 1975 federal emission standards through
modification of conventional gasoline engines. If
successful, these efforts would obviate the need for
gaseous fueled vehicles, which would be unable to meet
the above standards without engine modifications and
substantial supplemental equipment (e.g., thermal and/
or catalytic reactors).
In some metropolitan areas, however, fuel supplies, distribution
systems, and conversion equipment may be adequate for small-scale
conversions (e.g., commercial fleets).
Such conversions may be
warranted if (1) the vehicles to be converted account for a large
proportion of vehicle miles traveled in a relatively small area
(e.g., taxicabs in Midtown Manhattan); (2) the operations of these
vehicles are of a low-speed, stop-and-go nature (which normally results
in high emissions); (3) conversion could be effected rapidly so that
large numbers of pre-1975 vehicles are affected; and (4) the converted
vehicles would be regularly inspected and maintained.2
1. As indicated earlier, LPG is currently the gaseous fuel in greatest
use for powering vehicles (approximately 300,000 LPG powered units are cur-
rently in operation). Only a small fraction of these however (less than
9,000) are light-duty motor vehicles, a number less than even a single
fleet in one city (i.e., medallion cabs in New York City). Present pro-
duction figures are also low, Nationwide, the total annual production of
LPG carburetors is approximately 133,000 with only 12,000 sold on the East
Coast. Approximately 140,000 suitable LPG tanks are produced in the United
States and the number of LNG tanks produced is considerably less. Again,
however, only a small fraction of these units would probably be available
for powering light-duty vehicles. National LP-Gas Association, 1969 LP-Gas
Market Facts (1970).
2. It should be recognized that fleets generally have a much higher turn-
over rate than the general motor vehicle population. Consequently, the
proportion of pre-1975 vehicles in such fleets will decrease rapidly as
post-1975 vehicles become available. If investments in gaseous conversion
equipment tended to discourage these normally high turnover rates, the con-
version could be counterproductive from the viewpoint of air pollution con-
trol. (These observations of course assume that manufacturers of the new
gasoline powered engines meet the 1975 federal standards.)
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2-12
Maximum Feasible Emission Reductionl
Fleet and non-fleet medallion taxicabs produce an unusually large
percentage of total motor vehicle emissions in New York City.
In 1970,
for example, 14.8 percent of the total carbon monoxide emissions from motor
vehicles in Manhattan and 37.6 perceht of the motor vehicle
produced carbon
monoxide in the Midtown Central Business District were attributable to
medallion taxicabs.
Projections for 1975 (assuming full compliance with
federal new car emission standards) indicate 10.1 percent and 30.9 percent
for Manhattan and the Midtown CBD, respectively.2
Accordingly, conversion
of Manhattan taxicabs to gaseous fuels offers a good indication of the maxi-
mum feasible emission reduction for this control.
Table 2-7 summarizes the initial reductions in aggregate emissions
which are achievable from conversion of this motor vehicle population to
gaseous fuels.3
It is to be emphasized that these estimated emission
reductions represent control beyond that which is expected to occur as a
result of normal vehicle turnover rates and full compliance with federal
new car emission standards.
Table 2-7 shows estimated reductions as a per-
centage of total motor vehicle emissions; Table 2-8 shows estimates as a
percentage of aggregate (i.e., light-duty only) motor vehicle emissions.
Detailed calculations are presented in Appendix B.
1. This analysis is based on data from the New York City Environmental Pro-
tection Administration, Department of Air Resources, Proposed Plan for Meeting
Federal Air Quality Standards Relating to Carbon Monoxide, Hydrocarbons, Nitro-
gen Oxides, and Oxidants in New York City (New York: New York City Environ-
mental Protection Administration, 1972).
2. Motor vehicles account for 97 percent of carbon monoxide emissions in New
York City in 1970 and a projected 98 percent in 1975.
3. All estimates are for initial reductions and do not take into account deteri-
oration due to accumulation of mileage. By "emissions" we refer to carbon monoxide;
by "aggregate" emissions (or emission reductions) the carbon monoxide attributable
to light-duty motor vehicles in any given area; by "total" the carbon monoxide
emissions attributable to all motor vehicles.
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2-13
Table 2-7
MAXIMUM FEASIBLE EMISSION REDUCTIONS FROM CONVERSION TO
GASEOUS FUELS EXPRESSED AS A PERCENTAGE OF
TOTAL MOTOR VEHICLE EMISSIONS
Extent of Conversion
Carbon Monoxide
Emis s ion Reduc t ions 1
Borough of Manhattan
Conversion of all fleet and non-fleet medallion taxicabs
in the 1975 Manhattan taxi population.
Assuming 85.3% reduction from converted fleet vehicles
and 90.6% reduction from converted non-fleet vehicles.
8 . 8'70
Assuming 60% reduction from converted fleet and non-
fleet vehicles.
6.0%
Conversion of all fleet medallion taxicabs in the 1975
Manhattan taxi population.
Assuming 85.3% reduction from converted fleet vehicles.
5.4'70
Assuming 60% reduction from converted fleet vehicles.
3 . 8'70
Midtown Manhattan Central Business District
Conversion of all fleet and non-fleet medallion taxicabs in the
1975 Midtown Manhattan Central Business District taxi population.
Assuming 85.3% reduction from converted fleet vehicles
and 90.6% reduction from converted non-fleet vehicles.
27.1%
Assuming 60% reduction from converted fleet and non-
fleet vehicles.
113.5%
Conversion of all fleet medallion taxicabs in the 1975 Midtown
Manhattan Central Business District taxi population.
Assuming 85.3% reduction from converted fleet vehicles.
15.3%
Assuming 60% reduction from converted fleet vehicles.
10.8%
Source:
Appendix B.
1. Refers to reductions expressed as a percentage of emissions from all motor
vehicles in Borough of Manhattan and Midtown Manhattan Centr~ BusineSS-District
respective ly.
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2-14
Table 2-8
MAXIMUM FEASIBLE EMISSION REDUCTIONS FROM CONVERSION TO
GASEOUS FUELS EXPRESSED AS A PERCENTAGE OF
AGGREGATE MOTOR VEHICLE EMISSIONS
Extent of Conversion
Carbon Monoxide
Emission Reductionsl
Borough of Manhattan
Conversion of all fleet and non-fleet medallion taxicabs
in the 1975 Manhattan taxi population.
Assuming 85.3% reduction from converted fleet vehicles
and 90.6% reduction from converted non-fleet vehicles.
Assuming 60% reduction from converted fleet and non-
fleet vehicles.
13.0%
9.0%
Conversion of all fleet medallion taxicabs in the 1975
Manhattan taxi population.
Assuming 85.3% reduction from converted fleet vehicles.
8.1%
Assuming 60% reduction from converted fleet vehicles.
5.7%
Midtown Manhattan Central Business District
Conversion of all fleet and non-fleet medallion taxicabs in the
1975 Midtown Manhattan Central Business District taxi population.
Assuming 85.3% reduction from converted fleet vehicles
and 90.6% reduction from converted non-fleet vehicles.
58.7%
Assuming 60% reduction from converted fleet and non-
fleet vehicles.
40.2%
Conversion of all fleet medallion taxicabs in the 1975 Midtown
Manhattan Central Business District taxi population.
Assuming 85.3% reduction from converted fleet vehicles.
33.2%
Assuming 60% reduction from converted fleet vehicles.
23.4%
Source:
Appendix B.
1. Refers to reductions expressed as a percentage of emissions from light-duty
motor vehicles only in Borough of Manhattan and Midtown Manhattan Central Business
District respectively.
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2-15
The two values of "carbon monoxide emission reductions" estimated for
each case (Tables 2-7 and 2-8) correspond to emissions data from two inde-
pendenb sources and serve to demonstrate overall sensitivity of estimates
to varying assumptions about emission reductions from simple conversion
for converted vehicle populations.
The 85.3 percent reduction for fleet
medallion taxicabs and 90.6 percent reduction for non-fleet medallion
taxicabs correspond to a carbon monoxide emission factor of 5 grams/mile
estimated by the Institute of Gas Technology.1
The 60 percent reduction
in carbon monoxide emissions for fleet and non-fleet medallion taxicabs
is based on data from the New York City Implementation Plan.2
1. Estimated on the basis of simple conversion involving the installation
of gaseous fuel system, pressure regulator, air-gas mixer, blocked manifold
heat, and some minor adjustments of engine variables -- such as lean air/
fuel ratio, slightly retarded timing, increased idle speed, and disconnected
vacuum advance. Source: Institute of Gas Technology, Emission Reduction Using
Gaseous Fuels for Vehicular Propulsion, Report submitted to the Air Pollution
Control Office, Environmental Protection Agency (Chicago: Institute of Gas
Technology, 1971), p. 3-11.
It should be noted that this estimate is basically an "initial" emission
factor representing emissions from newly converted vehicles and does not
account for the possibility of deterioration in control efficiency (i.e.,
increasing emission factor) with accumulated mileage. There appears to be
no reliable data on control efficiency deterioration for gaseous fueled
vehicles.
2. New York City Environmental Protection Administration, Department of
Air Resources, Proposed Plan for Meeting Federal Air Quality Standards
Relating to Carbon Monoxide, Hydrocarbons, Nitrogen Oxides, and Oxidants
in New York City (New York: New York City Environmental Protection Adminis-
tration, 1972), p. 4-27.
Since the New York City Implementation Plan considered conversion of
fleet medallion taxicabs only, the 60 percent assumed reduction in per
vehicle emissions is strictly applicable only to fleet vehicles. However,
due to lack of specific New York City data on emission reductions for non-
fleet taxicabs, the 60 percent reduction is assumed to be applicable to both
fleet and non-fleet vehicles for the purposes of this calculation.
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2-16
It is important to note that these estimated emission reductions
do not necessarily imply a corresponding degree of improvement in ambient
air quality.
Localized improvements in air quality are in general rapidly
degraded by diffusion of pollutants from surrounding areas, a consideration
particularly pertinent to the Midtown Manhattan CBD.
Nevertheless, signi-
ficant improvements in street-level air quality in the vicinity of roadways
may be expected.
Finally, it should be stressed that conversion of all fleet and
non-fleet medallion taxicabs (almost 12,000 vehicles in operation) ap-
pears highly optimistic in view of the difficulties of inducing owners to
modify to gaseous fuel systems (see below "Institutional Feasibility").
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2-17
Institutional Feasibility
Earlier ("Extent of Conversion") we have a lluded to the inadequacy
of available fuel supp1ies,1 the high cost of installing conversion equip-
ment and implementing fuel distribution facilities for large
numbers of
vehicles and the presently limited production of conversion equipment.
For
these reasons, large-scale conversions would be impractical and unwarranted
in view of the considerable efforts currently under way to meet future federal
emission
standards through modification of conventional gasoline engines.
1. That natural gas is currently in short supply is commonly maintained
by both industry and government sources. (See. for example. "Gas Shortage
Poses a National Threat of Cutbacks." New York Times. November 21. 1971.
p. 1. and "Board Make It Official -- We Don't Have Any Gas to Spare."
Canadian Financial Post, November 27. 1971. p. 37). A recent staff report
of the Federal Power Commission covering the next 18 years suggests that
domestic production of natural gas is insufficient to meet expanding demand
after 1975. See, u.s. Federal Power Commission. Bureau of Natural Gas.
Natural Gas Supply and Demand, 1971-1990. Staff Report No.2 (Washington.
D.C.: Government Printing Office (FP 1.21:218). February 1972). This
nationwide picture, however, varies somewhat when we look at specific
areas.
In some heavily populated parts of the east, gas companies are refusing
to take on large new users, and even some residences. Similarly. some
government agencies have already moved to impose sweeping regulations on
gas consumption. Last fall. for example. New York State's Public Service
Commission required all utilities serving the state to reject all new in-
dustrial and commercial customers unless applicants could switch to alter-
nate fuels in an emergency or unless they engaged in industrial processes
that necessitated natural gas.
Conversely. some areas of the country are not so adversely affected.
For instance, a study prepared for the California Institute of Technology
concluded that supplies of CNG for the Los Angeles Basin are currently suf-
ficient to replace up to 25 percent of all gasoline burned in the area. See.
California Institute of Technology, Environmental Quality Laboratory, Smo~:
A Report to the People of the South Coast Air Basin (Pasadena. Ca1iL:
California Institute of Technology, 1972), p. 15.
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2-18
In some metropolitan areas, however, fuel supplies, distribution
systems and conversion equipment may be adequate for small-scale conversions
(e.g., commercial fleets) in highly polluted downtown (or other densely
Aside from possible technical difficulties,l the
developed) districts.
principal institutional problems in implementing small-scale conversions may
consist of (1) present safety regulations (at both state and local levels)
which discourage or preclude gaseoua fuels for motor vehicle use, (2) the
considerable costs and risks for fleet owners and operators of converting
to natural gas or LPG, and (3) the limited legal authority of municipalities
over large vehicle fleet owners and operators.
State and Local Safety Regulations
Safety regulations in some jurisdictions presently prohibit the
storage and/or transportation of gaseous fuels.
In California, for example,
any use of LNG requires approval of the State's Public Utility Commission,
while transportation of the gas (including LNG-powered automobiles) is
prohibited through some bridges and tunnels because of explosion hazards.
Similar regulations exist elsewhere in the United States.
1. Even for small-scale conversion the principal technical problem is fuel
distribution, since most metropolitan areas have very few fueling facilities
(aside from some stations now selling small quantities of propane to campers).
Installation, on the other hand, apparently presents no major problems ac-
cording to ongoing road testing (e.g., the General Service Administration's
dual-fuel experimental fleet), nor is performance adversely affected in any
appreciable way.
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2-19
These regulations, however, are often quite dated, in some instances
prescribing safety specifications now known to be unnecessarily stringent.
Until recently, for example, a New York City fire regulation drawn up
in 1913 prohibited storage of gaseous fuels in containers appropriate
for motor vehicle use. 1
Relaxing such regulations where they exist may
not present a large difficulty; the New York City Council, has now passed
a bill to permit storage of some gaseous fuels under certain conditions.
However, even if legal restrictions respecting storage are revised,
transportation may be a problem.
In New York City, for example, since LPG
presents some safety problems (e.g., the transportation of large quantities
through tunnels), Fire Department opposition has been sufficient to prevent
the tanking of LPG even though no law specifically prohibits the activity.
Similarly, New York City Fire Department safety standards (i.e., for stringent
compressor safety requirements) for natural gas may significantly raise the cost
and thereby discourage the use of natural gas as a fuel for fleets.
As a result,
the discretionary authority of some local agencies (e.g., fire departments
and bridge and tunnel authorities) may preclude or discourage the use of
gaseous fuels for motor vehicles even where regulations do not exist or
have been revised.
Costs and Risks of Conversion
The costs of conversion to fleet owner/operators fall into two
general categories:
(1) initial capital investments in both vehicle
conversion equipment (fuel tanks and lines, carburetor adaptors, etc.)
1. Present knowledge about the properties of gaseous fuels does not
dictate such stringent storage container regulations.
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2-20
and pumping apparatus (compressor and storage tanks). and (2) disruptions
to current operating practices (e.g., the need to develop new maintenance
techniques, fueling patterns and supplier relationships).
Benefits from
conversion may include longer engine component life, less downtime, lower
fuel costs (primarily due to state fuel tax savings) and (though
not a
direct cost saving to owner/operators) lower exhaust emissions.
At present,
however, little is known about the economics of conversion to gaseous fuels
since only a f~w small scale conversion programs have been implemented.
Lacking requisite data, we must confine the following discussion to several
of the most salient cost considerations, as well ~s the risks to owner/
operators inherent in conversion.
Conversion costs per vehicle range from $350 to $500 (for CNG or
LPG) to $800 to $1,000 (for LNG).l
Considerable costs are also involved
for CNG fuel compressors (approximate cost in excess of $10,000), storage
facilities for LPG and LNG (approximate cost of a 2,250 psi storage tank:
$3,200 plus installation costs), and filters.2
In addition, changes in
1. Institute of Gas Technology, Emission Reduction Using Gaseous Fuels
for Vehicular Propulsion, Report submitted to the Air Pollution Control
Office, Environmental Protection Agency (Chicago: Institute of Gas
Technology, June 1971), p. 6-10. Per vehicle conversion costs may depend
upon the number of vehicles undergoing conversion due to volume discounts,
(costs per unit decreases as fleet size increases), and whether conversion
equipment can be transferred to successive vehicles.
2. Ibi~, pp. 5-8 to 5-9. Financing conversion to gaseous fuels tends to
be easier for fleets whose vehicles are most intensively used (thus permit-
ting rapid amortization of high installation costs). These, in turn, tend
to be the larger fleets with newer vehicle populations (the bulk of vehicles
in large fleets are less than two years old). From an air pollution control
standpoint, however, fleets with older vehicles would gain more from conver-
sion to gaseous fuels. Ironically, those fleets which stand to gain the
greatest cost savings are also those which would contribute the least to
reducing emissions on a per vehicle basis.
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2-21
operation (e.g., new maintenance procedures and schedule~ may produce higher
costs, although absent approximate data, these cannot be estimated at the
present time. 1
These conversion costs may be retrievable from reduced operating and
fuel storage (for CNG) expenses.
Experience to date with converted vehicles
indicates that savings may include increases in the life of spark plugs and
exhaust systems, as well as fewer oil changes.2
What is more, fuel costs
per mile appear somewhat less for gaseous fuels, the differential depending
heavily on prevailing state fuel tax policy.3
While operating costs savings seem likely with conversion to
gaseous fuels, considerable uncertainty exists as to whether all capital
outlays involved in 'conversion can be recovered from reduced operating
1. Operating costs may be sensitive to
local fuel prices (including prevailing
size and type of fueling operation.
a number of variables including
state fuel tax policies), fleet
2. One source estimates maintenance savings from gaseous fuel conversion
at 7 percent. See Institute of Gas Technology, Emission Reduction Using
Gaseous Fuels for Vehicular Propulsion, Report submitted to the Air Pollution
Control Office, Environmental Protection Agency (Chicago: Institute of Gas
Technology, June 1971).
3. Tax incentives and other legislated inducements by guvernment bodies
can significantly alter relative fuel prices. In California, the 6~ per
gallon tax for LPG or LNG (l~ less than the corresponding gasoline tax)
and the 7~ per 100 cubic feet of CNG is waived if the fuel is purchased for
use in a properly tuned and certified (by the state's Air Resources Board)
motor vehicle.
Concomitantly, of course, loss in tax revenue could be considerable. The
California Institute of Technology's Environmental Quality Laboratory has esti-
mated that conversion of small fleets (trucks, taxis, buses and automobiles)
to gaseous fuels (25 percent CNG and 8 percent LPG) could result in a 33 percent
reduction in gasoline consumption. Based on the gasoline volume consumption
of 4 billion gallons for 1969. this represents an annual decrease of 1.3 billion
gallons or $143 million in annual state and federal tax revenue.
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2-22
expenditures.
(Again, the uncertainty arises primarily from the absence
of any large scale conversion experiments on privately owned and operated
fleets.)
As a result, fleet conversion seems a risky venture to fleet
owners.l
In addition to large initial capital outlays~ changes will have
to be made in long'standing operating/maintenance practices2 and supplier
relationships.
The reduced coverage of new car warranties may also be a
source of concern
to fleet owners; the warranty is void for any equipment
failure which can be traced to the installation and functioning of the
conversion system.
And, there is always the possibility that lacking a
well developed supply, distribution and marketing system, gaseous fuel
mcy become temporarily unavailable.3
1. Compounding the perceived risk of gaseous fuel conversions is the fact
that many fleet operators have lost confidence in the ability of one fuel,
propane, to meet operating requirements. Some conversions have been poorly
designed and even units designed specifically for propane have not always
been satisfactory. For example, the Chicago Transit Authority operates the
largest propane-fueled bus fleet in the world, but has not purchased any
additional propane units since 1963. This is primarily due to the inavail-
ability of equipment specifically designed to run on propane, but in addition
the CTA does not wish to install engine conversion kits.
2. In California, for example, maintenance
insure that vehicles are properly tuned for
for the waiver of gaseous fuel taxes.
schedules must be arranged to
~ow emissions, a pre-requisite
3. Even if supply shortage problems can be overcome, distribution may also
pose certain difficulties. In 1.os Angeles, for example, only some 50 service
stations presently sell propane fuel (plus another 40 who sell propane to
campers) and no such distribution system exists for natural gas (two pilot
programs have recently been announced by the Union Oil Co. and the Pacific
Lighting Corporation to be run in Riverside, Californta). See, California
Institute of Technology, Environmental Quality Laboratory, Smog: A Report
to the People of the South Coast Air Basin (Pasadena, Calif.: California
Institute of Technology, 1972), p. 15. The usual practice is for CNG-
converted fleets to have their own fueling facility, including a compressor
and storage tank. However, since such equipment is costly and probably
beyond the financial capabilities of small fleet operators, it would
probably be necessary to provide some type of distribution infrastructure
before requiring private fleet conversion.
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2-23
Finally, and perhaps most important, there is the short time interval
before 1975, at which time new car emission standards require emissions to
be at least as low as current converted vehicles.
Given the substantial
initial costs and risks associated with conversion to gaseous fuels and the
large proportion of new vehicles most fleet owners purchase each year, fleet
owners would doubtless resist strongly any governmental attempts to require
fleet conversion as a short-term air pollution control measure.
.Legal Authority
In mast cities, adequate legal authority to require fleet conversion
does not appear to be a major problem, particularly in the case of taxis
(usually already subject to government regulation).l
Since most jurisdictions currently inspect their taxicabs periodi-
cally for safety criteria (usually through the local Bureau of Motor
Vehicles) and since most city councils have the legal authority to regulate
taxis (through ordinances), adequate authority exists to require and enforce
taxi fleet conversion to gaseous fuels.
The main problems are less likely to
be legal than political:
the resistance by powerful taxi fleet owners.
1. The governmental agency which regulates taxi operations varies from
jurisdiction to jurisdiction. Often the city council is the predominant
authority, either directly or indirectly. In New York, the City Council
is the chief promulgator of regulations for the taxicab industry, but its
regulations are enforced by the Taxi and Limousine Commission. In the
Chicago and Washington metropolitan areas, several governmental agencies
have authority over the industry, and depending upon the area involved,
are often subject to local city council approval. In the majority of cases,
the taxi industry is regulated by municipal agencies through local ordinances
(although some states regulate their taxis through the state public utilities
commission).
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2-24
Taxi owners in large metropolitan areas are commonly organized in some
form of association and as a result, their ability to forestall regulation
(e.g., mandatory conversion) may be significant.
The natures of local
taxi industries (as well as of regulatory podies) varies considerably, of
course,
and thus it is not possible to predict at this time the way poli-
tical opposition might arise.
However, if experience from other areas of
government regulation is any indication, industry resistance may express
itself in many ways.
Industry representatives may persuade the regulatory
body on the basis of studies or "expert witnesses" that regulation would
be so burdensome or costly as to preclude even consideration in the form
of hearings or research.
Or the industry may prolong hearings by repeatedly
raising new issues or generating public concern.
Or industry representatives
may simply await the completion of all public proceedings and then file for
a court injunction to suspend further action.
-------
CHAPTER
3
TRAFFIC FLOW TECHNIQUES
Definition of Terms
As used in this report, "traffic flow techniques" refer to those
traffic engineering measures that have as their principal objective a
reduction in delays, idling periods and stops and starts which, in turn,
1
would tend to increase average vehicle speeds on the existing street
2
sys tern.
In considering traffic flow techniques, it is desirable to keep
in mind the hierarchy of facilities -- ranging from freeways to arterials
to local city streets3 -- that service large metropolitan areas.
Depending
1. A secondary result of some traffic flow techniques (e.g., ramp meter-
ing, prohibition of on-street parking) may be to reduce vehicle volumes
along given roadways. Measures to this end are considered in Chapter 6
on "Motor Vehicle Restraints." For purposes of the present chapter, how-
ever, we focus primarily on the objective of increasing the speed at which
traffic flows. The term traffic flow as it is generally used in traffic
engineering includes not only the "quantity" aspects of the word flow
(i.e., vehicle volumes at given speeds), but also the "quality" aspects
(i.e., the uninterrupted character of the flow). From an air pollution
control point of view, the quality can be as important as the quantity,
since motor vehicle emissions are a function of both average vehicle speeds
and stops and starts. It is in this latter sense (i.e., both quality and
quantity) that "traffic flow" is used in this report.
2. Because of the short time frame for this study, emphasis here is upon
improving existing facilities, not new construction. Construction of new
urban highway facilities is a time-consuming practice which would involve
the entire metropolitan planning, funding and implementation process.
Consequently, major changes would not be possible within five years.
3. As commonly used, "freeways" refer to highways with full control of
access, with all intersections fully grade-separated. Typically, freeways
accommodate large traffic volumes at high speeds. "Arterials" refer to
those streets either divided or undivided that have the main function of
carrying "through" traffic at medium speeds. "Local streets" refer to
streets that have the main function of providing access to adjacent prop-
erties, and are not intended to carry "through" traffic.
-------
3-2
on which type of facility is improved, traffic flow techniques offer
differing potentials for air pollution control.
For example, because of
their grade-separated characteristics urban freeways afford the potential
1
for higher average vehicle speeds than any other parts of the street system.
Also implicit
in their design is the objective that no stopping is required
(assuming loading at design volumes and normal Dperating conditions).
Be-
cause access is controlled, some traffic flow techniques (e.g., ramp meter-
ing) can be used to control the volume and lane density of vehicles on the
facility.
Arterials and local streets, on the other hand, are characterized
by frequent grade intersections, sometimes unrestricted midblock access
and traffic signals.
Traffic on arterials and local streets is also re-
1ative1y more susceptible to interruptions by pedestrians, truck deliveries,
parking and transit buses than is freeway traffic.
All of these factors
result in friction that causes relatively lower vehicle speeds and more
stops-and-starts.
Furthermore, the potential for pollution control from
smoothing traffic flow in downtown areas is limited in many instances
(e.g., widening intersection approaches) by the already densely developed
nature of the central business district (CBD).
Usually, it is on or near
these 'downtown facilities where the highest traffic and population densi-
ties are found, and where emission reductions would be most required.
More will be said on these matters in the "Air Pollution Control Potential"
section of this chapter.
1. However, as discussed below, because of the speed/emission relation-
ship the higher ranges of freeway speeds (as well as their relatively free
flow) may be less relevant to air pollution control than the low average
vehicle speeds and stop-and-go traffic characteristic of arterials and
local streets.
-------
3-3
Traffic flow techniques appropriate for the existing streets fall
into four categories:
(1) modification of street use, (2) increases in
effective facility size, (3) pedestrian controls, and (4) traffic controls.
These categories are listed in an approximate order of the complexity of
making changes.
For example, street-use modifications include lane markings
which involve paint and manpower, whereas traffic controls range from
traffic signals to c~puterized control and surveillance systems which re-
quire complex equipment, construction and planning.
In this section we
discuss the most relevant traffic control techniques in each category,
summarize the salient experience, and identify the major results from a
transportation point of view.
In sub~equent sections, we assess the air
pollution control effect of these techniques and their institutional feasi-
bi1ity.
Differing policies for different vehicle typesl are considered in
more detail in the chapters on motor vehicle restraints and improvements
in public transportation.
Modification of Street Use
A variety of techniques may be employed to modify use of the street
system.
For example, streets may be modified to carry traffic in several
alternative arrangements, depending on demand by time of day.
These al-
ternative arrangemertts may involve changing the direction of flow, or the
number o.flanes in each direction, controlling turning movements, modi-
fying traffic patterns at intersections, and so forth.
Details are sum-
marized in Table 3-1.
1. For example,
to prolong green
of buses on city
bus priority systems (e.g., programming traffic signals
time for loaded buses) could be used to improve the flow
streets.
-------
Table 3-1
(page 1 of 3)
MODIFICATIONS IN STREET USE
Technique
Experience
Description
One-way streets
Reversible lanes
and streets
Traffic flows in one direction only.
Adjacent streets are paired so as to
serve both directions of travel.
Primary purpose is to eliminate con-
flicts between left turn and through
vehicles at intersections, eliminate
conflicting requirements of opposing
traffic, and make possible more effi-
cient signal progression. However,
one-way street systems also entail
longer trips for some vehicles, make
some transit service less desirable,
and can often confuse motorists by
requiring irregular routing.
One or more lanes are designated
for movement in one direction dur-
ing one part of the day and the
opposite direction for another part
of the day. Technique is applicable
to bridges, tunnels and wide arterials.
It is possible on freeways if so
designed and constructed.
Widespread use in many American cities.
One-way operation is most desirable where
large turning movements conflict with two-
way operations, where signals are closely
spaced (making two-way signal progressions
impossible) and where directional distri-
bution of flow is fairly balanced during all
time periods of the day. Hence, one-way
street systems are particularly suitable to
downtown areas characterized by large volumes
of circulating traffic and closely spaced
intersections. Primary purpose is to meet
short term, highly directional traffic demands
experienced in many metropolitan areas during
periods of peak traffic flow and to provide
for more efficient use of facilities.
W
I
~
Presently used for many arterial operations
including Boston, Chicago, Cleveland, Detroit,
Los Angeles, and Washington, D. C. Also
used in many American cities to improve
arterial operations to utilize existing
facilities for more capacity.
-------
Table 3-1
(page 2 of 3)
Technique
Experience
Description
Turning movement
controls
Median Controls
Signs and pave-
ment markings
Variety of methods may be em-
ployed, ranging from prohibi-
tion of turning at peak hours
to provision of special right
and left turning lanes at all
times. Primary purpose is to
prevent delays behind turning
vehicles and hence to smooth
traffic flow.
Widespread use on arterials in
most American cities.
Structural or painted length-
wise division of a two-way
street, arterial or freeway.
(Not~: additional space can
sometimes be achieved by pro-
hibiting parking on one or both
sides of the street.) Primary
purpose is to reduce mid-block
friction by preventing mid-block
left turns and U turns.
Widespread use on arterials; some on
local streets in American cities.
IN
I
V1
Provide drivers with advisory in-
formation to permit better selection
of existing facilities. Techniques
include: (1) street signs, (2) longi-
tudinal pavement markings; (3) trans-
verse pavement markings (i.e., to
indicate stopping locations) and
pedestrian safety areas, (4) guide
signs (i.e., to indicate upcoming
turns, exits and so forth), and
Widespread use on freeways, arter-
ials and local streets in American
cities.
-------
Table 3-1
(page 3 of 3)
Technique
Description
Experience
Signs and pave-
ment markings
(cont'd)
(5) driver advisory information
displays (i.e., to advise of freeway
traffic conditions and encourage
use of alternative routes in times
of congestion. )
Channelization
Direction of traffic into appropriate
lanes so as to assure smooth flow of
merging and diverging streams. Sim-
plifies turning move!!lent conflicts
and permits more effective signal con-
trol.
Currently in use in many American cities
where street systems are characterized by
non-grid configurations, many opportunities
are available for reducing traffic conflicts
at intersections.
!..>
I
'"
-------
3-7
Increases in Effective Facility Size
In many instances, the full width of urban streets is not effec-
tively utilized for traffic movement with the result that congestion and
accompanying air pollution are exacerbated.
For example, it has been
established that the usable width of an intersection approach has the
greatest bearing on the capacity of that approach.
Thus, for purposes
of smoothing traffic flow, wide lanes are preferable to narrow ones, and
in most instances three wide lanes will carry as much traffic as four
narrow ones.
Many cities, however, still use narrow lanes.
For increasing effective facility size within the time frame of
this study (i.e., within five years), there are two major possibilities:
(1) restricting on-street parking, and (2) widening intersection approaches.
(Widening intersection approaches, it should be noted, is often impossible
on downtown local streets where development is already dense; however, on
many arterial streets widening intersection approaches is frequently pos-
sible with minor construction.)
Details are summarized in Table 3-2.
Pedestrian Controls
do the characteristics of pedestrian traffic itself~
Current practice regarding pedestrian controls varies widely, as
. ii
Although traffic
engineers agree in principle that pedestrians and vehicles should not mix,
practical and economic considerations prevent such total separation.
How-
ever, pedestrians must be accommodated and protected.
In view of the
volume of pedestrian traffic in most urban areas (and especially in the
six cities considered for this study), very few alternatives have been
-------
Table 3-2
INCREASES IN EFFECTIVE FACILITY SIZE
Technique
Description
Experience
Curb-lane controls
Widening of street
within existing
right of way; wid-
ening approaches
to intersections
Controls would prohibit curbside park-
ing and/or standing, and could apply
generally, in critical areas, or dur-
ing specified periods.
Section of street cut out between in-
tersections or at approaches. The
former provides facilities for load-
ing and unloading passengers and goods,
thus reducing mid-block frictions and
removing impediments to traffic flow.
The latter facilitates traffic flow
through intersections.
In many cities, curbside parking is
presently restricted on arterials
during peak traffic periods. Extent
of enforcement of this prohibition,
however, varies considerably from city
to city.
Currently in use for bus stops,
stands, and sometimes for truck
Widespread use in many American
taxi
loading.
cities.
-------
3-9
considered to existing arrangements (i.e., principally crosswalks at
intersections).
Indeed, many sweeping renewal projects in downtown areas
seem to ignore the problem, and few have made any provision for adequate
separation of facilities.
Pedestrian overpasses have become an essential
part of many expressways and mass transit improvements, but most downtown
arterial applications have been makeshift in character.
Pedestrian pro-
hibitions and controls are generally difficult to enforce.
In some downtown areas, pedestrian malls and similar installations
have contributed to removing pedestrians from arterial intersections.
No
comprehensive program of pedestrian controls has been implemented as yet
in any American city.
Consequently, crosswalks at intersections are still
the standard provision for the interfacing (and hence the interfering) of
pedestrians and vehicles. 1
Details are summarized in Table 3-3.
Signalization2
Traffic signals are probably the single most important measure to
improve traffic flow.
Their commands are unquestionably obeyed.
One
1. At signalized intersections, the accommodation to pedestrians in their
relatively slow pace of approximately four feet per second is an a priori
constraint on signal timing. Depending upon demand, pedestrians are
accommodated in various ways. For example, light p~destrian traffic may
be handled safely with simple crosswalks, if clear stop-and-go signs or
other indications are visible to pedestrians. Heavy pedestrian traffic,
in turn, may be accommodated through provision of actuated concurrent
pedestrian phases and pedestrian indications. A number of other possibili-
ties are available, of course, depending upon vehicle controls, volumes
and pedestrian demand.
2. Broadly defined, signalization encompasses
intersections, timing of iritervals, allocation
enforcements and offsets.
phasing and sequencing of
of green time, progression
-------
Table 3-3
PEDESTRIAN CONTROLS 1
Techniques
Description
Experience
Crosswalks
Range from the "standard" crosswalk,
whereby pedestrians cross streets on
green light and/or "walk" signal, to
mor~ sophisticated systems (e.g.,
exclusive pedestrian phase coordinated
to provide selectable vehicular pro-
gression between the adjacent signalized
intersections).
In widespread use in American cities
of all sizes.
Overpass/Underpass
Permanent pedestrian walkways con-
structed over roadway.
Often used over urban freeways and
arterials.
W
I
......
o
Barriers
Permanent fence or posts with con-
necting chains located near the
edge of sidewalk.
Limited use in some downtown areas
of American cities.
Bi-level Development
Promenades, pedestrian walkways,
galleries, etc.
Atlanta, Philadelphia, Minneapolis.
1. Experience with pedestrian malls and various vehicle-free zones is summarized in Chapter 6,
"Motor Vehicle Restraints."
-------
3-11
recent study of eleven experiments with signal controls (five involving
single intersections and six involving coordination of signals on arterials
or in networks) concluded that:
The signal system of a downtown area is the most
important element of all the control media avail-
able. Very minor changes of signal timing pro-
duced large improvements to traffic flow. Many
other types of improvements should be considered
subservient to the needs of the signal system.
Among these are restrictions to parking at inter-
section approaches, locations of bus stops, pro-
vision of separate left-turn lanes, mandatory
lane use, and channelization -- all of which.
at least to some degree, are involved in opti-
mizing the sign~l system. The ability to organ-
ize successfully progressions depends largely on
the reduction of frictions by use of these other
control media. 1
In conventional practice, most signal systems are not computer
controlled; their operational programs are predetermined and based upon
estimates of flow, historical data, averages and observations.
Given the
requirement that cross-traffic on city streets be accommodated, the potential
for improvements with a modern signal system is substantial.
As one recent
survey of the state of the art noted:
Everyone has experienced frustrating stops
at traffic signals that appear to be needless
because nobody on the other street is using
the intersection either, anq everyone has been
caught in huge queues on the approaches to . .
signals.
1. Highway Research Board, National Cooperative Highway Research Program
Report 113, Optimizing Flow on Existing Street Networks (Washington, D.C.:
National Academy of Sciences-National A~ademy of Engineering, 1971)~p. 3.
-------
3-12
Because of the ubiquity of these situa-
tions, and because, even in the most freeway-
oriented cities, upward of 60 percent of all
travel is on streets that have traffic signals,
any improvement in timing the red and green 1
intervals would have an enormous payoff. . .
However, the same survey notes:
. . . there is nothing on the horizon that
will justify statements to the effect that
electronic surveillance and high-speed com-
puters can eliminate congestion in urban
areas, or 'double t2e capacity' of the sur-
face street system.
In fact, the authors warn:
It should be noted that the maximum increase
in throughput attainable by any control
method (ramp metering or otherwise) cam,ot
exceed the amount by which present through-
put [throughput is defined as the ~ of
accommodating vehicle-miles of travel] is
less than capacity. There are very few miles
of freeway in the U.S. Where this difference
is more than 10 to 25 p~cent, and even there,
only during peak hours.
1. Highway Research Board, National Cooperative Highway Research Program
Report 84, Analysis and pro;ection of Research on Traffic Surveillance,
Communication and Control (Washington, D. C.: National Academy of Sciences-
National Academy of Engineering, 1970), p. 2.
2. Ibid. In view of What might be considered a lagging state of the art in
the application of modern signal systems, the computer affords additional
advantages. The traffic engineer with a well-designed, computer-controlled
system will be able' to"p{itSu~ his" are more e:ffective1y, and will be able to
experiment and to evaluate his experiments. Furthermore, the equipment
can be set up to maintain surveillance over itself so that hardware mainte-
nance and adjustments are simplified. Finally, the computer can facilitate
implementation of the improvements that will inevitably result from ad-
vances in the technology of traffic control.
3.
Ibid.
-------
3-13
The potential for Lmproving traffic flows through the use of
computerized traffic signals is probably substantial.
In one large city
where computer-controlled traffic signal timing tests were conducted,
reductions in travel tLme ranged from 26 to 39 percent and reductions
in the number of stops ranged from 60 to 86 percent.
In another city,
network
delays were reduced by 14 percent and the probability of a vehicle
being stopped was reduced by 17 percent.
In a medium-sized city, delays
were reduced 18 percent and peak hour average speeds were increased between
10 and 15 mph.1
From city to city, however, the room for improvement varies widely,
depending largely upon the base-line operating characteristics of the
street network before computerization.
If the original signal system is
already based on ski1fu11y engineered traffic control programs, it is
entirely possible that little or no traffic flow improvements would be
possible.
In addition, the gains from computerization are apt to be
large at the outset of the program when the "programming" capacity of the
computer makes initial (and in a relative sense easy) Lmprovements possible.
However, after these initial gains, the range of possibilities will narrow
and improvements will rest on the imagination and skill of the traffic
engineer -- not on some inherent quality of the computer.
,,~ ,,,>, ,,,
1. Information derived from Highway Research Board, National Cooperative
Highway Research Program Report 84, Ana1vsis and Proiection of Research on
Traffic Surveillance, Communication and Control (Washington, D. C.:
National Academy of Sciences-National Academy of Engineering, 1970).
-------
3-14
Air Pollution Control Potential
Simply stated, motor vehicle exhaust emissions (carbon monoxide and
hydrocarbons) are lower in freely-flowing traffic than in congested, stop-
and-go conditions.
There is some evidence that the converse holds for
nitrogen oxides (i.e., that NOx emissions increase with increased vehicle
1
speeds).
Assuming an established relationship between emissions and speed,
what increases in average vehicle speeds and accompanying carbon monoxide
reductions can be anticipated from traffic control and flow improvements?
Straightforward as this question may seem, a simple answer is not easily
given because of a number of complicating factors discussed below.
Site-specific Nature of Improvements
From a pollution viewpoint, the degree of potential improve-
ment depends in large measure upon the baseline speeds prior to imp le-
mentation of traffic flow techniques.
For example, increasing average
vehicle speeds from 5 to 10 miles per hour is much more important from an
air pollution control point of view than increasing average vehicle speeds
from 25 to 30 mph.
In turn, baseline speeds depend upon such factors as
the physical characteristics of the urban street network under considera-
tion, the existing traffic volumes and available capacity, anticipated
growth and so forth.
All of these factors are city (site) specific and
must be so treated.
1. This general statement, however, ignores a number of important com-
plicating considerations which are treated in Appendix C of this
report.
-------
3-15
Facility Evaluation vs. Network (System) Evaluation
Any accurate evaluation of the impact of traffic flow improvements
must take into account network (system) repercussions, i.e., those re-
percussions which extend beyond the specific facility being improved.
Unfortunately, however, most available data as to the impact of potential
improvements are for specific facilities and not for entire networks.
It
may be highly misleading to consider an improvement strictly in terms of
the specific facility.
For example, installation of one-way streets can
greatly improve the speed of traffic along the specific roadway in
question, but there are offsetting disadvantages in that longer trips may
1
be required by many motorists and vehicle miles traveled could increase.
Similarly, traffic using one-way streets might well be but a tiny fraction
of vehicle volumes for the system as a whole.
Hence, any prospective
one-way system for air pollution control purposes should be studied in
terms of its impact upon the entire street network.
System-wide evaluations should also consider larger areas than
would be required for specific facility improvements.
In addition, longer
time periods (perhaps several years in some cases) would be needed so as
to allow for all secondary and tertiary repercussions and adjustments to
work themselves out.
For example, it is well established that increased
travel speeds (and therefore shorter triptimes) eventually generate longer
trips.
Therefore,a consequence of improved traffic flows (absent motor
1. To evaluate the air pollution control potential of a one-way street
system, a traffic assignment model (i.e., one which models the motorist's
route selection between two points or a set of points) must be prepared
to determine whether increases in speed or increases in vehicle miles
traveled would be the dominating factor.
-------
3-16
vehicle restraints) could well be higher vehicle miles traveled with
accompanying greater (though perhaps more .dispersed) emissions.
Annual Traffic Growth
Annual growth in the volume of urban traffic is usually considered
to consist
of two components:
(1) a long-term trend associated with
rising incomes, population and motor vehicle ownership, and (2) "induced"
or "generated" travel which results from the provision of some improvement
(e.g., comfort, convenience, reduced trip time) or added capacity in the
1
street or highway network.
Both components of annual traffic growth can
be i.llustrated with data drawn from cordon counts taken for Chicago and
Washington, D.C.
The long-term trend of traffic growth into and out of the Chicago
CBD is shown in Figure 3-1.
From a total (entering and leaving) of about
324,865 vehicles in 1946, traffic in 1971 reached 470,563 -- an annual
average growth rate of 1.5 percent.
Another example of long-term growth
and induced traffic is illustrated in Figure 3-2 with traffic data for
Washington, D.C.
The figure shows annual passenger vehicle traffic volumes
on the major Potomac River crossings from 1965-70.
From 1965 through 1970,
inbound passenger vehicle traffic at all Potomac River bridges increased
from 136,892 to 174,171 -- an average annual increase of about 5.0 percent.
1. Other kinds of analysis which may be considered are hourly (particu-
larly for peak periods), daily (e.g., work days and weekends) and seasonal
variations. It is conceivable that tTaffic flow improvements by attracting
more traffic (i.e., induced travel) could increase peak hour traffic volumes
on the existing street systems. The increased volumes could eventually
result in a return to former average speeds but with higher traffic volumes
and therefore higher levels of emission than existed before the traffic
flow improvements were in place.
-------
Figure 3-1
DAILY NUMBER OF VEHICLES ENTERING AND LEAVING THE CENTRAL BUSINESS DISTRICT OF CHICAGO
BOUNDED BY ROOSEVELT ROAD, LAKE MICHIGAN AND THE RIVER
7:00 A.M. TO 7:00 P.M. TYPICAL WEEKDAY IN MAY 1935 to 1970
300
100
Lake Shore Dnve Included
-
"""' ..... ~ ~ ,..... ~
...... ~
~ r- .n.
~ ,~" " , "'" 1'""
~ ,...., '" ~ '- .."
~ ,,",' ~ " , ~
~ ~, ~ .."
EN !RI~ ~ ,..1 ~ ~ ..
.." ~ "
-.". '"::" " ,"
-01IIII
~ ".". l1li""'" """"'III l1li""'" .." 6)
~ ,~" -,"" Inll ~" L AVI~
~" 11'-'
~ -- ,,"14
~ II~' un, ,..
~ ~ ~
" "::. ..
~ ' !I'u:
~ ~
'
".." \
.......
~
~ !JIII ::-
~'f~
'=
W
I
~
--.J
250
If)
o
z
CI
If)
=>
o
~ 200
~
If)
...
-'
~
:%:
...
>
~ 150
II'
...
CD
~
=>
z
o.
1935 '36 '37 '38 '39 '40 '41 '42 '43 '44 '45 '46 '47 '48 '49 '50 '51 '52 '53 '54 '55 '56 '57 '58 '59 '60 '61 "62 '63 '64 '65 '66 '67 '68 '69
Source:
Chicago Bureau of Street Traffic, 1970 Cordon Count:
Central Business District
-------
3-18
Figure 3-2
WASHINGTON D.C. CORDON COUNTS-POTOMAC RIVER BRIDGES
12-HOUR INBOUND VOLUMES
(6:00 A.M. - 6:00 P.M.)
1965-1970
1969
1970
-------
3-19
In the long term, as new capacity is added to the street and road
network, traffic growth results from the long-run forces of rising incomes,
population growth and increased levels of motor ownership shown in Figures
3-1 and 3-2.
However, because in the short run (say within a period of
three to five years) the available street capacity is relatively fixed in
most large urban areas, peak-hour capacity is usually saturated with traffic
(i.e., congestion).
Cordon count data for Chicago (Figure 3-1) suggest that
as streets providing access to the Chicago CBD become saturated, congestion
acts as a restraint to the use of the automobile (thus, the slower rate
of increase from 1963 to 1970).
In Figure 3-2 for Washington, D.C., the
~olume of traffic remains relatively stable (increases, but very slowly)
except when there are changes in the form of either added capacity or im-
provements in existing capacity.
These changes could result in higher
speeds and/or shorter travel tinles; the latter, in turn, could generate
new trips until once more congestion acts as a constraint on the use of
the automobile.
Analysis of the data in Figure 3-2 shows that with tpe opening of
the Theodore Roosevelt Bridge in June 1964, traffic was probably diverted
from Key Bridge (already characterized by congested conditions).
However,
the combined Potomac River crossing traffic continued to grow with the
availability of additional bridge capacity.
An illustration of the induced travel which can result from new
capacity may be found in a study of the impact of alicago's Congresss
-------
3-20
1
Street Expressway on arterial and local streets in the area.
1be study
(a "Before" and "After" [1959 and 1961J examination of the traffic within
a 16-square mile area around the expressway) noted that there was a 21
percent increase in total vehicle-miles of travel within the study area
over the two-year period -- an annual rate of increase which was three
times the normal Chicago increase of 3.5 percent a year or 7 percent for the
two-year period under study.
'lhus there was a growth of about 14 percent
over what was considered normal for Chicago based on traffic counts made
in 1953, 1956 and 1959.
Although a part of this 14 percent difference
was probably traffic attracted from outside the study area, some of the
increase was doubtless due to "induced" travel which would not have oc-
2
curred in the absence of highway improvements.
In most urban areas, there exists a condition of "capacity
satu-
ration" especially during the peak hours when the demand for access to
work is highest.
This capacity saturation results in latent or "pent-
up" demand which can manifest itself in added trips whenever new capacity
is provided or improvements result in improved travel times similar to
1. See Frederick F. Frye, "The Effect of an Expressway on the Distribution
of Traffic and Accidents," (paper presented at the 42nd Annual Meeting of
the Highway Research Board, Washington, D.C., January 1963), cited in
J.R. Meyer, J.F. Kain, and M. Woh1, The Urban Transportation Problem (Cam-
bridge, Mass.: Harvard University Press, 1965), pp. 77-78. The net
amount of the 14 percent which might be attributable to "induced" traffic
is not clearly stated.
2. Meyer, Kain and Woh1 (Ibid.) suggest that ''most of the difference is
probably a result of traffic attracted from arterial and local streets out-
side the 16-square mile study area" (p. 77) but do not present data to
support this conclusion.
-------
3-21
added capac i ty) .
This latent demand accounts to a considerable extent
(though not entirely by any means) for What is known as induced or
generated trips.
the rapidity with whiCh traffic builds up in response to new
or Unproved facilities will depend on many factors including the existing
traff~c density on the present street network (i.e., the extent to Which
the streets are saturated).
However, even Where capacity saturation is
found, overall traffic volumes in most U.S. metropolitan areas (and
certainly for the cities of Chicago, Washington, D.C., San Francisco
and Los Angeles) will continue to grow -- probably at a rate of about 2
1
to 4 percent a year. -For example, data for Manhattan bridge and
tunnel crossings for New York City for the period 1963 through 1970 show
that passenger vehicle crossings increased at an annual average rate
2
of 2.7 percent.
In Los Angeles, data for the downtown area developed
from cordon counts indicate
that:
"There has been a trend of steadily
increasing cordon area vehicular travel since 1967, subsequent to the com-
p1etion of the Santa Monica Freeway route. last leg of the downtown loop.
3
in the early part of 1965."
A comparison of the number of passenger cars
1. In some of the large cities. growth into and out of the CBD may be
stabilized. but improvements in capacity resulting in lower travel times
or added capacity may be expected to generate added traffic. For example,
the additions to tunnel and bridge facilities in New York City appear to
be at capacity levels of operation within two years of their completion.
2. New York Environmental Protection Administration. "Proposed Plan for
Meeting Federal Air Quality Standards Relating to Carbon Monoxide. Hydro-
carbons. Nitrogen Oxides. and Oxidants in New York City." New York, 1972.
(Mimeographed draft.)
3. City of Los Angeles. Department of Traffic. Cordon Count:
Los Angeles 11av 1970. p. 24. (Mimeographed.)
Downtown
-------
3-22
inbound to the Los
Angeles downtown between 1967
1
of 3.7 percent per year.
and 1970 indicates an
annual growth rate
From a pollution viewpoint, both long-term traffic trends and in-
duced travel tend to ltmit the air pollution control potential of traffic
flow tmprovements in the medi.um- and long-term period.
In mos t metro-
politan areas, the additional capacity afforded by traffic flow tmprove-
ments would tend to be "used up" within two to four years because of the
higher volumes which would be attracted.
Travel induced by substantial
traffic flow improvements (i.e., far greater than the present levels of
highway and street tmprovement
programs) could contribute an additional
amount of growth in the downtown street network as latent-demand is
activated.
These higher growth rates, of course, could consume additional
capacity even more rapidly.
Impact of Traffic Improvements on Speed
Appraisal of the network impact of traffic flow improvements on speed
requires a data base presently not available.
To begin with, there is
no comparability for existing data, all of which relate
to specific
traffic flow techniques implemented in specific cities at specific sites.
The site specific nature of traffic flow improvements has already been
discussed.
Second, even if (judgmentally) comparable experience were
1. City of Los Angeles, Department of Traffic, Cordon Count:
Los Angeles May 1970, pp. 21, 35.
Downtown
Comparison of historical cordon count data indicates that initial
development of the regional freeway system consisted primarily of routes
adjoining the downtown area and extension of these radia] routes to the
outlying suburbs. The trend of decreasing l6-hour vehicular traffic
volumes crossing the cordon boundaries (starting after 1957 when historical
peaks were reached) was primarily the result of the diversion of non-down-
town oriented trips to the expanding freeway network.
-------
3-23
examined, the data typically available does not include observations over
a period long enough to enable evaluation of major repercussions; only
the most immediate ~pacts are usually measured.
Furthermore, traffic
flow ~provements at one point of the street network (e.g., at a specific
set of intersections) frequently result in deterioration in traffic con-
ditions at same point; typically, however, these network-wide trade-offs
are never considered.
Data from one recent study Which did consider
these trade-offs are summarized in Table 3-4.
Table 3-4
"BEFORE" AND "AFTER" SPEEDS FOR SIGNAL PROGRESSION
EXPERIMENTS IN NEWARK, NEW JERSEY
Experiment Peak Speed in MPH
Number Direction Period Before After change
1 8.9 14.3 +5.4
B100 North2 PM
South 1M 9.9 8.4 -1.5
B93 2 PM 15.7 13.6 -2.1
Northl
Sou th. PM 12.8 16.7 +3.9
Source: Highway Research Board, National Cooperative Highway Research
Program Report 113, Optimizing Flow on Existing Street Networks
(Washington, D. C.: National Academy of Sciences-National Academy of
Engineering, 1971).
1.
Predominant Direction of Flow.
2.
Minor Direction of Flow.
-------
3-24
Examination of Table 3-4 shows that for experiment number B100
northbound traffic speed increased by about 61 percent, while for south-
bound motorists speed fell by about 15 percent.
In this case, the fact
that the southbound direction was the minor direction of flow (i.e., the
lower volume of traffic) meant that time losses to southbound motorists
were offset by large gains to northbound drivers.
Trade-offs such as
these must be evaluated for the entire street network including facilities
on which no changes may be feasible.
Despite the difficulties of developing network "averages" of the
impact on speed from implementation of various traffic flow techniques,
an effort has been made for purposes of this study to evaluate the evidence
and estimate the relative orders of magnitude of speed impacts which might
be expected.
Recent comprehensive research carried out under sponsorship
of the National Cooperative Highway Research Program provided the major
f . f . 1
source 0 ~n ormat~on.
The project provided information based on actually
demonstrated methods of nnproving traffic flow on complex networks of city
streets as compared with the usual information available for only spot
. 2
or arterial ~mprovement.
Dozens of traffic engineering improvements were
implemented and evaluated in Newark, N.J. and Louisville, Kentucky.
A
1. Highway Research Board, National Cooperative Highway Research Program
Report 113, Optimizing Flow on Existing Street Networks (Washington, D.C.:
National Academy of Sciences-National Academy of Engineering, 1971), p. 3.
2. The project actually evaluated the means for better implementation
and application of operational control strategies, data collection, system
surveillance, etc.
-------
3,.25
network analysis was conducted to evaluate various models for use in the
analysis of downtown area traffic flows.
Work of the NCHRP study repre-
sents one of the most comprehensive efforts to evaluate the ~pact of
various traffic engineering techniques and provided the major source for
evaluating the magnitude of the impact of major traffic control improve-
1
ments on' speed.
Analysis of Recent Research
The exper~ents undertaken in Newark and Louisville were reviewed
and all observations in which there were positive increases in speed were
assembled.
Table 3-5 summarizes the result of that analysis.
Forty-three observations in which there were speed increases were
analyzed,
and the percentage change in speed for "Before" and "After"
conditions were calculated.
For the purposes of analysis, only those ob-
servations which resulted in favorable results (i.e., positive increases
2
in speed) were utilized.
Frequency distributions were prepared of the
percentage changes in speed and the actual "Before" and "After" speeds.
1. The only approach not evaluated in the NCHRP project was the use of
computer-controlled traffic and electronic guidance (which was considered
beyond the scope of their study). However, our own discussions with traffic
engineers and specialists in computerized control traffic indicate that any
additional improvement as a result of computerized control would fall within
the upper bounds of our estimates of speed changes in this chapter.
2. Traffic flow control experiments with negative speed results were not
taken into account. It was assumed that any speed losses which were not
offset by substantial gains in dominant traffic streamswou1d not be con-
tinued. In addition, our purpose was primarily to show the upper bounds
of emission reductions which would be possible with successful traffic con-
trol and flow techniques. The possibility that some "improvements" may
actually reduce speeds, however, should be kept clearly in mind.
-------
3-26
Table 3-5
(page 1 of 2)
SPEED CHANGES FROM TRAFFIC CONTROL EXPERIMENTS
IN LOUISVILLE, KENTUCKY, & NEWARK, NEw JERSEY
Experiment
Type Ł. Number
Direction
Time
Travel Speed (MPH)
Before After
Percent
Change
Ref.
Si~na1 Pro~ression: NB 1
B 100 - Newark PM 8.9 14.31 60.7 Tables 17
SB AM 12.3 18.2 48.0 Ł. 20, pp.
B 93 Newark NB 1 PM 7.4 16.4 121.6 66 & 69,
SE 2 PM 12.6 14.2 12.7 G-136,
SB 1 PM 12.8 16.7 30.5 p. 323
NB AM 12.7 14.5 14.2
SB 1 AM 13.1 15.3 16.8
B 88 Newark EB AM 11.0 15.9 44.5 Table G-ll1,
WB 1 PM 9.0 12.0 33.3 p. 299
EB AM 11.1 19.1 72.1 Table G-ll2,
EB PM 11.2 12.3 9.8 p. 300
WB PM 9.8 12.7 29.fi
One-Way Streets:
Speed Ł. Delay Analysis
E 30 - Louisville
Me11wood Ave. EB AM 16.6 20.2 21. 7 Table G-l,
EB PM 17.'3 20.6 19.1 p. 156
EB All 16.9 20.4 20.7
Story Ave. EB PM 18.1 20.6 13.8
EB All 19.5 20.4 4.6
WB AM 18.2 27.3 50.0
WB PM 21.2 26.9 26.9
WB All 19.7 27.1 37.6
All Directions All AM 17.2 23,8 38.4
Ł. Streets All PM 17.5 23.8 36.0
All All 17.4 23.8 36.8
Directional Control
Ł. Lane Use:
Speed Ł. Delay Runs
E 31 - Louisville NB AM 10.9 19.4 78.0 Table G-3,
NB PM 10.7 17.9 67.3 p.161
SB PM 15.3 16.8 9.8
All All 13.8 17.2 24.6 Table G-11,
p. 162
1. Predominant direction of flow
2. Minor direction of flow
-------
3-27
Table 3-5
(page 2 of 2)
Experiment Travel Speed (HPH) Percent
Type 6. Number Direction Time Before After Olange Ref.
Reversible Lanes: 8.2 1
B 78 - Newark SB AM 12.21 48.8 Table G-9,
p. 125, p.18,
Tables 22-3
Lane Ma rkinas :
B 86 - Newark EB AM 13.7 15.7 14'.6 Table G-14,
WB AM 17.6 18.8 6.8 p. 182
Left Turn 6. Pedestrian
Controls:
A 7 - Newark EB AM 6.5 10.9 67.7 Table G-32,
WB AM 9.9 12.0 21.2 p. 211
SB AM 12.8 14.3 11.7
WB PM 5.5 6.5 18.2 Table G-33,
p. 212
Truck Loading
Res trict i'Jns:
C 123 - Newark Segment 1 All 4.01 5.51 37.5 Table G-34,
p. 217
Channeliza tion:
A 33 - Newark WB AM 8.61 11.01 27.9 Table G-44,
p. 238
D 68 - Louisville Speed 6. Delay AM 24.51 25.01 2.0 Table G-74,
p.263
.Network Si2nal
Coordination:
E 35 Louisville EB AM 19.2 21.1 9.9 Table G-154,
WB AM 14.3 15.5 8.4 p. 346
Avge. AM 16.7 18.3 9.6 do.
EB PM 14.4 17.9 24.3 Table G-155,
Avge. PM 14.4 14.5 0.7 p. 346
Avge. AM ...1l.:.L ...il.&.. ---LL Table G-156,
p. 347
Average (Mean) 13.7 17.2 25.5
Source: Highway Research Board, Optimizina Flow on Existing Street Networks, National
Cooperative Highway Research Program Report 113 (Washington, D.C.: National Academy
of Sciences-National Academy of Engineering, 1971).
1. Estimated using calculated Delay Ratios and Delay Ratio-Travel Speed Curve.
-------
3-28
The frequency distributions were then plotted, as shown in Figures 3-3
and 3-4.
In terms of the percentage changes in speed resulting from these
experiments, Figure 3-3 shows that about 67 percent of the observations
fell within the class interval ranges of 5-10 percent and 35-40 percent.
Though the distribution of speed changes is statistically skewed, it
would appear from data in Figure 3-3 that the best range for expected
speed change from similar experiments (on a network basis) would be re-
presented by values between these two class intervals (which account for
almost 70 percent of the observations).
1
observations was 27.8 mph.
The arithmetic mean for 42 of the
The median percentage change was 28.5 percent.
Based on "Before" and "After" speeds, frequency distributions were
also prepared for the 43 experiments (Figure 3-4) and the median speed
for "Before" and "After" conditions calculated.
These calculations in-
dicate
that the median speed for "Before" conditions was 13.6 mph. and
for "After" conditions was 17.3 mph.
The increase from 13.6 to 17.3 mph.
represents a 27.2 percent increase and compared closely to the mean and
median percentage changes shown in Figure 3-3.
Calculation of the mean
"Before" and "After" speeds showed a very similar range of change of
25.6 percent (Figure 3-4).
1. Because it was an extreme value, the speed change of 121.6 percent was
dropped for calculation of the arithmetic mean. It is, however, shown in
Figure 3-3 in the class interval 80 and over. It was not excluded
for calculation of the median because it does not affect the median value
significantly.
-------
-------
5 Tar; kOOI$VTttŁ j KEK
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3-31
Application to Six Target Cities
It was recognized for the purpose of the present study, of
course, that the experience in Newark and Louisville would not be pre-
cisely comparable to data which might be developed for San Francisco,
Los Angeles, Chicago, Washington, D.C., New York and Denver.
However, the
traffic control techniques used in Newark and Louisville were comprehensive
and encompassed the most promising approaches presently available (short of
using computers to help implement these controls more efficiently).
Based
on this data, in conjunction with experience elsewhere and traffic engineer-
ing judgment, the upper and lower bounds of network impacts which might be
expected from implementation of traffic flow techniques was estimated.
Using the class interval range accounting for 67 percent of the observations
as the boundaries, a low, high and intermediate speed impact
developed (Table 3-6).
Thus, the mid-point of the lower and upper class
Table 3-6
RANGE OF EXPECTED CHANGES IN SPEED FROM
TRAFFIC FLOW IMPROVEMENTS
Percentage Change in Speed
Boundary Mid-point Rounded Value
Low 7.5 10
Intermediate 27.5 30
Maximum 37.5 40
-------
3-32
intervals were rounded to 10 and 40 percent, respectively.
'111e inter-
mediate value was based on the "Before" and "After" mean and median cal-
culations (Figure 3-4) rounded to 30 percent.
Maximum Feasible Emission Reduction
In considering the effect of these percentage changes on speed
(and therefore emissions), the most important consideration concerns the
initial baseline speed.
There are significant differences for both traffic
engineering and pollution control, depending on Whether baseline speeds are,
say, 10 mph or 25 mph.
For example, for pre-1968 vehicles, an increase
in speed from 10 to 15 mph will result in carbon monoxide emission re-
ductions on the order of about 29 percent, Whereas increases in speed
from 25 to 30 mph will result in emission reductions on the order of only
1
15 percent. Moreover, it must be remembered that speed Uffiprovements could
be short lived (about two to four years according to available evidence).
Finally, implementation of traffic flow techniques in the absence of other
controls may actually increase motor vehicle emissions (i.e., if average
vehicle speeds dropped to their former level but traffic volumes increased,
motor vehicle emissions would be worse).
1. These estimates are based on a preliminary EPA graph of carbon monoxide
~djus~en~ factor~ as a function. of. speed. See M. J. McGraw and R. L. Duprey,
Co~p~lat~on of A~r Pollutant Em~ss~on Factors" (prelUffiinary document, U.S.
Env~ronmenta1 Protection Agency. April 1971). The data used to derive this
graph were obtained from pre-controlled vehicles. See Appendix C for a
discussion of the speed-emission relationship.
-------
3-33
Institutional Feasibility
In many ways, most traffic flow techniques are relatively
1
easy to implement.
Most large cities are staffed (though not always
adequately) with competent traffic engineers, and have the administrative
capability to implement and enforce a traffic flow improvement program.
A great many cities also have prepared comprehensive traffic improvement
plans, for which only funding is now required.
Federal funding for such programs is currently possible through the
TOPICS (Traffic Operations Program to Increase Capacity and Safety) program.
The purpose of TOPICS is to assist urban areas in obtaining the maximum
efficiency and safety from existing urban streets through a systematic
application of traffic engineering techniques.
TOPICS improvements are
usually accomplished without right-of-way acquisition and do not normally
involve major construction efforts but rather the application of more
sophisticated signal control, parking restrictions, lane widening, turn
lane additions, channelization and other traffic engineering techniques.
Air pollution control, of course, is not one of the objectives of this
program, but it could occur as an important by-product of improved traffic
flow.
Major federal funds have been available for the TOPICS program only
since January 1969, and as of mid-197l, a total of $116,391,159 had been
approved to finance programs.
New and broader programs would require in-
creased funding.
Certainly, support from EPA for new programs would be
1. Probably the primary exception to this generalization concerns the
prohibition of on-street parking, a measure which is usually opposed by
local merchants and other area residents. This measure will be examined
in greater detail in Chapter 6, "Motor Vehicle Restraints."
-------
3-34
welcomed by the Department of Transportation, especially the Federal
Highway Administration which administers the TOPICS program.
However,
in view of our earlier discussion as to potential traffic growth and the
transient nature of these improvements, their intermediate and long-run
consequences should be very carefully considered.
The investment required for a major program of traffic flow
improvements (including freeway surveillance and computer control of
city street signal systems) would be very large.
Conversation with
State highway planners in Los Angeles indicated that there is a compre-
hensive plan for implementing "basic" improvements for traffic surveil-
lance and control with an estimated ten year cost of about $120 million,
or about $10 million a year.
Implementing network-wide traffic flow
control programs of the magnitude implied by this chapter's discussion
could require annual funding at least two to three times that level. 1
1. Even the research required for these programs is extremely expensive.
For example, in a recent appraisal of freeway control and ramp control,
research needs were estimated to be about $7 million for roughly a three
to five year program. See Highway Research Board, National Cooperative
Highway Research Program Report 84, Analysis and Projection of Research on
Traffic Surveillance, Communication, and Control (Washington, D. C.: National
Academy of Sciences-National Academy of Engineering, 1970). Table 1, p. 21.
-------
C HAP T E R
4
BYPASSING THRU TRAFFIC
Definition of Terms
In most urban areas there is a relatively large proportion of motor
vehicle traffic with no need to pass through the center of the city.
Two
components of this "thru traffic" can be identified: (1) inter-urban "thru"
traffic traveling long distances with no need to pass through any part of
the city. and (2) intra-urban "thru" traffic with origins and destinations
usually located on the periphery of the city (or at least not within the
I
heavily congested core).
Traditionally, traffic engineers have tried to separate thru vehicles
from traffic with origins and destinations within the core area of the city
in order to alleviate downtown traffic and transport problems.
To this end,
several measures are available to divert motorists who would otherwise pass
thru downtown areas.
In this chapter, we examine these measures (e.g., use
of circumferential routes such as beltways, directive signs and signals)
as well as some recently proposed possibilities
(e.g., physical barriers
in the central business districts combined with beltways) which have emerged
as a result of recent efforts to deal with air pollution.
Circumferential Routes-!Beltwaysl
One of the most widely used methods for bypassing thru traffic is
by use of graqe-separated controlled-access routes which circle the city.
1. Unless otherwise stated, we use "thru traffic" to refer to both travel
components. The distinction is important, depending upon whether the entire
metropolitan area, the central cities therein, or just the downtown districts
are under consideration.
-------
4-2
Often called "beltways," they are usually planned so as to be placed i.n
the first large band of uninhabited land just beyond the city limits or
built-up suburban residential areas.
Circumferential routes act both to
bypass traffic with inter-urban origins and destinations and to distribute
intra-urban traffic.1 Beltways, for e~cample, provide an almost ideal site
for the performance of truck-to-rai1 transfers, particularly at points of
intersection with rail facilities.
As a result of the interstate highway construction program, most
large cities now have some form of circumferential facility; many of these,
however, are not completed or fragmentary in nature.
In some cities (e.g.,
Los Angeles and New York), beltways do not take on a circular character,
whereas in others (e.g., Washington, D.C.) they literally circle the entire
2
central city.
l!!!!er Loo2,2
In addition to circumferential facilities located just beyond city
limits, some central cities are served by "inner loops" situated at the
outer edges of the downtown district or slightly beyond.
Such faci 1i ties
1. Particularly where no "inner loops" exist, beltways may serve primar-
ily to distribute traffic from the suburbs (i.e., intra-urban travel) along
major arterials leading downtown. This has been the case for the Washington,
D.C. beltway, somewhat to the surprise of transportation planners who ex-
trips by facilitating high speed north-south movement. See, National Capital
Region Transportation Planning Board, Impact of the Capital Beltway: Some
Notes and Observations, Information Report No. 13 (Washington, D.C.: Council
of Governments, November 1968). pp. 5ff.
2. Central cities, usually defined as those areas within the incorporated
limits of the major city in a given metropolitan area, are distinguished
from the central business district (CBD), which generally refers to the
high-density, commercinl and business cores of cities. Exact definitions
of central business districts vary, of course, with some jurisdictions
having more than one CBD.
-------
4-3
function primarily as distributors for traffic moving in and out of the
CBD.
Osaka, Japan, for example, has a loop which circles the edges of
the CBD, and permits traffic to move quickly around the CBD and avoid
congested city streets.
To the extent that traffic moves rapidly on an
inner loop, trips tend to be diverted away from city streets; crosstown
traffic using city streets (and their associated at-grade stop lights,
intersections, stop signs and delays) also tends to be be reduced.
Directive Signs and Signals
Especially where circumferential facilities are not available,
directive signs and/or signals are often used as a means of encouraging
traffic to bypass the CBD.
In many cities, bypasses are identified by
special signs as ~ecommended routes to be used to avoid congested areas.
Restrictions by weight and/or time of day may be placed on vehicle
movements along specific arteries, especially those expected to be congested
during peak hours.
For example, trucks may be prohibited on certain routes
passing thru the CBD by designating special truck routes, so as to either
divert heavy trucks to higher-load bearing roadways or to prevent their
mingling with passenger vehicles during the most congested period of the
day.
Special Stickers
Another means to divert thru traffic would be through use of special
stickers, which could be color-coded as to specific route and
perhaps
time of day.
Drivers without special stickers would be required to use
only bypass rdutes.
Thus, if a driver wished direct access to the CBD,
-------
4-4
,
the sticker would permit him to use appropriate arterialsl and connector
streets.
To the best of our knowledge, special stickers for the above
purpose have not been tried.
1
An additional possibility would be to use tolls.
Thru routes,
for instance, could be made toll-free in order to encourage their utiliza-
tion.
However, if such toll-free bypass segments are to significantly
attract thru traffic, the toll portions would have to have substantially
higher rates to begin with than is presently the case.
Bypass Combined with Motor Vehicle Restraints
As indicated in Chapter 6 ("Motor Vehicle Restraints"), a number
of measures could be applied to reduce motor vehicle use in central cities.
Combining these measures with bypass facilities could result in substantial
reductions in motor vehicle emissions.
An important example of this technique was implemented in Gothenburg,
Sweden in 19702.
The city's CBD was divided into wedge-shaped quadrants.
1. Among the large cities with toll facilities on major entry points of
high capacity highways leading into the city are Boston, New York, Phila-
delphia, Baltimore, Chicago, Kansas City, Jacksonville and Miami. However,
these facilities are universally used to raise revenues, not to control
motor vehicle traffic.
2. Traffic restrictions were initially instigated in Gothenburg at the
urging of various public officials concerned with the severe traffic con-
gestion developing during pre-Christmas shopping hours. The chief of the
fire brigade was concerned with difficulties in gaining access to CBD areas
for fire equipment. Officials involved with traffic accidents, public
transit, and air and noise pollution also supported traffic restrictions.
For further discussion of the planning and implementation of Gothenburg's
traffic restraint scheme, see Curt M. Elmberg, "The Gothenburg Traffic
Restraint Scheme" (Paris: Organization for Economic Cooperation and
Development, May 1971). (Mimeographed.)
-------
4-5
Physical barriers I were constructed between these quadrants, thus making
traffic through the CBD impossible (except to emergency vehicles such as
fire or ambulance and public transit which are permitted to pass.
In effect,
each quadrant became a self-contained precinct with only local circulation
allowed.
All other traffic was required to use a ring road (similar to the
inner loop facilities discussed above), entering and leaving each quadrant
at designated locations.
For a schematic representation of the Gothenburg
scheme, see Figure 4-1.
The success of the barriers in decreasing thru traffic in Gothenburg
can be clearly seen.
After eight weeks of operation, traffic on one of
"
the main arterials (Ostra Ramngatan) was decreased by some 70 percent.
As
Figure 4-1 shows, traffic has shifted to the peripheral streets.
Barriers have not been used in large scale anywhere in the United
States as yet.
The size of the experiment in Gothenburg (whose population
numbered slightly more than 444,000 in 1971) does not provide adequate
evidence that a similar strategy can be easily and quickly transferred to
any major United States city.
Particularly for the six cities under study
for this project, the size and extent of motor vehicle ownership make it
1. Physical barriers consisted of movable concrete "curbing" in sections
approximately one foot high and three feet wide. In some cases large
directional signs were mounted onto curb sections to indicate traffic
direction at critical points.
-------
4-6
Figure 4-1
SCHEMATIC REPRESENTATION OF" GOTHENBURG, SWEDEN TRAFFIC RESTRAINT SYSTEM
+1 .
+ 1 0/0
+10 %
Heden
-1-&';
Source: Curt~. Elmberg, "The Gothenburg Traffic Restraint Scheme"
(Paris: Organization for Economic Cooperation and Development, May 1971), p. 22.
Note: Hatched areas are quadrants; lines represent major arterials.
Numbers refer to percentage change in vehicle voluI:les along central
area routes two weeks and eight weeks (figures in boxes) following
introduction of scheme in August 18, 1970.
-------
4-7
doubtful that a similar experiment could be implemented before at least
two or three years of p1anning.1
Two observations appear warranted from the Gothenburg experiment.
First, it would seem unlikely that the use of barriers provides for any
major reductions in area-wide vehicle miles traveled.
However, the Gothenburg
approach does appear useful in providing for some redistribution of emissions
from downtown districts already saturated to peripheral areas with less
pollution.
To the extent that average vehicle speeds could be increased,
of course, motor vehicle emissions would also be reduced.
Second, the Gothenburg experiment seems to suggest the necessity of
a circumferential route (e.g., an inner loop) relatively close to the re-
stricted area.
Thus, in cities such as Washington, D.C. (where beltways
have been built just beyond city limits) the use of barriers on a broad
scale would appear to require construction of a circumferential facility
much closer to the CBD.
Within the short term (i.e., five years) imple-
mentation of a major effort is probably not feasible for any of the six
cities under study for this project.
However, smaller-scale use of motor
vehicle restraints and existing arterials to redistribute traffic away
from specific critical locations may be possible.
1. Even the comparatively small Gothenburg experiment entailed a planning
period of seven years. Once the plans were finalized, preparatory work
included reconstruction of certain intersections on peripheral routes to
accommodate increased traffic loads, relocation of tram stops, route signing,
street painting, the placement of physical barriers and informational ad-
vertising. See, Curt M. Elmberg, "The Gothenburg Traffic Restraint Scheme"
(Paris: Organization for Economic Cooperation and Development, May 1971).
(Mimeographed. )
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4-8
Air Pollution Control Potential
Data to determine the extent of thru traffic (as the term is used
1
here) are difficult to come by.
The extent of thru traffic will vary
from city to city, depending on the inclusiveness of the term (e.g., intra-
urban traffic, inter-urban traffic, vehicles not parking), the time perioJ
considered (e.g., peak or all day)
region,
ticular area.
and the area of study (e.g., metropolitan
the central city or CBD), as well as the travel patterns of the par-
Nevertheless, it appears from available data that in the central
cities of many American metropolitan areas, thru traffic can account for
a substantial share of total traffic volumes, even at peak hours:
1.
The Buffalo Board of Safety estimates that between
60 and 70 percent of all vehicles passing thru the
downtown area have neither origins or destinations
there.
2.
In the downtown Milwaukee plan, the authors state:
"Finally. the whole traffic problem in the central
business district is aggravated by a serious con-
flict between local and thru traffic. It is esti-
mated that around 70 percent of the vehicles enter-
ing the CBD have destinations there and the remain-
ing 30 percent are merely passing through."
3.
In New Orleans, it was determined that "the 71,891
vehicles passing thru the central business district
without parking comprised about 78 percent of the
in-bound traffic between 10:00 a.m. and 6:00 p.m.
on an average 1960 weekday,"
1, In some areas, different concepts (e.g., that of "external trips,"
because at least one end of the trip is outside the area of analysis)
are used by transportation planners. In virtually all cases, however,
data about travel are obtained by interviewing a sample of drivers cross-
ing a given cordon line, which could be drawn around the metropolitan
area, the central city or downtown districts. How each of these areas
is defined, in turn, can also vary from area to area.
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4-9
4.
In Atlanta, the daily number of persons passing
thru, as against those destined for the CBD were
found to be roughly equal in cordon counts performed
in 1941, 1945, and 1948; furthermore, a count in
1953 revealed that the number just passing thru had
risen to 57 percent of the total.
5.
In Detroit, 25 percent of the evening traffic of
about 73,000 person-trips consists of thru trips;
of the 18,200 thru trips, 6,800 are thru transit
trips.l As suggested by these data there appears
to be considerable variation in thru traffic from
city to city. 2
The above data, it should also be noted, are somewhat out of date,
and for medium-sized cities only.
More recent information for the CBD's
3
of large U.S. cities is difficult to come by but it appears that thru
traffic probably accounts for no more than a third of total traffic in
4
these areas.
If the central city as a whole is considered, the proportion
1. Based upon special CBD traffic study and cordon counts, cited in J. R.
Meyer, J. F. Kain, and M. Wohl, The Urban Transportation Problem (Cambridge,
Mass.: Harvard University Press, 1965) p. 87.
2. From an air pollution point of view it is particularly important to
distinguish between thru person-trips and thru motor vehicle trips. The
latter probably account for a disproportionately large share of vehicle
miles traveled, since thru trips tend to be longer than other categories.
3. In most cases, obtaining such data would require special surveys on a
city-by-city basis.
4. This proportion probably tends to increase in the medium-sized and
smaller cities, although much obviously depends upon the area's highway
and street system and location vis-a-vis major inter-state routes. Cities
located at major junctions along east-west and/or north-south routes (e.g.,
Chicago or Indianapolis) tend to have a higher proportion of thru traffic
than those situated at route terminations (e.g., coastal cities such as
San Francisco). ~,
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4-10
1
of bypassable traffic would be even less, about 5 to 20 percent of total
traffic approaching most medium-and large-sized cities according to one
. 2
est~mate.
From an air pollution control viewpoint, bypassing thru traffic
would (1) shift vehicle miles traveled away froQ already congested central
city roadways and (2) smooth traffic flows by a separation of thru and
local traffic in the areas affected.
Hence, the air pollution control
potential of bypassing thru traffic is multiple in effect; both of the
above results would reduce emissions downtown, the first by redistributing
vehicle miles traveled (and hence emissions) elsewhere, and the second
by bringing about higher average vehicle speeds and fewer stops and starts
and idling (and the emission reductions associated with these improvements).
Air pollution control potential of better bypass facilities alone,
however, is currently limited by a number of factors.
First, as noted above,
beltways (and in some cases inner loops) already serve most major U.S.
metropolitan areas.
In the short term there is little doubt that these
facilities do reduce congestion (and emissions) by diverting thru trips
and improving traffic flow.3 There is little reason, however, to think
1. How much less would depend upon the relative contribution of inter-
urban and intra-urbantraf.fic(thelatter consists of trips whose origins
or destinations are usually within city limits).
2. National Capital Region Transportation Planning Board, Current
on the Outer Beltway, Information Report No. 14 (Washington, D.C.:
of Governments, December 1968), p. 5
Planning
Counc il
3. In the medium and long term,
from the highway improvement and
generates.
however, more and longer trips may result
the dispersed residential development it
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4-11
that significantly more traffic could be attracted than is currently the
case, except by imposing motor vehicle restraints on the street system of
the city itself.
Second, most measures (again, excepting motor vehicle restraints)
designed to divert thru traffic depend upon the voluntary compliance of
drivers, and thus upon the relative attractiveness of traffic conditions
on bypass routes as compared to the city street system.
However, to the
extent that traffic grows to fill the capacity of circumferential routes
(as is commonly the case), conditions along these routes are no more
attractive than on city streets, drivers are not diverted, and even in
the short-term motor vehicle emissions are not appreciably reduced.
Again,
however, much depends upon the annual traffic growth in the area, especially,
as noted in the previous chapter, the extent to which the existing city
streets are "saturated" with traffic.
In the long-term, construction of
circumferential routes tends to encourage residential and commercial deve10p-
ment along the alignment and/or within easy access.
This, in turn, tends
to further population dispersion, increase average trip lengths, and result
1
in gr.eater motor vehicle use.
Use of directive signs and signals is also dependent upon the volun-
tary compliance of drivers, since, except for commercial traffic, bypass
routes marked by such signs and signals are optional in most areas of the
1. For example, since the Washington, D.C. beltway was completed in the
mid-1960's, auto commuting trips are up sharply, both in absolute numbers
and in proportion to total trips. And, ,"while commuting to the District
of Columbia is forecast to increase by 83 percent over 1960 levels by 1976,
circumferential travel increases of between 104 and 610 percent are expected."
National Capital Region T~ansportation Planning Board, "Travel Demand for
the Outer Beltway" (Washington, D. C.: Council of Governments (undated).
(Mimeographed.)
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4-12
United States.
For this reason, directive signs and signals are infre-
quent1y followed, particularly where vehicle operators are familiar with
the area.
Drivers unfamiliar with the area (i.e., most inter-urban thru
traffic) are more likely to use optional bypass routes, but the fact that
such routes are optional means they are unlikely to divert drivers, espe-
cia11y if the alternate routes are not grade-separated and/or controlled
access.
Significant diversion of thru traffic, therefore, will probably
require some form' of motor vehicle restraints (see Chapter 6) in the down-
town areas of the central city.
Maximum Feasible Emission Reduction
The two principal possibilities for bypassing thru traffic are the
use of circumferential routes (e.g., beltways) and directive signs or
signals.
1
To the extent that these measures depend upon new construction,
they cannot be implemented within the next five years.
To the extent that
other measures are available and designed specifically to attract and divert
thru vehicles, some limited reductions may occur.
Data are not available to permit exact estimates as to the emission
reduction potential of these measures.
However, in our best judgment the
reductions which could be achieved in the short-term from bypassing thru
traffic would be unlikely to exceed 5 percent in most central cities.
Greater reductions might be possible in some CBD's, particularly if measures
1. For some simple construction activities, some improvements might be
possible. For example, special ramps or very short segments of connecting
arterials to provide for bypass linkages could be built to provide for
some bypassing. These possibilities would have to be specifically identi-
fied for the purposes of study.
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4-13
to bypass traffic were combined with motor vehicle restraints (see Chapter 6).
Evaluation of the multiple effect of these measures (i.e., taking into account
increases in vehicle speed) is not possible without computer simulation,
which is beyond the scope of this project.
Institutional Feasibility
As noted in the discussion on traffic controls, construction of major
highway facilities including circumferential routes is not likely to be
feasible within the time limits of 1977.
In urban areas where circumferen-
tial facilities are already under construction, some bypassing of through
traffic might be possible by 1977, but where no plans exist, at least eight
to ten years would be required.
Even with an accelerated effort, it is
unlikely that major construction of circumferential facilities could be
achieved in less than five to eight years.
-------
CHAPTER
5
IMPROVEMENTS IN PUBLIC TRANSPORTATION
Definition of Terms
In the present chapter, we consider mass transit as conventionally
defined (rail and bus systems) as well as a number of other means of con-
veyance such as the taxi, demand responsive systems, car pools and people
movers.
Conceivably, improvements in public transportation could reduce
motor vehicle emissions in the short run, by attracting motorists away from
their automobiles, and in the long run by encouraging high density deve1op-
ment and more efficient land-use.
In the paragraphs which follow, we will review the opportunities
for public transport ~provements over the short (i.e., five-year) term.
In subsequent sections ("Air Pollution Control Potential" and "Maximum
Feasible Emission Reductions"), we examine the potential of these ~prove-
ments for reducing motor vehicle emissions.
The fin.al section ("Institu-
tional Feasibility"), considers the principal institutional problems as so-
ciated with implementing the most important candidates.
Before proceeding, however, a caveat is in order concerning the role
of public transport improvements in the context of air pollution control.
Extensive review of all recent evidence leads us to conclude that public
transport ~provements alone hold out little promise for major modal diver-
sions, much less for reductions in motor vehicle emissions.
Public trans-
port improvements, in other words, are a necessary but not sufficient condi-
tion for reducing motor vehicle emissions.
Reducing emissions would require
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5-2
other measures (e.g., parking controls, auto free zonesl) to restrict or
restrain motor vehicle use.
But for these measures to be feasible, public
transport must be improved.
Consequently (and although it is treated
independently in this chapter), public transport for purposes of air
pollution control should be considered only as complementary to a larger con-
trol strategy (i.e., one consisting of motor vehicle restraints and other
measures discussed in this report).
Public transport must playa useful
role, although it cannot by itself be relied upon to reduce emissions.
Rapid Transit Systems
By rapid transit systems we refer to grade-separated rapid rail
systems (other than busways) which are particularly suited for line-haul
2
high density corridors in heavily populated areas.
Passenger capacities
of these systems range from 30,000 to 60,000 persons per hour for each
track.
Traditionally, grade-separated rapid rail transit has involved
higher initial capital construction cost than highways.
In urban areas,
1. See Chapter 6, "Motor Vehicle Restraints." Without these measures,
public transport improvements (particularly rapid rail) may cause motor
vehicle emissions to increase over the long-run where they are currently
worse (i. e., in the downtown or other densely developed districts).
2. Only five metropolitan areas in the United States presently have rapid
rail systems: New York, Chicago, Boston, Philadelphia, and Cleveland.
Two other areas (San Francisco and Washington, D. C.) have rapid rail
systems under construction. Pittsburgh, Baltimore, Buffalo, Atlanta, St.
Louis, Minneapolis-St. Paul, Miami, Detroit, Dallas, Denver and Honolulu
are presently in various stages of planning rail systems. Even Los Angeles,
probably the example par excellence of an auto dominant city, is currently
considering a proposal by the Southern California Rapid Transit District to
construct a $420 million subway-elevated line to run 14 miles from the city's
downtown into Watts.
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5-3
however, the construction cost differentials between road and rail systems
d. . 1
seem to be 1sappear1ng.
Construction of new systems.
Historically, the gestation periods
for new rail systems have been very long in the United States.
Corridor
studies, pre-feasibility studies, feasibility studies and final designs
must all be undertaken.
Months or even years may be necessary merely to
acquire rights-of-way because of legal, technical and political difficulties.
Even after land is acquired, delays may arise due to difficulties in obtain-
ing financing and political acceptance and the time-consuming construction
of facilities.
In San Francisco, for example, preliminary studies for the
Bay Area Rapid Transit System (BART) date back to at least the mid-1950's
and a minimum construction period of ten years is anticipated.
Similarly,
the first study for the Washington, D~C.,Metro was begun in 1955 and com-
pleted in 1958.
Ground was not turned for construction until late 1969,
and the entire network (some 90 plus miles) will not be completed until
at least the end of this decade.
Given these long gestation times, ten years would seem optimistic
for opening even the first short stretches of line.
Certainly, no rapid
rail system which is not currently under construction or in the final
1. In urban areas of the United States (where right-of-way acquisition
is most expensive), the cost of constructing urban highways ranges
from $10 to $40 million per mile (for depressed freeways and complex
interchanges these costs are higher), while for rail, the estimated per
mile construction costs for San Francisco's BART and Washington, D.C.'s
Metro are $17.5 and $30.4 million, respectively. Costs, of course, vary
somewhat fr~m city to city depending upon local wage rates, soil conditions
and climate, and the penchant of City Fathers for elaborate construction
and rich furnishings.
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5-4
design stages of engineering, could be expected to be open for its first
service within five years.
Among the six metropolitan areas examined in
this study, only San Francisco's BART and Washington's Metro could be
open for service within the next five years. 1
Over an eight- to ten-year period (i.e., beyond the time frame of
this study), ~t may be reasonable to expect improvements in the construc-
tion techniques for tunnels and underground stations (e.g., better boring
equipment, improved techniques for excavating earth and rock, increased
use of prefabricated ~labs, and so forth).
If these or other improvements
materialize, reductions in construction costs may be expected, which in
turn could alter the relative attractiveness of tunneling rail transit
systems through densely developed areas.
These improvements might help
compress total implementation time somewhat.
However, since most
of the delays are not technologically related, about eight years from
initiation of the first study to opening of a first stretch of line seems
to be about the best that can be hoped for under present conditions in any
major metropolitan area.
Extensions of existing systems.
Construction of extensions to
existing rail transit systems appears somewhat more promising in the short-
term, and could conceivably be carried out within four to six years, assuming
1. Of those areas not considered for this study, Pittsburgh is pro-
bably the only major metropolitan area in the United States which has
final designs nearly ready. (The Pittsburgh system is to utilize the West-
inghouse Skybus, a train-like system that runs on rubber tires in a con-
crete guideway. An experimental version of the system has been operating
in a Pittsburgh park since 1966.) A five-year time frame (i.e., by 1977)
would similarly rule out contemplated rail systems in Atlanta, Baltimore
and Buffalo.
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5-5
1
a definite decision to proceed were taken now.
In addition to improved
construction techniques, the speed with which such extensions can be ini-
tiated and completed depends upon a number of factors.
These include the
amount of planning and financial programming already completed, the ex-
tent to which final designs have been finished, the degree to which system
specifications differ from those already in use and the amount of other
rapid Fail construction actually in progress in the area.2
Operational and service improvements.
In addition to construction
of'new rail lines or extensions to existing systems, rail transit rider-
ship could be increased by measures such as the following:
1.
Reducing fares -- fare reductions to at least 25t in a
base zone would probably do more than any other measure
to increase rapid transit ridership. Only Boston has
such fares at present. In all cases, fare reductions
would require extensive, continuing subsidies to cover
operating deficits. Commuter rail service would be a
parallel case.
2.
Increasing comfort, cleanliness and safety -- cleaning
up stations, better lighting and more active policing
would help (especially in cities such as New York and
Chicago). However, most of these measures would cost
far in excess of the additional patronage they would
generate (e.g., reducing noise in the older rail
systems and rehabilitating equipment would involve
1. Among cities currently working on extensions or major improvements to
existing systems are New York City, where, in spite of the rejection at
the polls last November (1971) of a $2.5 billion transportation bond issue,
officials say there is still enough money left from the 1967 bond issue
to start work on a new Second Avenue subway, and to continue links be-
tween Queens and several existing lines in midtown Manhattan; Phila-
delphia, where plans are set for expansion of the successful Lindenwold
line from New Jersey; Boston, where a $124 million bond issue was autho-
rized for improvements to the local system; and Chicago, which has re-
quested $500 million from the Urban Mass Transportation Administration
for two new subway lines.
2. With other rapid rail construction going on in an area, knowledgeable
contractors would be available with an incentive to negotiate quickly
for additional work.
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5-6
hundreds of millions of dollars in crack renovation and
car rebuilding for relatively modest increases in
ridership) .
3.
Increasing service frequency -- this improvement is
usually not important to rapid rail systems at peak
hours, although some frequency increases during off-
peak periods and on holidays and weekends could draw
more ridership.l
4.
Providing ParkIn Ride -- free or low cost parking
facilities at rapid rail stations could be an im-
portant factor in increasing patronage, particular-
ly for commuter rail services.
5.
Improving fare collection -- automation can speed
passengers on their trips and make possible more
flexible charges. Provision of monthly passes is
another example, and has proven a popular convenience
which can increase ridership on commuter lines.
Experimentation with extending and improving rail
servic e,
particu-
larly suburban commuter rail lines, has achieved success
in some
. 2
instances.
However, in virtually all cases where improvements have been
1. Any additional off-peak ridership, however, would probably not be drawn
from motorists, who generally (except perhaps in New York) have little or
no problem in moving about in their motor vehicles except at peak hours.
2. Federal assistance for experimentation with improvements in urban mass
transportation first became explicit in the Housing Act of 1961 and with
the expansion of that program in the Urban Mass Transportation Act of 1964.
Under this legislation and subsequent amendments, the Federal government
continued its commitment and financial support for research and development
of public transport improvements.
The transportation demonstrations that followed were primarily for
rail and bus systems and covered a broad range of operational improvements
designed to attract ridership. Experimentation was made with schedule changes,
fare decreases and increases, fare collection methods, improved speed of
headways, new equipment, and new systems or special services. In early
stages of the demonstration program, a major effort was directed at improv-
ing commuter services for the journey-to-work. Congestion (most critical
in the heavy traffic streams of peak hour work-oriented travel), not air
pollution, was the impetus for this effort. As indicated in an IPA study
of the first generation of these transportation demonstrations, some mea-
sure of modal diversion (i.e., motorists attracted away from their automobiles)
was accomplished and a number of definite marketiQg lessons were learned.
See Ralph E. Rechel and Lee H. Rogers, Review and Analysis of Reports of
Mass Transportation Demonstration Projects (Washington, D. C.: Institute
of Public Administration, 1967).
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5-7
implemented it is apparent that no single improvement -- reduced fareR,
increased service frequency, or provision of parkin ride -- has been res-
ponsible in and of itself for any major increase in rail transit rider-
ship.
Probably the most successful combination of improvements in recent
years has been the new Lindenwold line between southeastern New Jersey and
Philadelphia.
As detailed in Appendix E, riders were attracted to the
Lindenwold line by a package of improvements -- free and available park-
ing, travel time differentials, fast, reliable and comfortable service --
as well as disincentives to use the motor vehicle in terms of increased
congestion and increased bridge tolls along the paralleling highways,
Bus Systems
Since streets and highways constitute the most pervasive transpor-
tation network in this country, and since rapid rail systems are available
in relatively few U.S. cities, mass transit for most Americans means bus
service. Of total passengers carried by transit services in the United
1
States in 1970, almost 70 percent were carried by bus.
Bus systems present a promising area for improvement because they
can go anywhere on present rights-of-way.
This ubiquity is important be-
cause buses afford the potential for door-to-door (or nearly so) service,
and because buses can avoid the costly and time-consuming acquisition and
construction of their own rights-of-way.
The former is essential if sig-
nificant patronage is to be attracted in the future; the latter is necessary
1. American Transit Association, 1970-71 Tran~it Fact Book (Washington, D.C.:
1971), p. 3.
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5-8
if improvements are to involve relatively low initial investments and to
be implemented in the short term.
Scheduling usually stresses provision of bus for work trips, with
express services provided in some cases.
In most central cities, flat
fares are used, and where suburban services exist a zone fare is provided.
Equipment now in use in the United States is essentially homogeneous, the
only real difference being whether air conditioning is used.
Almost a11
bus services operate on roadways shared with automobiles; as a consequence,
they are frequently caught in the same traffic jams.
Existing bus service may be enhanced by (1) exclusive bus lanes,
(2) bus priority systems, and (3) a variety of operational and service im-
provements.
Exclusive bus lanes.
One approach to alleviating bus delays would
be to provide buses with their own reserved lanes, either physically sepa-
rate from freeway traffic (e.g., the so-called busway) or on special "bus
. 1
only" lanes on c~ty streets.
Technologically, exclusive bus lanes are
entirely feasible, although they have been infrequently tested.
Approximately
1. Rights-of-way for exclusive bus lanes may be secured in a number of
ways such as: construction of a new grade-separated roadway, including
those in the medians of existing divided highways; dedication of bus
only lanes in existing expressways or streets in the dominant traffic
direction; dedication to buses only of lanes from the opposite direction
of lightly used roadways during peak hours (i.e., by lane reversal).
Conversion of existing railroad rights-of-way to bus use has been active-
ly planned in Atlanta (since reversed) and Pittsburgh. This approach could
obviously be used in Washington, D.C., and several other of the metropolitan
areas considered for the study.
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5-9
five exclusive bus lanes are presently tn operation, and at least four are
1
in the planning stages.
An obvious problem with exclusive bus lanes is the difficulty of
fitting new rights-of-way into existing urban street and highway systems.
Less evident is the paradox that establishing exclusive bus lanes may well
increase congestion (and concomitant emissions) by increasing overall
delays.
Except in very few cities -- New York being one example -- buses
do not run often enough to use up the roadway capacity assigned to them
on an exclusive bus lane basis.
Hence, from a transportation point of
view, if one lane of a four lane highway is given over entirely to buses,
the time saved by bus riders will never quite compensate for the time lost
by motorists in the remaining three lanes.2
1. Exclusive bus lanes exist for the Washington, D.C. area, where a busway
of about 12 miles along 1-95 in northern Virginia (the Shirley Highway) is
the first such project which has been federally assisted; the New York City
area, where express bus lanes between New Jersey and Manhattan (the Lincoln
Tunnel) have been operating since the late 1960's, and where a lane reserved
for buses between Long Island and Manhattan (the Queens Midtown Tunnel) has
been in operation since 1971; Seattle, where eight feeder routes of the "Blue
Streak" express bus service all use an eight-mile segment of reversible lanes
on the 1-5 Seattle freeway; San Francisco, where the Oakland Bay Bridge has
an exclusive lane for ~uses of the Alameda-Contra Costa transit district;
and Boston, where an eight-mile exclusive bus lane on the southeast freeway
(from Quincy to Boston) is presently operating on an experimental basis.
Busways are planned for L08 Angeles (between El Monte and L.A.); Pittsburgh
(to feed into the CBD); Milwaukee (extending west from the CBD); and San
Francisco (along U.S. route 101 in Marin County and across the Golden Gate
Bridge).
2. See Highway Research Board, Mationa1 Cooperative Highway Research Program
Report 84, Analysis and Projection of Research on Traffic Surveillance, Com-
municatio~and Control (Washington, D. C.: National Academy of Sciences-
National Academy of Engineering, 1970). One way out of this problem would be
to allow some motorists (e.g., car poolers) on to the lane, but not enough to
clog its capacity (at which point even minor perturbations in the traffic stream
may cause slowdowns or stoppages). The idea has never been tested but is in the
planning stage in several cities.
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Bus Priority Systems.
Priority systems can improve bus flow on
freeways
(e.g., through use of exclusive bus ramps and lanes, and the
metering of automobiles) and on city streets (e.g., with bus-activated
traffic signals).
Metering motor vehicles on to freeways involves controlling the flow
at a rate which maintains traffic speeds at some defined level below the
point of congestion.l
Under a freeway system for buses, buses would not
be "metered on" as would other vehicles, but would enter the freeway "at
will," perhaps on their own bypass lanes as is now done in New York City at
the Lincoln Tunnel.
Priority access, of course, could be combined with
priority lanes on freeways (see "Exclusive Bus Lanes" above).
Since most buses travel over city streets, street priority systems
are especially significant.
Most traffic control systems today are de-
signed to move vehicles, without respect to differences in vehicle size
and/or carrying capacity.
Street priority systems for buses could be pro-
grammed to accord priority to people -- not vehicles --
so that the passenger
carrying capacity of the street system would be improved.
Operationally,
these measures entail programming traffic lights so as to accord priority
to loaded buses (e.g., by prolonging green signals for their utilization).2
1. Traffic flow techniques for city streets and urban arterials are dis-
cussed in Chapter 3 and Appendix D.
2. Sensing the approach of buses in traffic may be done in several ways.
One system already on the market uses a rapidly pulsing optical beam to
transmit signals from an approaching bus to an electric phase selector
which controls the traffic light.
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Extensive use of street priority systems can have important effects
in reducing bus delays.
For example, a study conducted in Delft, Netherlands,
calculated that the effect of influencing a series of ten traffic lights
could reduce bus delay times from 191 seconds to 37 seconds. 1
In addition,
schedule reliability could be substantially increased.
In general, the technology for street priority systems is relatively
simple and the price tag for most large cities is probably in the range of
about $2 million, a sum which represents an add-on cost to an existing pro-
gram
for traffic signals which would be required to move all vehicular
traffic, including buses. (Under this approach all vehicles must move smooth-
ly; otherwise the buses which are generally mixed in the traffic stream will
be slowed down as well.)
Street priority systems may also be usefully
2
combined with express bus service and other bus improvements, particular-
ly for line-haul journey-to-work trips.
Operational and service improvements.
Bus services in most cities
could be greatly improved (and ridership increased) by any of the following
operational or service improvements:
1. Organization for Economic Co-operation and Development, Consultative
Group on Transportation Research, "Improvements and Innovations in Urban
Bus Systems." Proceedin~s of the First Technolo~y Assessment Review
(Paris: OECD, October 1969).
2. Automatic vehicle monitoring (AVM) could be used to improve bus ser-
vices, either in combination with a street priority system, or independent-
ly. In and of itself, AVM information would enable better control of exist-
ing bus operations, adherence to schedules and greater economy in the use
of buses. Aided by a computer, AVM information on loading conditions and
passenger counts could hold out the promise of dynamic re-routing and re-
scheduling of buses to adjust routes and schedules to changes in demand or
traffic conditions.
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1.
Additional express service, especially provision of
express service for longer distances than presently
available, perhaps with longer runs on freeways and
expressways. Improved and more flexible design of
pick-up and delivery routes could also help.
2.
Increased frequency of schedules to help reduce door-
to-door travel times. Deterioration of transi~ ser-
vice in recent years has driven away many riders be-
cause of the long headways (i.e., the time between
buses).
3.
Reduction of fares, especially in base fares to 25t
or less. However, this is only of moderate importance
because demonstration projects have shown people will
pay high fares, including an increase, for notable im-
provements in quality and convenience of service.
4.
Improvements in schedule reliability. This could be
developed through use of vehicle locator systems. Un-
reliability of service is a valid basis for rejecting
much of the present transit system service.
5.
Facilitation of inter-modal transfers through use of
shelters, posting of connecting schedules and reliable
schedule adherence. Multiple mode trips (or even
multiple line trips) are at present disagreeably long,
unreliable and exposed to the weather in most areas.
In addition to the above
operational and service improvements, rider-
ship might be increased over the long term by improving the quality of
equipment.
In the short term, new bus designs are probably not possible,
but a reduction in the average vehicle fleet age to about five to seven
I
bus use.
years, and the universal use of air conditioning would help encourage
1. In the medium term buses could
less noise, smoother acceleration,
much easier steps to climb or none
be designed for fewer emissions and
better ingress and egress, and either
at all.
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Taxi Systems
Taxis are a common sight on American streets, although the taxi-
cab mode is seldom considered under the category of public transportation.
Traditional taxi service differs from rail and bus systems in that (1) it
does not provide a "mass" service (except for the occasional shared rides
permitted in some cities); and (2) it operates with completely flexible
routing (except perhaps for the occasional jitney service along fixed or
~emi-fixed routes). Because of its special characteristics, the taxicab
1
has seldom been included in studies of public transportation.
1. This omission can hardly be justified, however, in view of the fact
that the taxicab mode accounts for a significant portion of all public
transportation trips in some metropolitan areas. In the New York City
region, for example, nearly 1 million person-trips are made in taxicab~
on an average weekday, as compared to 4.5 person-trips made in the subway.
See, Tri-State Transportation Commission, Who Rides Taxis1 Regional
Profile, Vol. I, 1969.
In Washington, D. C. approximately 99,000 person-trips are made
in taxis on an average weekday, while bus service -- currently the only
other public mode -- provides about 336,000 person-trips within the same
period. From survey data as cited in Ho-Kwan Wong, "Some Demand Models
for the Taxicab System in the Washington, D.C. Area," (unpublished working
paper, Washington, D.C.: The Urban Institute, 1971).
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5-14
In addition to traditional taxi operations, the taxicab mode may
be said to encompass a variety of other taxi or taxi-like services, as
summarized in Table 5-1.
Table 5-1
VARIETIES OF TAXI SERVICE
Service
Description
Experience
Jitney Service
Usually larger vehicle
(12-15 passengers) than
standard taxi, serving
many origins to many des-
tinations, on fixed or
semi-fixed routes in
center cities and adja-
cent to main transit
routes or terminals.
Shared ride. Usually
not permitted by exis-
ting franchise systems.
Shared Taxi Service
Group riding. Occupied
taxis may be flagged
down on street. Many
origins to many desti-
nations service.
Taxi Car-Pooling
pre-arranged car-pooling
by taxi by suburban
commuters to CBD.
Jitney service along
Mission Street in San
Francisco. Pittsburgh
has an extra-legal system
and there are undoubted-
ly others in the United
States. In foreign coun-
tries, jitneys are quite
evident and carry large
proportions of total daily
passengers in many cities.
Required by legis-
lation in Washington,
D. C.
Appears to be fairly
widespread phenomenon
in Washington, D. C.
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5-15
Like buses, the taxicab mode is attractive for its ubiquity; it
can go anywhere on the existing street system.
Unlike buses, however, the
taxicab mode can be used to service the lower density districts in many
metropolitan areas where travel demand is so small and trip patterns so
dispersed that it is not economically feasible to route and schedule tran-
sit buses.
Taxis are suited to handle these low volumes of demand.
Par-
ticular1y if the taxi mode were developed into a demand-responsive system
(see below) substantially more off-peak business could be attracted than
is possible for conventional transit, thus reducing dependence on motor
vehicles (particularly the second car).
Improvements in the taxicab mode
(short of the demand-responsive systems discussed below) can be made in
two areas: (1) taxi dispatching and (2) existing taxi regulations.
Improvements in taxi dispatching.
Today's dispatching for the
taxi mode encounters three distinct but related problems.
First, dis-
patching is hindered severely by driver recalcitrance (e.g., the refusal
of drivers to indicate their whereabouts and availability).
Second, even
with better driver compliance, present-day dispatching would be time-con-
. d. ff' . t 1
sum1ng an 1ne 1C1en.
Third, with today's methods, the coordination of
1. Typically, dispatchers spend much of their time searching for available
vehicles in the vicinity of calls for service. For example, a dispatcher
may begin by asking if an empty cab is at the nearest taxi stand. If not,
he will ask if someone is cruising in the vicinity or is at a nearby stand.
If he gets several responses, a discussion may be necessary to determine
priority. If he gets none, he may suspend the search for several minutes,
then try again. In rush periods it may be a long while before he tries
again, even longer before he succeeds.
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5-16
large-scale taxi fleets is cumbersome.l
Either individually or in combina-
tion, these problems tend to produce long delays in responding to telephone
requests for service (and probably, less taxicab ridership as a result).
A computer-aided dispatching system2 would open the possibility of
dramatic improvements by enabling dispatchers to monitor large numbers of
vehicles and assign each service call to the nearest available vehicle. The
same system could also be used to assure driver adherence to planned policies
(e.g., guaranteed pick-up and delivery and maximum waiting and travel time)
and to check driver reports on the number and distance of trips served.
Use of the computer could also improve taxi service by large fleets (man-
agement and regulatory policies permitting) by combining all taxis in a
metropolitan area into a single fleet for dispatching purposes.
At the present time, computer-aided dispatching is still in the ex-
perimenta1 stage.
The pioneer in this field, Yellow Cab Company of Los
Angeles, is currently field testing a computerized dispatch system for
its fleet of approximately 700 vehicles.
Depending upon the outcome of
these tests, use of computerized dispatch may spread to other metropo1i-
tan areas, although the applicability of this system (as well as its cost
and effectiveness) in other less spread-out areas may have to be demonstrated.
1. Using present methods, a good dispatcher can handle perhaps 150 requests
per hour. However, it is difficult for several dispatchers sitting in a
room to coordinate their efforts for large numbers of vehicles, although
some crude techniques for doing so exist. Hence, the capability of each
dispatcher limits the economies of scale which might be realized through
dispatching.
2. Such a system could be informed by automatic vehicle monitoring (AVM)
data on the location and status of cabs, along with service requests and
their time of arrival; or such information could be provided by conventional
radio communication.
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Revising taxi regulations.
Regulations concerning taxi operations
exist in all U.S. cities and have an important bearing on the quality and
quantity of service offered.
A common regulation is to restrict entry into the market.
Entry
restrictions can be accomplished by placing a limitation on the actual
number of cabs permitted to operate within a city (e.g., New York where the
number of medallions is limited to almost 12,000); or by establishing a per
capita cab ratio (e.g., Miami which specifies one cab per 1500 population);
or by granting one or more exclusive franchises.
Such franchises may be
geographically exclusive (e.g., Los Angeles has six cab companies
for six zones) or may be limited to one or two exclusive franchises for
an entire city. 1
Another oft-encountered regulation is the officially
set fare.
The officially set fare is especially onerous2 when it fails to
allow rates to rise in rush hours when taxi costs can increase because of
street congestion.
Both restraints have tended to keep taxi fares higher and utiliza-
tion rates lower than they might otherwise be.
In Washington, D.C. (with
no serious entry restrictions) the fact that taxis are greater in number,
more extensively used, and at lower fares, suggests what could result from
less rigid regulations.
(At peak hours, similar limitations on entry
into specialized bus and jitney services may be quantitatively much more
important.)
Eliminating existing entry restrictions, however, would pose
a number of institutional problems (see below "Institutional Feasibility").
1. General Research Corp., "Characteristics of Taxicab Supply and Demand
in Selected Metropolitan Areas, II internal memorandum (Santa Barbara, Calif.:
General Research Corp., 1967).
2. Onerous on the drivers to be sure, but also on the public, which finds
cabs in operation at peak hours when they are most needed.
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5-18
Demand-Responsive Systems
Demand-responsive systems have been developed under a variety of
names including Dial-A-Bus,l Demand Actuated Road Transit (DART)2 and
3
others.
Perhaps the most descriptive designation is taxi-bus since the
system combines some features of both a taxi (door-to-door service) and a
bus (sharing rides and reduced fares).
Demand-responsive systems can be designed to operate with or without
fi~ed schedules or routes, picking up passengers at or near their doors on
a real-time (i.e., demand-responsive) basis and delivering them within
proximity of their destinations.
With riders sharing the vehicle, fares
might be reduced by as much as one-half from existing levels, thereby
tapping a substantial new market.
At the present time, some small-scale manually dispatched demand-
responsive services are appearing in inner cities, where low income resi-
dents, many without automobiles4 are entirely dependent upon existing
1. See, for example, Massachusetts Institute of Technology, "Dial-A-Bus"
(paper presented by Alan Altshuler and Daniel Roos at the Fifth Meeting,
Consultative Group on Transportation Research, Organization for Economic
Co-Operation and Development, Directorate of the Environment, Paris,
October 1970).
2. Institute of Public Administration and Teknekron, Inc.; Demand-Actuated
Road Transit (DART), Performance and Demand Estimation Analysis. Report to
the U.S. Department of Transportation (Washington, D.C.: Institute of
Public Administration and Teknekron, Inc., March 15, 1969).
3. Demand-responsive systems may operate with or without computerized
dispatch, although it is usually assumed that for large-scale fleets a
computer, complete with scheduling algorithm and probably an automatic
vehicle monitoring system would be required.
4. As of 1970, 50 percent of all
$3,000 did not own an automobile.
1971 Automobile Facts and Figures
turers Association, 1971).
family units with an annual income below
Automobile Manufactur~rs Association,
(Detroit, Mich.: Automobile Manufac-
-------
5-19
transit (mostly bus) for mobility.
In these areas, demand-responsive
systems using vans are increasingly being used to transport the elderly,
the handicapped, and job trainees to destinations they cannot easily achieve
through traditional transit services.
Usually, these operations involve
scheduling by a dispatcher who receives requests for transportation at least
a day in advance.
By approximating the comfort and convenience of an automobile (at
fares significantly less than for taxis),demand-responsive systems are pro-
bab1y the only public transportation mode potentially capable
1
successfully with the private automobile.
of competing
However, absent a large-scale
demonstration of demand-responsive systems (see below "Institutional Feasi-
bi1ity"), little more can be said about the kind of service which would be
required to attract substantial ridership.
Car Pools
Car pooling may be defined as the shared use of private passenger
cars,
2
especially for the journey-to-work.
Encouragement of car pooling
may take the form of tax relief or rebates, eligibility to use otherwise
restricted lanes (e.g., busways) preferences or reduced prices for parking
1. This would appear particularly true for the unstructured travel patterns
(i.e., dispersed origins and destinations) characteristic of low-density
cities such as Los Angeles and Denver.
2. Car pooling is considered in connection with the journey-to-work be-
cause (1) only work trips are sufficiently regular (in terms of departure
and arrival t~es and origin and destination patterns) to permit pooling,
and (2) because work trips tend to have average occupancy rates well below
trips for other purposes, and hence offer the greatest potential for sharing
of vehicles.
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5-20
and/or bridge and tunnel tolls and improved information (e.g.,
a com-
puterized car pool information service to facilitate formation of car
1
pools) .
Aside from such "official" encouragement, there may be other exist-
ing incentives and disincentives to form car pools.
For example, car owner-
ship, operating, toll and parking costs can be cut substantially with car
pooling to the point that, short of walking, no other mode of transportation
is cost competitive.
Conceptually, car pools appear to have enormouS potential for alle-
viating traffic congestion (and concomitant motor vehicle emissions) at peak
hours.
Average vehicle occupancy rates vary somewhat from city to city,
depending as well on trip purpose, time of day, and place of use.
But
generally, these figures appear to be about 1.5 (driver plus an average of
0.5 riders) for the downtown areas of most American cities at peak hours.2
Assuming other things equal, simple arithmetic shows that by increasing
3
this figure to 2.0, a 25 percent reduction in traffic could be achieved.
At the same time, however, the almost uniformly low occupancy rates
1. These incentives, of course, could be combined with measures (such as
the motor vehicle restraints discussed in Chapter 6) specifically designed
to discourage use of motor vehicles with low occupancy rates.' F(i)r present.,
purposes, however, we confine the discussion of car pools in and of them-
selves without reference to motor vehicle restraints.
2. At the low end of the range is Los Angeles with a 1. 06 average vehicle
occupancy for the journey-to-work. Source: Los Angeles Transportation
Study, Origin and Destination Survey, 1967.
3. Other things are not equal, however, as explained below, "Air Pollu-
tion Control Potential."
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5-21
for most U.S. metropolitan areas attest to the fact that car pooling in
large numbers is seldom found.
The reason is simply that car pooling is
highly restrictive in terms of service offering;
Generally. car poolers are heavily constrained with res-
pect to both the times and destinations served by the
car pool. Car poolers need to work and live in close
proximity, and to have common working hours. In a cer-
tain sense, the level of service afforded by car pooling
is poorer for most than that available for transit, un-
less, of course, poolers can find similarly minded tray-
elers with common work hours, home and work locations.
In addition, of course, there is the common problem of many car pools --
the member who happens to be late either morning or evening or both.
Given these constraints, the feasibility of car pooling can be
expected to vary from city to city, depending upon the degree to which
employment centers are concentrated, work hours are standardized, and
communication is facilitated among employees within and among different
firms. 2
Except where employment is concentrated in a small number of govern-
ment agencies or firms, communication among potential car poolers is almost
1. Martin Wohl, ''Must Something Be Done About Traffic Congestion, II Traffic
Quarterly, XXV (July 1971), p. 408.
2. ' ,As one
transportation analyst has pointed out,
Washington, D.C. especially lends itself to car pooling
since more than one-third of Washington's downtown em-
ployment is concentrated in Federal agencies. Agencies
often house hundreds, sometimes thousands, of employees
who have a common destination and standardized working
hours. Also...the Federal agencies frequently encourage
car pooling unofficially with bulletin boards, route
descriptions or a central point of inquiry.
408-409.
Ibid., pp.
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5-22
non-existent, and hence car pools are difficult to form.
For this very
reason, a number of new organizations are now promoting computerized in-
. 1
formation systems as one means of stimulating car pool format~on.
Use of a computer would be beneficial in two respects:
(1) by
accumulating a massive data bank of all potential car poolers (regardless
of location and work schedule considerations), and (2) by facilitating
a matching of feasible car poolers.
In a typical computerized system,
employees might be given a questionnaire to which they would specify their
home and work locations and schedule requirements.
The computer would then
search the data bank for feasible car pool formations.2
The extent to which an efficient information system could encourage
car pooling cannot be resolved at this time, absent any large scale tests
of computerized car pool systems.
However, one small study by the State
of California Department of Public Works was conducted for the San Francisco
1. "Operation Oxygen," a California group whose main purpose is to re-
duce smog by curbing the number of vehicles on the road, has succeeded
in encouraging car pools in Pasadena (where 500 employees of the Burroughs
Corporation are sharing rides) and at the State College campus in San
Bernardino (where 400 of the 2,000 students and teachers formed car pools).
In both cases, computers were used to identify people who lived(n the same
area but did not know one another.
2. Particularly if car pooling on any significant scale is envisioned, .. .'" J.
a computerized information system capable of matching large numbers of
shifting job and residential locations would appear required. Such a
system by itself would probably not suffice to sti~late car pool formation
on a large scale, but would be necessary if substantial car pooling were
encouraged by other means.
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5-23
area, and does suggest the potential of these systems.l
Although it
cannot be considered conclusive, the study tends to confirm the view that
such computerized systems alone would be of limited value.
In conclusion, riders who are not reasonably close neighbors at
home and at work cannot be expected to share cars.
And even where common
travel routes make car pooling feasible, more tangible incentives than the
desire to reduce congestion and pollution are likely to be necessary to
2
stimulate commuters to travel together.
Car pools may be encouraged,
however, by various measures involving selective application of motor ve-
hicle restraints (see Chapter 6).3
1. In March 1970, approximately 12,000 postage free cards were distri-
buted to commuters passing through the San Francisco Bay Bridge toll plaza.
A questionnaire contained on the card solicited interest in car pooling
and requested pertinent information for car pool matching. Slightly more
than 10 percent (1,250) responded to indicate their interest in car pooling.
The information was then key punched on computer cards and lists were com-
piled which matched resident and work area zip codes. Approximately one
month later, a total of 1,050 lists were formed, reproduced and distributed.
A return post card was then mailed with each list to the original respon-
dents who were asked to advise the Department of any success in their attempts
to form car pools. The result: 125 commuters responded, of whom only 32
indicated they had formed car pools, less than one-half of 1 percent of the
group studied. Information from California Department of Public Works,
Division of Bay Toll Crossings.
2. The failure of a campaign co promote voluntary car pools in 10s Angeles
in October 1971 helped to make this point. Despite considerable publicity
and efforts by more than 100 companies to organize computerized car pools,
the effort failed, probably because of the highly dispersed patterns of
origins and destinations of the commuters in the 10s Angeles area.
3. For example, where toll bridges or tunnels exist, fully occupied
vehicles may be given a faster or cheaper passage in peak hours. Such a
scheme was introduced o~ the San Francisco-Oakland Bay Bridge in December
1971. Cars carrying three or more passengers between 6 a.m. and 9 a.m. are
offered a toll-free crossing and a 10-minute gain in time through not having
to queue for tickets. The aim of the experimen~ as yet not attained, is
to increase the number of cars crossing the bridge with three or more people
on board from about 2,000 to about 3,000.
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5-24
People Movers
People movers may be defined as grade-separated systems of small
dimensions, operating at moderate to low speeds with continuing access
to the service at frequently spaced stations.l Capacities will probably
range from 2,000 to over 10,000 riders in the peak-hour, depending upon
the particular people-mover technology.
At the present time there is a
wide variation in the hardware and propulsion systems of people movers,
although all are electric and pose little, if any, problem for the immediate
environment.
Virtually all people-mover systems, however, involve new and
relatively untried technology; over the short-term, therefore, they will
be available only in relatively small numbers through demonstrations or
"first of a kind" installations.
The principal role of people movers is to move large volumes of
people to and from transportation facilities, and to provide distribution
routes in and around central business districts and other major activity
centers.
For example, they could be of major importance in moving motorists
from parkIn ride facilities to and from other activity centers in the
central business district and in providing for some separation of pedes-
trian and vehicle traffic, thereby affording more orderly and (hopefully)
more rapid vehicular flows.
.', -~..!:..r ,l
1. A large number of people mover concepts have been proposed and several
are currently in use. A typical system would consist of small (i.e., one
or two passenger capacity with room for parcels) automatically controlled
capsules. Passengers using the system would enter the capsule at one of
many sidings and push a start button. The capsule would be automatically
accelerated and merged into mainline traffic; deceleration would be done
automatically when the capsule is turned iRto a riding.
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Air Pollution Control Potential
Promising as the above improvements may seem individually, they
should not be allowed to obscure the larger reality.
Extensive review
I
of all recent evidence
leads us to conclude that public transport im-
provements alone hold little promise for major modal diversions.
There
are no prospects at all for attracting motorists to public transport by
minor improvements.
Only an all-out marketing effort, complete with
variable scheduling and great increases in express services, can even
hold present levels of public transport ridership.
Moreover, modal di-
version to public transport does not necessarily reduce motor vehicle
traffic.2
To have any appreciable effect on emissions, public transport
improvements must be combined with motor vehicle restraints (see Chapter 6
and the analysis of the Philade1phia-Lindenwold line in Appendix E).
1. The few oublic transport success stories of recent years (e.g., the
National City Lines in Rochester, New Yor~and the Reston, Virginia,
Charter Services) have been carefully marketed efforts that meet specific
consumer requirements and operate nearly door to door at nearly private
passenger car speeda. People have demonstrated their willingness to pay
higher fares for these services.
2. For one thing, modal diversion may consist of riders attracted from
one form of public transport to another (e.g., from bus to subway). When
new rapid rail systems were developed in Chicago and Toronto, diversion
occurred from the old bus or street car transit to the new systems with
little new or added ridership generated. See Martin Wohl, The Urban
Transportation Problem; A Brief Analysis of Our Objectives and the Pros-
pects for Current Proposals (Washington, D.C.: Urban Institute, March
1970), p. 13.
Another possibility is that public transport improvements cause
car pools to decrease in size as poolers shift into drive-alone situations
to take advantage of increased highway capacity. Similarly, if traffic
conditions improve to the point where substantial and obvious time savings
are possible, other motorists may modify their journey to work patterns to
take advantage of the new capacity. Or the additional capacity may be
"soaked up" by trips attracted away from other corridors in the area.
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5-26
Our major conclusion, therefore, is that improvements in public
transportation are a necessary but not sufficient condition for reducing
motor vehicle traffic (and hence, emissions).
Improvements are necessary
because restraining or restricting motor vehicle traffic in high pollution
areas of central cities will require substantially
better public trans-
k" 1
ma ~ng. Improvements
port service to provide an alternate means of trip
are not sufficient, however, since in the absence of accompanying motor
vehicle restraints public transport improvements will reduce motor vehicle
traffic only modestly, if at all.
Indeed, emissions may actually increase
where they are currently worst (i.e., in the downtown and other densely
developed areas).
Historically, the effect of good transit has been to encourage the
economic development of the CBD it serves.
When a new transit system is
installed, development tends to take place around the downtown stations
of that line.2 Development is especially intense at the node points --
where two or more lines cross.
Since ground rents are high -- due in
no small part to the new transit systems -- the new office buildings
1. In no U.S. metropolitan area is there at present a rapid rail or bus
system capable of satisfying all trip-making needs, even in theCBD. With
a few exceptions, the proportion of people riding transit (entering the
CBD on a typical weekday) tends to be less than 60 percent in most large
cities. For attracting the remainder expansion of existing taxi service
and the introduction of demand-responsive systems (e.g., taxi-bus) appear
to be the best alternative.
2. One can already see the high new buildings going up in San Francisco
and more high rise construction has been recently approved. In Washington,
the pressure is already on to lift building height limitations because they
are "inconsistent with the new subway system." Those concerned with traf-
fic congestion and air pollution may well watch these two cities during
the next decade to determine the effects of subway developments.
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5-27
also tend to be high.
As a result, more people tend to work in the
downtown than was previously possible.
Although a large number of new
workers probably take the new, convenient
1
centage will take their motor vehicles.
transit system to wor~some per-
The proportion of new motorists
may be small relative to transit users, but their absolute numbers are
important, particularly at peak hours.
Maximum Feasible Emission Reduction
Generalizations about public transport are always hazardous,
since
the industry serves patrons with diverse needs and in varied circumstances.
Caution is particularly valid when projecting the extent to which motor
vehicle emissions could be reduced from potential improvements in future
service.
It is clear, however, that public transport improvements alone
hold out little promise for major modal diversions, much less .a reduction
in motor vehicle emissions.
Our best judgment is that even extensive im-
provements (including some construction and renewal of equipment) would
be unlikely to reduce vehicle miles traveled2 (and hence emissions) by
more than 5 percent in any major metropolitan area.
To determine the reasonableness of this judgment, a special analysis
was conducted of traffic data along the corridor served by the Philadelphia-
Lindenwold line.
For a number of reasons, the Lindenwold Rapid Transit
Line probably represents the best commuter rail service this country has
1. They will be able to park
usually have. Typically, new
have more parking spaces than
in the basement spaces that new buildings
buildings built on a parking lot tend to
the original area.
2. Reference is particularly to vehicle miles traveled by light-duty
motor vehicles (e.g., the private passenger car).
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5-28
to offer.
Accordingly, it provides a good indication of the maximum
feasible emission reductions which would be possible from public trans-
port improvements.
In Appendix E to this report, we describe how the Lindenwold line
has combined speed, convenience and comfort at a moderate cost with an
aggressively marketed transit service aimed at meeting the competition
of the automobile.
We conclude, however, that although the line has
obviously made its mark on improving suburban rapid rail service, its
impact on reducing motor vehicle traffic (and concomitant emissions) is
less evident and more difficult to measure.
A reduction in motor vehicle
traffic directly attributable to the Lindenwold line has not occurred, at
least as reflected in available data.
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5-29
Institutional Feasibility
The problems of planning, organizing and financing public trans-
portation improvements are pervasive and complex, exceedingly difficult
to resolve and have received substantial attention in the voluminous
1
literature on urban transportation.
Provision of public transport has
probably been subject to regiona1ization more consistently than any
other urban service.
It is also more frequently provided by public
enterprises and special authorities than by general government departments.
On the whole, however, the administration of public transportation is also
often the most functionally fragmented of urban services.
Single purpose
agencies (the Toll Road Authority, Parking Authority, Transit Authority
or Airport Authority) abound, along with state and local government de-
partments of highways and traffic.
In many metropolitan areas, the search
for administrative solutions to transportation is also complicated by a
number of legal factors (e.g., governing eminent dommn and land acquisition)
as well as (in many cases) anachronistic public regulation of transit and
taxi services.
All the patterns are too complex for complete description
here, and in the following we only attempt, therefore, to sketch the most
salient issues.
Current Position of Public Transport
Although a number of institutional problems may impede, the
major obstacle to implementing public transport improvem~nts is simply
1. For some of the more important works, see bibliography attached to this
report.
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5-30
lack of money.
Appreciation of this problem requires recognition of the de-
clining financial position of public transport systems across the country.
In the past two decades, the transit industry has experienced a shrinking
market as the highway construction program advanced and as automobile
ownership increased.
In 1950, U.S. transit lines carried a total of
13.8 billion revenue passenger~.
By 1970, that total had diminished to
1
5.9 billion passengers -- a decrease of over 57 percent.
Furthermore,
the highway program -- in combination with other factors -- has encouraged
low-density land-use patterns with their dispersed origins and destinations.
Most of the transit industry has not been able to profitably service low-
density dispersed travel, and nationally most public transportation
2
systems have been operating with a deficit since 1963.
There is no available evidence that this long-term decline in
ridership (which has continued without deceleration in the past decade),
will either cease or noticeably slow down.
This means that in another
eight to ten years the smaller metropolitan areas will have only 10 to
15 percent of the public transportation ridership they demonstrated in
1. American Transit Association, 1970-71 Transit Fact Book, Table 5
(Washington, D. C., 1971), p. 6. The 1970 total is a preliminary figure.
2. Ibid., Table 1, p. 4. Transit problems have been compounded in
recent years by inflation, lack of capital to replace aging equipment
and rising labor costs. In the latter connection, it is important to
understand that mass transit is a highly labor-intensive business --
about 65 percent of transit operating costs are associated with labor.
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5-31
1950; while metropolitan areas between 500,000
1
60 to 75 percent of their 1950 ridership.
and 2,000,000 will have
It must also be concluded from all available evidence that tradi-
tional. rigidly routed, scheduled transit service does not meet the needs
of a vast majority of people in metropolitan areas under 2 million people.
And even in the larger metropolitan areas, rail (and particularly bus
systems) have been undergoing fierce competition with motor vehicles
since at least the end of World War II.
At the present time, in terms
of comfort and convenience (and,for some trip purposes, cost) the personal
passenger car is unequaled by any public transport technology now in use.
Within this context of deficits, failing operations, poor equipment
and declining service, and given the attractions of the private passenger
car in terms of privacy, convenience, freedom of movement and the like,
the reasons for the difficulty of enticing Americans out of their
automobiles become clear.2
It is equally apparent that if public
1. Institute of Public Administration, "The Present Condition and
Characteristics of the Transit Industry and How they Evolved," draft
report, Washington, D. C., September 1971. (Mimeographed.)
2. It has been seriously estimated that public transit riders would have
to be paid 50~ or more per trip to induce a majority of motor vehicle
commuters to give up their private passenger car in Chicago's circum-
stances. (See Leon N. Moses and Harold F. Williamson, Jr., "Value of
Time, Choice of Mode, and the Subsidy Issue in Urban Transportation,"
Journal of Political Economy, LXXI (June 1963), pp. 247-264. More recently,
a Gallup poll indicated that 81 percent of U.S. citizens use the automo-
bile for the journey to work. This percentage, which is, of course, even
higher for other trip purposes, has been confirmed by surveys taken by the
Bureau of Census. A recent census survey indicated that 82 percent of
workers traveling more than one-fourth of a mile from h~e use the ~uto-
mobile to commute to work. See U.S. Department of Commerce, Bureau ot the
Census, Home to Work Travel Survey, cited in Automobile Manufacturers Associ-
ation, 1971 Automobile Facts and FiKures (Detroit, Mich.: Automobile Manu-
facturers Association, 1971).
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5-32
transport is to compete effectively, its services must be significantly
improved.
Rapid Rail Systems
Construction of new systems. As indicated earlier, only the ~qil
systems for San Francisco (BART) and Washington, D.C. (Metro), (of th.
cities examined in this study) could potentially be opened for service
in the short term (by 1977).
Both systems could be expedited somewhat by
additional (mainly federal) funds, since in both cases the politically
difficult and time-consuming task of acquiring rights-of-way and road
bed facilities has been accomplished.
Additional funding, however, is
by no means clearly in view, either from the Urban Mass Transportation
Administration's Capital Grant program (see below) or from local matching
funds.
Even with more funds, accelerated construction would probably
be constrained by the limited supply of experienced contractor and super-
vision capabilities.
Most public transport systems depend upon government subsidies
to cover part of their operating expenses, and are totally incapable of
financing the complete cost of capital improvements from user revenues.
As a result, if the improvements in public transportation are tq be~ade.
funds for such purposes must be derived primarily from loans and grants
at one or more levels of government and/or borrowing on agency credit,
usually with government approval.
(The exception, of course, concerns
highway programs which are financed largely from earmarked gasoline taxes.)
The Urban Mass Transportation Assistance Act of 1970 (84 Stat. 962)
commits the Federal Government to obligate $10 billion by 1982 for capital
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5-33
grants to improve transit systems.
It authorizes $3.1 billion in contract
obligations over the first five years of the program.
However, as of early
1972, this $3.1 billion fund for capital improvements was already entirely
allocated.
These federal funds (i.e., the $10 billion obligated for capital
improvements) may be compared with our estimates of the capital requirements
for public transport improvements in the six cities under study (see Intro-
duction and Summary of this report, "Preliminary Cost Estimates for Public
Transport Improvements").
Our estimates indicate that about $13.8 billion
would be required in terms of capital investment if existing plans plus some
moderate improvements (such as people movers) are implemented in the cities
of New York, Chicago, Washington, D.C., Los Angeles and Denver.
These esti-
mates must be considered conservative since they do not include the scope of
changes (i.e., substantial improvements) which apparently would be needed
to meet national air quality standards by 1975.
If (as is provided for under the 1970 Urban Mass Transportation
Assistance Act) the Federal Government were to contribute two-thirds of
these capital investment costs, over 90 percent of the total $10 billion
available for the entire country would be expended for just the six cities
under study.
If more and better public transport is to be made available,
1
a significantly greater federal commitment would clearly be required.
1. Department of Transportation Secretary John A. Volpe recently requested
Congress to allow part of the federal money now earmarked for highways to be
used for public transportation. The money would be taken from the Highway Trust
Fund, a special part of the federal budget that is financed by highway user tazes
and now can be spent solely for highways. Under Mr. Volpe's proposal $1.5 million
from the Fund would be made available to urban areas for public transport in the
fiscal year beginning July 1, 1973. The amount would rise to $1.85 billion in the
next fiscal year and to $2.25 billion after that.
The proposal, however, appears certain to face substantial opposition in
Congress (especially among some members holding key committee positions), and
were it to be enacted the approval of six Congressional committees would probably
be required.
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5-34
Extensions of existing systems.
As in the case of constructing new
systems, the most important institutional problem in extending new rapid
transit lines is additional funding, funding which does not appear avail-
able at the present time.
Operational and service improvements.
The operational and service
improvements identified earlier for rapid rail systems include:
(1) reducing
fares, (2) increasing comfort, cleanliness and safety, (3) increasing
schedule frequency, (4) providing park 'n ride, and (5) improving fare
collection.
Since extensive and continuing subsidies would still be re-
quired, even after paying for such improvements, the major institutional
problem is simply that at present there is no source of operating subsidies,
except from state and local taxes.
The problem of obtaining funds to cover
large operating deficits of transit operation applies equally to rail and
bus systems.
In most cases, only the Feder~ Government appears capable
of covering these operating deficits, let alone of funding major operational
improvements.!
Without extensive federal assistance, improvements in
1. Particularly during the last decade, state and local subsidies for public
transportation have increased substantially. Important examples include
New Jersey, where the State, through its Department of Transportation,
administers aid programs for commuter rail and bus transit services;
Pennsylvania, where the Commonwealth has continuing a progLam of operat-
ing assistance for mass transit, coupled with a state program for capital'
grants which works in tandem with the Federal Capital Grants program; and
New York City, where public transportation in the New York City region is
provided by the Metropolitan Transit Authority (MTA) , the Port of New York
Authority Trans-Hudson Corporation (PATH). and seven privately-owned bus
companies operated in Manhattan and Queens. A number of other states and
localities have also been moving to support public transportation. Last
year, for example, the California Assembly approved a bill to extend the
state sales tax on gasoline to raise approximately $129 million annually
to subsidize public transportation.
Probably the most dramatic program of local support for public trans-
port in recent years was the approval by Atlanta voters in November 1971 of
a new regional sales tax that will not only underwrite much of the construc-
tion costs for a new rapid rail system, but will also subsidize fares (the
current fare on buses, 40~, will be cut back to l5~ soon because of the
new tax).
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5-35
public transportation for most metropolitan areas are unlikely to be made
because of fragmented state and local jurisdictions, various organizational
and managerial deficiencies, and inadequate available financial resources.
For all practical purposes, no federal funds are available at the present
time to subsidize operating deficits, let alone to finance major improve-
ments.1
2
There appears to be some support in Congress for such subsidies,
and Administration proposals have been presented.
Therefore, the feasi-
bi1ity of federal funding for transit operations and improvements will depend
in large measure on the outcome of the ensuing political process.
In addition to availability of funds, a federal subsidy to transit
operators would pose a number of administrative problems including:
(1)
service units (e.g., passenger miles traveled) are difficult to define,
measure and audit; (2) unless the conditions for federal subsidies are
spelled out very specifically, money may be dissipated by labor demands
and wasteful management practices; and (3) it is far from clear who would
1. Some federal funds are available through a few demonstration projects,
but these are largely limited at present to poverty areas not well served
by motor vehicles. Hence, the potential for reducing motor vehicle use
through public tranportation in these areas is exceedingly small.
2. Several attempts have been made recently to pass legislation to ptovide
subsidies for operating deficits of mass transit systems. A typical bill
would provide grants of up to 50 percent of any mass transit operating de-
ficit over a period not to exceed three years. As of early 1972, an approach
actively under consideration in Congress would provide operating subsidies to
mass transit systems by authorizing a simple,two-paragraph addition to Sec-
tion (8) of the Mass Transportation Act. The amendment would expand the
$10 million program of capital grants to transit systems and would be included
as a small part of the Housing and Urban Development Act of 1972, a measure
more than 500 pages long. Funds for the subsidies would come from the $500
million in transit funds now impounded by the Administration and from a multi-
billion dollar increase in the program's long-term contract authority which,
by law, must be extended in 1972.
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5-36
be the appropriate administering agency (e.g., a federal department, state
or local governments, an area-wide transportation authority).
Bus Systems
Most of the improvements identified earlier for improving bus service
require little or no capital investment.
Extensive and continuing operat-
ing subsidies, however, would be required, an~ to this extent, the unavail-
. 1
ability of these funds (other than from federally funded projects or state
and local taxes) constitutes the principal institutional problem.
1. In addition to the Urban Mass Transportation Administration's demonstra-
tion program (as already mentioned), another federal program should be noted.
The "Urban Corridor Demonstration Program" is an attempt to combine High-
way and Urban Transit projects in a package approach to deal with severe in-
stances of urban traffic congestion. The program was initiated in January
1970 by the U.S. Department of Transportation with the stated purpose of
drawing upon various transportation program resources to focus on specific
congested corridors. Possible funding sources include UMTA grants for
facilities, equipment, and research studies as well as Federal Highway Ad-
ministration grants for TOPICS and related construction projects. (Some
limited funding was also made available for this specific program.) General
guidelines were stated to delineate the type of congested corridors the
program was to affect (e.g., peak hour travel speeds of 20 mph or less and
traffic vo1ume-to-capacity ratio approaching one during the peak hour).
In outlining the program, DOT suggested a number of improvements
which could be considered by cities in applying for funding. These included
fringe parking near transit facilities, demand-activated collection systems,
traffic restraints, exclusive bus lanes, signalization schemes to favor
buses, and transit fare and parking price experiments. A prospective
city could propose any combination of such efforts to be applied to a
particular corridor.
Secretary of Transportation Volpe announced on July 1, 1970,contracts
totalling almost $2 million to be awarded to eleven cities for preliminary
planning of their projects. Preferential access to streets and freeways
for transit and exclusive bus lanes were the predominant strategies, pro-
posed in some form by eight of the cities. Other proposals accepted in-
cluded a system of satellite terminals with parking and heated bus shelters
(Cincinnati), collection-distribution systems utilizing feeder buses and
improved parking facilities (Philadelphia) and a new bus terminal design
and operation system (Washington, D. C.).
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5-37
Some capital investment would be required for one of the most pro-
mising improvements in bus services (i.e., the operation over exclusive
or preferential lanes of more buses on non-stop express schedules between
line-haul entry points and downtown areas).
Modest outlays would be re-
quired in the event that these services require modification of existing
roadway facilities, or special grade-separated rights-of-way (perhaps by
taking over abandoned or under-utilized railroad beds).
Use of existing highways or streets for express bus lanes may be
obtained in a matter of months, as has been demonstrated in several recent
experiments, two of them in New York City (the Lincoln Tunnel approach and
the Long Island expressway to Queens-Midtown Tunnel approach).l
In the Queens-Midtown Tunnel case, the estimated annual cost of the
venture is $150,000.
The cost is presently being borne by the New York
City Department of Traffic in using its own personnel and equipment, al-
though, Traffic Commissioner Theodore Karagheuzoff has said that he hopes
the plan will be financed by the Federal Government eventually.
1. In the latter case, a special lane was set aside for express buses on
the congested Long Island expressway. The new lane is along the last two
miles of the expressway before it enters the Queens-Midtown Tunnel and was
made by reversing the direction of one of the three eastbound lanes. The
lane is in use for buses from 7:00 a.m. to 10:00 a.m. on weekdays, after
which it is turned back to an eastbound lane.
Recent reports indicate that the express buses running along this route
are at 80 percent capacity and carrying about 6,500 people for an average of
about three and a half minutes on the two miles to the tunnel. Motor vehicles
traveling the same distance in the three westbound passenger lanes have been
averaging about eighteen minutes. A similar reversing of one lane during rush
hours has been in effect in New Jersey since December on the approach to the
Lincoln Tunnel.
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5-38
For all but the largest cities federal funds appear necessary
for the implementation of exclusive bus lane improvements. 1
Some improved
busways may be financed with funds from the Federal Highway Administration,
but these funds would have to be taken from the regular construction pro-
grams,
which are hard fought after and closely watched by highway interest
groups.2
The Urban Mass Transportation Administration is taking some steps
towards financing busways, but there still have not been a great many ap-
plications.
Until more interest is expressed and pressure brought to bear,
the UMTA will probably not expand this program.
Aside from lack of subsidy funds (and agreement upon ways of ad-
ministering these) additional institutional problems in implementing im-
provements are:
(1) the functional fragmentation of agencies providing
1. As noted elsewhere, however, these capital investment requirements
are relatively modest when compared to most rapid rail improvement
programs. See Introduction and Summary of this report "Preliminary
Cost Estimates for Public Transport Improvements."
2. In addition, some local departments of highways and traffic (parti-
cularly in medium- and small-sized cities) may not be presently prepared
to propose and/or sponsor bus system improvements. Traffic engineers
in these departments may be opposed to disrupting their way of doing
things, preferring instead to rid their streets and highways of "dirty,
noisy and smokey buses" to make room for private passenger cars. As
indicated, these attitudes, of course, are by no means uniform. In some
of the larger cities local departments or highway and traffic have taken
the lead in facilitating express bus service over exclusive busway or pre-
ferential lanes.
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5-39
transportation services, (2) the historic hostility in many areas between
local governments and transit operators (e.g., in Washington, D. C., between
Washington Metropolitan Area Transit Authority, the District Government
and D.C. Transit System, Inc.) over matters of money and management, and
(3) the poor marketing efforts mounted by most transit operators.
In the latter connection, the transit industry may be characterized
as less confident and more resistant to change than most.
For decades,
transit operators have been oriented towards servicing a steadily diminish-
ing captive ridership under conditions of public regulation which leave
little room for initiative.
Declining ridership, technological stagna-
tionl and rapidly rising labor costs have led to the approval of higher
fares (under the assumption that operations should be paid for "out of the
fare box"). Ironically, service has increasingly been for those least able
to pay.
However, even the fare increases, coupled with service cutbacks,
have failed to keep most transit systems out of the red.
As a result the
industry has been unable for the most part to attract dynamic young managers.
Some well managed systems can be foun~but they are far from the norm.
Taxi and Demand-Responsive Systems
The extension of taxi services to reach their full or even reasonable
potential would entail substantial institutional changes (with resp~ct to
licensing, franchising, rate making and so forth).
Among the most pressing
changes which could be considered are the establishment of free entry for
taxis (found at present among the metropolitan areas we are examining only
the use of computer-aided routing and dispatch.
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in Washington, D. C.), the use of differential peak and off-peak rates and
1. Substitution of buses for streetcars has been the only real technological
change in transit during the past century.
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5-40
The major institutional problem concerning demand-response systems
d . 1
is simply the lack of a computer-aided emonstrat~on. The Urban Mass
Transportation Administration is currently sponsoring two demand-respon-
2
sive demonstration systems, although neither is computer-assisted. Studies
of the potential market, however, have concluded that in order tu assure
a sufficient demand for these systems, computer-aided routing and dispatch
should be an essential part of the service.
In the judgment of these
researchers, work on demand-responsive systems has progressed to the point
where a demonstration of a computer-aided system is desirable now.
Numerous local communities have expressed a strong desire
to play host to such a demonstration. The purchase of
equipment, hiring and training of drivers, etc., would
require a lead time of about six months from the day of
the decision to fund the initiation of service, but tech-
nology is ready.
At the six month point from decision day, it would be
possible to have ten vehicles in operation. In twelve
months, twenty-five vehicles could be in operatio~. In
eighteen months, the number could be fifty or more. Fur-
ther development of the computer programs will be required
to support larger systems. Within a decade, however,
there is no reason why systems involving thousands of
vehicles should not be technically feasible and cost- 3
effective where large metropolitan markets justify them.
1. Demonstration is required to determine the public acceptance and use of
the service, profitable operating costs, the most appropriate collection
and distribution, and so forth.
2. In the first demonstration, twelve small vehicles of up to 15 passen-
ger capacity will carry commuters to the Haddonfie1d, N.J. station of ~he
new Philade1phia-Lindenwo1d line. Initially vehicles will be manually
dispatched from many origins to one destination, although a scheduling
algorithm is to be developed for later application.
3. Massachusetts Institute of Technology, "Dia1-A-Bus" (paper presented
by Alan Altshuler and Daniel Roos at the Fifth Meeting, Consultative
Group on Transportation Research, Organization for Economic Co-operation
and Development, Directorate of the Environment, Paris, October 1970), p. 99.
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5-41
Federal funding for a computer-aided demand-responsive demonstration, how-
ever, appears unlikely until the present limited experLments have operated
long enough to make preliminary judgments.
The implementation of demand-responsive systems will probably face
serious institutional problems, largely legal in nature, but which also
relate to the usual resistance to change by parties who presently have ex-
clusive franchises to provide transportation services.
From the standpoint
of regulatory law, demand-responsive systems would combine characteristics
of both the taxicab and the bus.
Generally speaking, if these systems are
established as private bus companies and must meet existing regulations and
laws pertaining to bus franchises, difficult procedural problems will have
to be solved.
If demand-responsive systems are established as taxicab
service~ fewer problems of regulatory law exist -- at least for most juris-
dictions.
On balance, in many jurisdictions some statutory, even consti-
tutional, relief may be required before extensive operations of a demand-
responsive system may be tmplemented.
Car Pools
There do not appear to be significant institutional or technical
problems with car pooling schemes, and they could be made available in a
relatively short period of time.
As indicated earlier, however, short of
very powerful incentives, there is little ground for believing that car
pools alone could be effective in reducing motor vehicle emissions.
Tan-
gible incentives would probably require some public funds, and in the
event of use of restricted lanes, some additional encorcement costs may
be imposed.
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5-42
People Movers
The institutional problems in implementing people movers could be
important.
Several years will probably be required to solve problems ex-
pected to emerge among designers, environmentalists, and building owners
over what is the most appropriate .manner in which to install people
mover systems.
There may have to be some use of public ac~isition
powers, and unquestionably a considerable amount of air and other right
compensation to property owners.
Although people movers could be put
underground, costs would probably double from the currently estimated
$2 million to $3 million per mile (fully installed).
Consequently, tun-
neling represents a relatively costly solution.
Most people mover systems
would have to be "public" and substantial amounts of money would have to
be raised.
Again, federal financing would probably be required.
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C HAP r E R
6
MOTOR VEHICLE RESTRAINTS
Definition of Terms
In the present chapter we consider various measures which could
reduce to some degree motor vehicle usel in high air pollution areas.
These
measures, termed motor vehicle restraints, consist of controls over parking
and/or road use, whether by administrative action or pricing policy, as
summarized in Table 6-1.
Subsequent sections discuss the air pollution
control potential of these motor vehicle restraints and their institutional
2
feasibility.
Regulating Parking
The location, amount and use of parking can be controlled by adminis-
trative action (i.e., without public intervention in pricing).3
In most
metropolitan areas there are three categories of vehicle storage capacity
1. The motor vehicles to be restricted or restrained could consist of private
passenger cars, transit vehicles, taxis, trucks or some combination thereof.
2. In our view, the following measures would be either impractical to imple-
ment or ineffective over the short-term in restraining traffic in large metro-
politan areas: (1) limiting vehicle ownership, fuel or mileage by regulation;
(2) completely banning the use of major vehicle categories (e.g., private
passenger cars, taxis, trucks) in major portions of any large metropolitan
area; and (3) imposing higher sales taxes and/or registration fees upon vehicles
used in particularly high pollution areas. Accordingly, we do not give these
measures attention here. For a discussion elsewhere, see Institute of Public
Administration, Governmental Approaches to Automobile Air Pollution Control
(Washington, D. C.: 1971). Chapters 2 and 3.
3. Administrative action to reduce motor vehicle storage capacity, however
would usually result in increases of market-set parking rates, which, in turn,
would have a reinforcing effect.
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Table 6-1
MOTOR VEHICLE RESTRAINTS
Restrnint
Results
Description
Experience I
Regulating Psrking
Pricing Parking
Regulating Road Use
Pricing Road Use
Reduce by administrative action motor
vehicle storage capacity, off-street
and/or on-street parking in or near
high pollution areas.
Impose parking prices for off-street
an~/or on-street parking in or near
high pollution areas.
Reduce by administrative action road
network used (e.g., through pedestrian
malls, vehicle free zones) in or near
high pollution areas.
Impose charges for motor vehicle use
of selected portions of urban street
networks in or near high pollution
areas
Some large cities have moved to control
the construction of additional parking
garages in downtown areas. However.
other off-street parking (e.g., spaces
in co~rcial buildings made available
to employees) are usually outside of
municipal control. On-street parking
has been controlled in relatively few
areas, except during peak hours.
Increased off-street parking charges
have occurred in virtually all metro-
politan areas as demand exceeded sup-
ply. However, nominal charges (well
below those for off-street parking in
the same vicinity), are still in effect
for most on-street parking. Moreover,
most off-street spaces are still al-
located outside the market mechanism
(e.g., to employees, residents).
Parking meters are still the major
method of charging for on-street space.
Some 24 U.S. cities have introduced
such schemes (mostly on an ex~ri-
mental basis) in recent years.2
Toll collection facilities in and
around Baltimore, Boston, Chicago,
Jacksonville, Kansas City, Miami,
New York City and Philadelphia. Other
techniques for imposing road pricing
are currp.ntly available, as summarized
in text, but have only been tried in
limited applications or not at all.
Would reduce motor vehicle use in high pol-
lution areas, and to some extent to and from
them. This reduction, particularly if com-
bined with controls over on-street parking,
could also significantly improve traffic flow.
However, through and circulating traffic would
not be reduced, and might even be encouraged.
~
I
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Would reduce or eliminate motor vehicle use in
high pollution areas, and to aome extent to and
from t~ However, would create host of trans-
portation problems (e.g., fringe parking, gooda
delivery, improved access and internal circula-
tion) and possibly greater congeation and aC4
companying motor vehicle emisaions on immediatel-
adjacent local streets and arterials.
1. Most experience with motor vehicle restraints has been motivated by objectives other than air pollution control (e.g., reducing congeation,
minimizing motor vehicle-pedestrian conflicts, enhancing the esthetic and commercial appeal of central city areas, and, in the caae of psrking
charges and toll collection, raising revenuea). However, particularly in some large cities growing concern sbout automobile air pollution has
given rise to increasing public support for curbing motor vehicle use.
2. Atchinson, Kan.; Cincinnati, Ohio; Williamsburg, Pa.; Columbus, Ohio; Dennison, Texas; Denver, Colo.; Fresno, Calif.; Grand Junction, Colo.;
Kalamazoo, Mich.; Knoxville, Tenn.; Miami, Fla.; Miami, Okla.; Minneapolis, Minn.; Montevideo, Minn.; New York, N.Y.; Patteraon, N.J.; Pomona,
Calif.; Providence, R.I.; Riverside, Calif.; Sacramento, Calif.; Stamford, Conn.; Tulsa, Okla.; Urbana, Ill.; Washington, D.C. See C. Kenneth Oraki,
"Vehicle-Free Zones in City Centers," (Cologne, Germany: Organization for Economic Co-operation and Development, October 1971).
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6-3
which conceivably could be controlled by regulating parking:
(1) on-street
parking (available for short periods only where metered); (2) publicly
available off-street parking (whether publicly or privately provide~; and
(3) privately available off-street space.
Present policy (though not necessarily enforced) in most municipalities
is to prohibit on-street parking whenever and wherever it obstructs traffic
movement, typically along major arterials during commuting hours.
Rationing
the rest of on-street parking is usually accomplished by parking meters or
other enforcement aids such as permit stickers and (in Europe) parking discs.
Off-street parking (especially in retail areas) is now encouraged in most
municipalities by providing municipal garages and/or requiring parking space
in new commercial buildings.
Both policies have made available all-day park-
ing and thus served to stimulate motor vehicle use, particularly where the
municipal spaces are provided below cost (i.e., subsidized).
In most metropolitan areas, some private property owners provide public
parking for profit at market-set rates.
Other private owners provide parking
for their residents, employees and customers, either free or for charge.
However, public, for charge
parking services may not usually be offered
without appropriate land-use permits.
In the United States there have been
few attempts, and none successful, to restrict use of private prop~rty for
parking of employees, customers, or residents.
Present policies for publicly available parking (both on- and off-
street), ho~ever, are now under review in many metropolitan areas, and in
some cases have been changed to take account of the limited existing street
, 1
system and storage capacity.
Some years ago, for example, the New York City
Planning Commission "probably set a precedent for large cities by refusing
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6-4
to approve the construction of several parking garages to provide short-term
parking at reduced rates for business and shopping purposes in midtown
1
Manhattan."
More recently, the same city has increased its enforcement of
on-street parking limitations.
According to a recent account, each week
some 1,000 motorists have their illegally parked vehicles towed away, resulting
in a
$75 fine.2
Other cities have moved to limit existing on-street parking
at certain hours to residents only, in an attempt to discourage parking on
city streets by residents of outlying districts.
Boston, for example, now
limits all night-time street parking to city residents who display a special
sticker on their windshield.3
Pricing Parking
Another approach to controlling the use, and to some extent, the amount
and location of motor vehicle storage capacity would be through actions which
raise parking prices to a level sufficient to discourage motor vehicle use at
selected times in specified areas.
Parking charges could be raised for the
entire day (e.g., a relatively flat rate per hour) or for periods related to
peak hours (e.g., high peak hour charges combined with lower off-peak charges).
1. Lyle C. Fitch and Associates, Urban Transportation and_Public Policy
(San Francisco: Chandler Publishing Company, 1964), p. 150. "The reason
cited," this source observes, "was that these additional traffic generators
would unduly further congest street traffic, and might actually reduce the
total volume of movement into and out of the midtown area. The argument
did not impress advocates of the midtown garages, including the midtown
depsrtment stores. The Planning Commission would have been on stronger
ground if it had been able to buttress its arguments with figures; unfortu-
nately research techniques for producing such data have not yet been devised."
2.
"The Ban-the-Car Movement," Newsweek (January 4, 1971), p. 42.
3.
Ibid.
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6-5
Furthermore, such increases could be limited to selected days (e.g., Monday
through Friday).
The potential effects of such pricing policies have been
summarized as follows:
A relatively high flat rate per hour will have the effect
of discouraging all-day parking, especially by regular
commuters, more short-period parking, since the demand for
short-pgriod parking for businesses or shopping purposes
is apparently less elastic than the dem3nd for regular
all-day parking. However, if the charge is sufficiently
high to reduce pgak-hour congestion to acceptable levels,
it may be excessively high for other periods, and discourage
driving into the central area for shopping or business
during periods when streets are well able to handle the
traffic. In such cases, lower charges for off-peak p3rking
are indicated. Low-cost short-term parking is frequently
provided by merchants or public authorities, but with no
reference to an overall policy of efficient traffic control.1
In principle, local governments might increase p3rking prices in
either of two ways.
First, a municipality might regulate prices for
pub1ic1y-
available
parking spaces as it would regulate any public service utility
regulation having the effect of raising parking prices.
Or, municipalities
could impose parking taxes, either with a flat rate or selectively as to
2
location, day of the week or elapsed parking time. The municipal taxation
method appears particularly preferable where local revenues will be required
for improved and expanded public transport, which would be required if any
major motor vehicle restraints on private passenger cars are imposed.
1. Lyle C. Fitch and Associates, Urban Transportation and Public Policy
(San Francisco: Chandler Publishing Company, 1964), p. 150.
2. In October 1970, the city of San Francisco imposed a 25 percent tax
on parking fees in non-municipal parking garages. The Washington, D. C.,
City Council is currently considering a similar tax. In both cases ad-
ditional municipal revenue has been the primary objective, although air
pollution control has been advanced as a complementary goal.
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'I
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6-6
Regulating Road Use
In this category are a number of measures (e.g., pedestrian malls,
vehicle-free zones) which, in effect, reduce the usable street netWork in
high pollution areas.
As a recent article points out, it has been only
in the late 1960's that these measures have really gained momentum.
Within the last several years the number of cities which
have introduced traffic bans (on an experimental or p~rma-
nent basis) has grown impressively. In Germany alone,
tWenty-eight cities have introduced traffic restraints and
auto-free zones since 1967. A large number of pedestrian
areas have also made their appearance in Dutch, British and
other Europ~an towns. Perhaps the most widely publicized
efforts have been those of Tokyo, Rome and New York City.
Each of these cities has excluded traffic on a part-time
experimental basis from portions of busy central areas;
Tokyo from the Ginza, Shinjuau, Ikebukuro and Asakusa
Districts, Rom3 from a number of its most famous piazzas,
New York City from midtown sections of Fifth and Madison
1
Avenues.
In most cases, however, these projects have not had air pollution control
as a major objective.
The same source indicates that the scale of existing measures to
regulate road use can vary considerably, and in most cases has been ad-
2
mittedly modest.
More recently, however, larger scale projects have been
attempted, primarily in Europe.
The Germ3n city of Essen, for example,
has recently extended its netWork of pedestrian streets
and m3l1s to create a car-free zone nearly 1 km. in
length and nearly 300 meters in width. The Hague and
DUsseldorf both possess traffic-free zones which span a
1. C. Kenneth Orski, "Vehicle-Free Zones in City Centers," {Cologne, Germ:my:
Organization for ECQnomic Co-operation and Development, October 1971), p. 3.
According to an inventory of such measures appended to this article, road
restrictions are now being tried in some 156 cities around the world including
24 in the United States.
2.
Ibid., p. 7.
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6-7
total of 2.4 km. and 3.4 km. of streets, respectively.
Copenhagen's Str,get, a highly successful venture in
traffic exclusion, is 1,080 meters long; a further
extension in 1968 has added another 300 meters of adjoining
streets to the pedestrianized area. By far the most ambitious
scheme i8 that of the city of Vienna, which is contemplating
the creatton of a vast traffic-free central zone with a
diameter of about 1.2 km. In as much as the area would b~
too large to be served exclusively by movements on foot,
non-polluting taxis and mini-buses running on liquid gasl
would be allowed to circulate within the exclusion area.
In addition to their scale, regulattri~ road use can be varied according
to the degree of re8tricti~~ desired.
Proceeding to increasingly restrictive
measures, one could have:
(1) private pgssenger cars eKcluded during certain
hours of the day or days of the-week (e.g., 10:00 a.m. to 4:00 p.m.); (2) som~
private pgssenger cars excluded but others (e.g., those operated by area
residents or doctors on call) permitted; (3) all private passenger cars
1. C. Kenneth Orski, "Vehicle-Free Zones in City Centers" (Cologne, Germany:
Organization for Economic Co-Operation and Development, October 1971), p. 9.
A large-scale series of experiments with motor vehicle restraints was recently
conducted in Marseilles, France, where a total ban on parking was imposed in
the core of the city, covering about .25 square kilometers. At the same
time, 9 kilometers of exclusive bus lanes were added to improve existing bus
service,and all public transport was provided free of charge during one
day to test the response of free service. For details see, C. Kenneth Orski,
"Car-Free Zones and Traffic Restraints: Tools of Environment Management,"
Report prepared for the 51st Annual Meeting of the Highway Research Board
(Paris, France: Organization for Economic Co-Operation and Development,
1972) .
Vehicle-free zones have also been implemented in Florence (which has
banned cars from a 40-block area in its historic center); Munich (which has
created a large traffic-free zone as part of its preparations for the Olympic
games~ and Brussels (which is conducting a 7-month experiment to ban parking
altogether in the Grand'P1ace, except for tourists, buses and trucks during
limited delivery hours). . New York City is currently contemplating several
vehicle-free zone possibilities, the most ambitious of which would convert
a IS-block segment of Madison Avenue between 42nd and 57th Streets into a
permanent pedestrian mall.
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6-8
excluded from specific zones (e.g., pedestrian malls).
Obviously, both
the scale of the measure and the degree of restriction should be tailored to
. ,. 1
meet a given C1ty s C1rcumstances.
One of the most interesting approaches to regulating road use (an
approach which combines motor vehicle restraints with measures to bypass
thru traffic) has been tried in Bremen, Germany, and in the Swedish city of
Gothenburg.
In recent years, these cities have been divided into quadrants,
and physical barriers have been constructed between these quadrants, thus
making thru traffic within the city impossible (except for emergency vehicles --
fire, ambulance and so forth -- and public transport, which are permitted to
pass between quadrants).
In effect, each quadrant has become a self-
contained precinct with only local circulation allowed.
All other tra f-
fie must use a circumferential road, leaving and entering each quadrant at
designated locations.
This, in effect, reduces the use of vehicles for
, '--, lk' 2 A
downtown circulation and 1ncreases wa 1ng. s indicated in a subsequent
section of this chapter, the Gothenburg approach appears to have achieved
important air pollution reduction results, as well as other ancillary benefits.
Pricing Road Use
Road pricing to raise revenues (not to control traffic) currently
exists in the United States and abroad, both by paying for highway construction
1. In addition, selective restrictions could be applied by type of vehicle.
For example, German cities with pedestrian precincts 'commonly employ a ban an
commercial vehicles making deliveries between the hours of 10:00 am and 8:00 pm.
In a number of cities, thru traffic is required to use bypasses or
specified routes, and in some residential neighborhoods, commercial traffic
is excluded all together.
2. For further details on the Gothenburg approach see Chapter 4. "Bypass
Thru Traffic."
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6-9
through fuel taxesl and through special tolls imposed for high-cost bridge,
tunnel and freeway facilities.
The toll collection approach is in wide use at present.
Applied by
public authorities (and occasionally local governments) operating river
crossings or high capacity highways, tolls are levied to recover the costs
of these particular facilities from the motorists actually using them.
In
contrast to fuel taxation, whereby motorists pay "averaged" prices for road
use, toll collection imposes differing charges which can be varied according
to the cost of the specific facility and how many times it is used.
While tolls are usually thought of in connection with turnpikes and
intercity highways (which are closed to all users except those paying the
toll), and are further known to be a relatively inefficient means of raising
highway funds in lieu of taxes, the fact remains that tolls are widely levied
in high density urban locations.
Consequently. they are certainly a feasible
means of road pricing in order to control the use of motor vehicles in areas
of high automobile air pollution.
All experience with toll collection, however,
has been for revenue raising purposes, not to control motor vehicle traffic.
Thus, toll authorities have traditionally adjusted rates so as to maximize
revenues, not to reduce traffic.
- ,
Among the large cities with toll facilities
on major entry points for high capacity highway links leading in towards the
1. As a meanS of controlling traffic, fuel taxation would be a very blunt
instrument and hence, inappropriate except for very large areas. Furthermore,
fuel taxation which makes no distinction between peak and off-peak hours and
high-and low-cost facilities would be objectionable on other grounds.
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6-10
CBD are Boston, New York City, Philadelphia, Baltimore, Chicago, Kansas
City, Jacksonville and Miami.l
In addition to the above, a number of other methods for imposing
road pricing are possible, including a congestion pass approach (e.g., using
stickers for tickets), manual or automatic scanning, metering, and so forth.
Although a congestion pass approach shows promise for near term application,2
1. In considering how toll collection facilities might be used for pollution
control purposes, perhaps the New York City case (where traffic volumes are
highest) is th~ most instructive. All feur of the highway connections to
Staten Island (population approximately 500,000) are tolled. Of the ten
crossings over the Hudson and East Rivers linking Manhattan to the New Jersey
and New York counties, six are tolled. In addition, one of the bridges over
the much smaller Harlem River is tolled. Two additional East River crossings
between the Bronx and Queens are tolled. In sum, within the city of New York,
and amidst conditions of extremely high volumes and congestion, there are
thirteen toll collection points, all located on arterial and expressway
facilities providing for major access or linkage traffic. In addition, the
highest capacity highways in New Jersey, New York and Connecticut which
both link the city to and serve between major suburban nuclei are tolled.
These facilities include the Turnpike and the Garden State Parkway in New
Jersey, the Saw Mill River Parkway, New York State Thruway, Hutchinson River
Parkway, and New England Thruway in the state of New York, and the Wilbur
Cross and Connecticut Turnpike in Connecticut. In fact, the only toll-free
parkway going north from New York City is the Bronx River Expressway.
Using these existing toll facilities for road pricing with the more
pervasive coverage which would presumably be required for reducing motor
vehicle miles traveled is one possibility. From an air pollution control
point of view, if tolls at all of these existing facilities could be col-
lected'without excessive congestion (and emissions), there is no doubt about
the feasibility of using controls for this more expanded kind of road. p~i~~~g!
2. Under this approach motorists could be charged according to place (and
perhaps time) of car use. Concentric control zones could be drawn to coincide
with areas of traffic density and air pollution. In a given metrQPolitan area
the central business district might constitute the inner zone, central city
an intermediate zone, and outlying suburbs a third. Motorists could purchase
distinctive stickers which license them to drive and park in a specific zone.
Assuming congestion and pollution were most severe at the center, the sticker
cost could be highest in the central zone and decrease for outlying ones. A
congestion pass permitting vehicle use in the central zone would permit vehicles
to be driven in areas of less stringent control, although the reverse would not
apply. Any vehicle without an appropriate sticker would be fined or towed away.
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6-11
most other methods presuppose continuous or intermittent monitoring of all
vehicles on the road and will probably not be ready for widespread application
before the end of this decade.
Air Pollution Control Potential
At some point on the scale of regulation or price increase, motor
,:;
vehicle restraints of the sort discussed above would unquestionably reduce
traffic volume in downtowns or any other;s.elected area.
Traffic congestion
and its c~ncomitant air pollution (no~ito mention noise pollution and other
undesirable motor vehicle externalities) would also be reduced.
Ava ilable
air quality monitoring data from the experience to date have been limited to
sampling concentrations on streets and/or near major roadways, but indicate
that motor vehicle restraints can have a powerful effect on improving local
condi tion s .
As would be expected, the most dramatic reductions have been achieved
from total ban.
During the first phase of the Marseilles experiment noted
earlier, mean values of carbon monoxide dropped from 18.8 to 3.6 ppm when
all vehicles except taxis and buses were excluded from the central area. 1
1. The average of seven readings per day (8:00 a.m. to 6:00 p.m.) at four.
IOdations. Source: Association pour la Prevention de la pollution atmos-
pherique, Comite-Provence, cited in C. Kenneth Orski, "Car Free-Zones and
Traffic Restraints: Tools of Environmental Management," Paper prepared for
Presentation at the 51st Annual Meeting of the Highway Research Board (Paris,
France: Organization for Economic Co-operation and Development, 1972), p. 6.
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6-12
During the second phase of the experiment, when~parking was totally banned
in the core of the city, but traffic was allowed to move freely, mean values
1
went from 18.8 to 11.6 ppm.
Data
to determine the effects of motor vehicle restraints on a larger
scale (e.g., concentrations in the central city or on a metropolitan area-
wide basis) are not available.
'1',,1
Consequently, we must confine the following
to some general comments about the air pollution control potential of various
motor vehicle restraints.2
1. The average of seven readings per day (8:00 a.m. to 6:00 p.m. at four
locations. Source: Association pour la Prevention de la pollution atmos-
pherique. Comite-Provence, cited in C. Kenneth Orski, "Car Free-Zones and
Traffic Restraints: Tools of Environmental Management." Paper prepared for
Presentation at the 51st Annual Meeting of the Highway Research Board (Paris,
France: Organization for Economic Co-operation and Development, 1972), p. 6.
2. Apart from a few small-scale experiments (e.g., the closing of part of
Madison Avenue in New York City) the only experience with limiting motor
vehicle use on a large scale in the United States was during the Depression
and World War II. Data on motor vehicle registration and transit ridership
during that period indicates the effects of an adverse economy on motor
vehicle and transit use.
With the commencing of World War II, the construction of highways, mass
transit vehicles and private passenger cars was almost completely halted.
Furthermore, gasoline and tire rationing were in effect. What with these
drastic restrictions on automobile use and the high pace of industrial
development, transit ridership dramatically increased. In 1945, patronage
stood at over 23,000,000,00~ or almost twice that of 1935. However, conclu-
sion of the Second World War signaled the end of this reprieve for the tr~n~it
" ',n,"/Y~~)'
industry. More roads and streets were built; the war economy swelled the purse of
consumers and manufacturing might, acquired by the auto industry in producing
war materiel, was shifted to motor vehicle manufacturing. The result was that
in 1946, there were 28,000,000 vehicles registered; in 1956, over 54,000,000
were registered; and today, there is almost one vehicle for every two people
in the United States. Not only has the transit industry not withstood the
c~petitive assault. but it has found itself being held back by one of the
major service deficiencies of the motor vehicle system -- congestion. For
further discussion, see Institute of Public Administration, "Evolution of
Urban Public Transportation in the United States," Appendix A to "The Present
Condition and Characteristics of the Transit Industry and How They Evolved,"
draft report (Washington, D. C.: Institute of Public Administration, 1971).
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6-13
Regulating and Pricing Parking
Since motor vehicles coming into high pollution areas must park
somewhere (unless they are traveling through) their movement may be
restrained by reducing (or making more expensive the use of) parking
facilities.
From the standpoint of air pollution control, the use of
parking controls has some limitations.
Thru and circulating traffic,
which sometimes constitutes a relatively large proportion of total traf-
fie, even during peak hours, may not be restrained; indeed, if congestion
in central areas is reduced, such traffic may even be encouraged. 1
The
effectiveness of parking measures in reducing emissions may also be
limited by difficulties in controlling all parking space2 and various
political obstacles in implement,ing comprehensive parking controls. 3
1. As noted in Chapter 4, the solution to
appear to be a bypass for thru traffic via
means. However, if thru drivers choose to
parking controls will not deter them.
the thru traffic problem would
circumferential routes or other
use central city streets instead,
Circulating traffic consisting of taxis, trucks and other service vehicles,
can together account for the majority of vehicle miles traveled in some
downtown areas (e.g., midtown Manhattan). To cite another example, some com-
muters may find it desirable to have a member of the family drive them to work,
drop them off, and return home with the car. If a similar sequence occurs at
the end of the day, parking controls could conceivably result in doubling the
vehicle miles traveled of some motor vehicles. Although there are no empirical
data to allow an estimation of the additional vehicles miles traveled which
would be generated, experienced traffic engineers maintain that cordon counts
on rainy days are approximately 15 to 20 percent above what they are at other
times, for similar reasons.
2. Private parking provided free of charge accounts for half of total parking
space in the CBD's of many major metropolitan areas. Comprehensive parking
controls over already existing space provided by private firms and government
agencies would be difficult to enforce and would probably require new legislation.
3.
These problems are discussed below under "Institutional Feasibility."
-------
6-14
In sum, there are marginal parkers in any area who may be removed
by making parkins spaces scarcer and/or more costly.
The scarcer and higher,
the greater the number removed.
However, the above limitations suggest that
parking measures are probably but a second-best solution for purposes of air
pollution control, the optimal one being to regulate or price motor vehicle
use (i.e., entry, exit and operating time in heavily polluted areas).
Regulating and Pricing Road Use
In principle, the application of road use restrictions and pricing
(e.g., a charge for motor vehicle use in certain areas -- and perhaps during
certain times -- of high pollution concentrations) would be the most effective
means of restraining motor vehicle use.
Some available evidence suggests that road use restrictions (specifically
traffic bans) are indeed effective measures for reducing motor vehicle air
pollution, at least locally, at the street level.
In New York City, the
closure of Fifth Avenue to traffic in tle summer of 1970 resulted in a
reduction of carbon monoxide concentrations from 30 ppm to 5 ppm.l
In Tokyo, Japan, exclusion of motor vehicle traffic from the Ginza,
Shinjuku, Ikebukuro and Asakusa Districts resulted in important carbon
monoxide reductions, as summarized in Table 6-2.
Preliminary evidence also
suggests that the Gothenburg approach, described above, is effective:
1. Unfortunately. however, close inspection of the New York City data suggests
several reasons to be less than sanguine about the actual emission reduction
achieved. For one thing, monitoring for the experiment was inadequate. For
another, it appears that although carbon monoxide concentrations were reduced
on those streets closed to traffic, the concentration levels were higher for
immediately adjacent avenues which bore the brunt of additional congested
traffic movement.
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6-15
Goteborg's experience has shown that this traffic
management approach can reduce circulation by as much
as 50 percent. Although the scheme has been in opera-
tion only since August 1970, it has already had a number
of beneficial environmental effects: there has been a
reduction of 5 percent in accidents; mean concentrations
of CO in the Central Business District have lowered from
30 ppm to less than 5 ppm, and noise levels went down from
75 dba to 72 dba.l
As noted earlier, these measures appear effective in the immediate areas
affected, although a number of larger issues are unresolved.
For one thing, the appropriate scale for such efforts is far from
c1ear-, as suggested above with respect to the New York City experiment.
Nor is it clear whether total trips to some boundary of the restricted area
could be reduced.
Isolated pedestrian malls may reduce local air pollution
concentrations but fail to achieve an important improvement in air quality
for the entire CBD.
Indeed, air quality may worsen because of congestion on
adjacent arterials.
On the other hand, large scale projects cause their own kinds of
prob lems :
Closing streets to traffic on a larger scale very soon
begins to pose a host of transportation-related problems;
fringe parking, improved access, goods' delivery, traffic
rerouting and internal circulation. It is no accident
that existing pedestrian precincts seldom exceed 400 to
500 meters in length; this may be the maximJm distance
which it is felt an average shopper is willing to negotiate
on foot. Beyond it, some mechanized circulation system may
be necessary. 2
These transportation-related problems, of course, would have to be worked
1. C. Kenneth Orski, "Vehicle-Free Zones in City Centers," (Colgone, Germany:
Organization for Economic Co-operation and Development, October 1971), p, 10.
2.
Ib id., p. 8.
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6-16
Table 6-2
EFFECT OF TRAFFIC BANS ON CARBON MONOXIDE CONCENTRATIONS IN TOKYO
ppm of CO
Sampling Station Before 1 After 2 Remarks
Ginza
Okura Building 3 14.2 2.9 Average of 5 hourly
Victor Building 5.5 2.4 readings
Gas Hall 5.4 2.3 (1:00 p.m.-6:00 p.m.)
Shinjuku
Kome Theatre 3 2.2 1.2 Average of 8 hourly
Yamaichi Sec. Bldg. 9.8 2.3 readings
Electro-board 11.3 2.3 (11:00 a.m.-7:00 p.m.)
Ikebukuro
Parco 9.5 3.5 Average of 7 hourly
Seibu Dept. Store 6.7 3.0 readings
Sumitomo Bank 5.7 4.2 (12 noon-7:00 p.m.)
Asakusa
Rokku 1.7 1.9 Average of 9 hourly
Ward Office Branch 3.2 2.2 readings
(10:00 a.m.-7:00 p.m.)
Source: Traffic Division, Metropolitan Police Department, Tokyo, Japan
(courtesy of Shinji Nishida, Chief, Traffic Regulations Section) as cited
in C. Kenneth Orski, "Vehicle-Free Zones in City Centers," (Cologne,
Germany: Organization for Economic Co-operation and Development, October
1971), p. 5.
1.
Before:
July 26, 1970 (wind velocity:
3.9 m/s)
3.3 m/s)
2.
After:
August 2, 1970 (wind v~locity:
3. Survey by automatic recorder; in all other locations, hourly sampling
and analysis by infra-red method.
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6-17
out on a case-by-case basis, taking into account the scale of the project,
the existing street system, the availability of public transport and other
city-specific factors.
In conclusion, road pricing, to the extent it can be implemented
in a satisfactory manner, offers a more effective way to reduce emissions
than parking controls or restrictions on portions of the street network.
Sufficiently high cnarges would reduce the total number of motor vehicle
trips made, but if charges were adjusted by day of the week and hour of
the day, they could be selectively applied and would not affect vehicle
operation considered unobjectionable (weekends, evenings, and perhaps
during off-peak hours).
Finally, and perhaps most importantly, substantial
revenues would be generated for the improvement of public transport which
would seen a concomitant if urban mobility is not be seriously reduced. ~
The practicability of implementing road pricing remains an untested
proposition.
Nevertheless, the air pollution control potential of road
pricing (as well as other possible ancillary benefits) argu~strongly
for further exploration of the concept to indicate whether and how such a
system could be instituting to control motor vehicle use in the core areas of
central cities. 1
1. Among the issues which ought to be addressed are: (1) what would be the
public's response to road pricing; (2) what kinds of operating costs would
be associated with alternative collection syste~; (3) what would be the
feasibility and impact of differential pricing policies; (4) what would be
the social and economic consequence8 (e.g., on downtown business and employ-
ment and on individual road users); (5) what kinds of public transport service
would have to be provided; (6) what kinds of institutional problems (e.g.,
coordination among neighboring jurisdictions) might be encountered. If
initial indications are favorable, a demonstration would be desirable to
determine the effects of road pricing schemes on congestion and air quality.
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6-18
Maximum Feasible Emission Reduction
The emission reduction potential of motor vehicle restraints is a
function of the severity of those restraints.
If widespread road pricing were
implemented, or if overall parking space were significantly reduced, motor
vehicle miles traveled (and hence, emissions) would decrease.
Conversion
of large central city areas into vehicle-free zones could have an even
more dramatic effect.
Such extensive restraints on motor vehicle use in
major portions of any metropolitan area, however, are clearly not feasible
within the next five years.1
Estimates of the emission reductions which might be reasonably
expected from less severe restraints are not easily arrived at since no
systematic study has been made of the price elasticity of motor vehicle
2
use.
Our best judgment is that (taking parking controls as a surrogate
for motor vehicle restraints) if parking rates were doubled for a city such
as Washington, D. C., the reductions in motor vehicle traffic (and emissions)
would be minor, probably not to exceed 5 percent.
Under a comprehensive
parking control program (whereby existing rates for all spaces were tripled
or quadrupled) an overall reduction in motor vehicle traffic of from 20 to
25 percent might be achieved (assuming, as always, that public transport
would be importantly improved).
Such a program would appear to be the upper
limit of practical action at present.3
1. In addition to practical problems noted above, the political opposition
(e.g., from automobile owners' associations, downtown merchants) would be
enormous. Furthermore, it is difficult at this time to see where strong poli-
tical support for complete bans would come from. For further discussion see
below, "Institutional Feasibility."
2. Price elasticity here refers to the percentage change in
accompanying a change in the cost of using the motor vehicle
operating or time costs).
motor vehicle use
(either investment,
3. Further discussion of these judgments, as well as a review of the data
upon which they are based can be found in Appendix F of this report.
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6-19
Institutional Feasibility
Any assessment of the institutional feasibility of motor vehicle
restraints must begin by acknowledging the significant shift in public senti-
ment toward the automobile in recent years.
In a recent book, Aspirations
and Affluence, a te~m of analysts from the University of Michigan Survey
Research Center observed that studies carried out in the late 1960's "indicate
that car has increasingly become a means for serving important ends, rather
than the highly priced possession it once was in the United States and still
is in much of Europe."l
These changes in attitude may make Americans less
attached to their cars and hence more amenable to motor vehicle restraints
in some core areas of central cities.
Attitudes alone, however, will not
appreciably affect motor vehicle use, at least in the short term.
Motorization rates continue unabated and there is a rising demand
for second and third cars (although many of these are smaller American cars
or imported vehicles).
Likewise, the proportion of households without a
car continued to decline in the 1960's and is now only about 20 percent.
Finally, and most relevant to this study, the travel patterns of all
metropolitan areas are increasingly characterized by dispersed trip ends,
which cannot be readily served by most public transport systems.
Americans
mgy appear less enamored of their automobile, but they are hardly less
reliant on it.
Nevertheless, it does seem reasonable to assume that public sentiment
will continue to grow in favor of curbing at least some motor vehicle use
1. Dr. George Katona ~ al., Aspirations and Affluence, cited in Dan Cortez,
"Autos: A Hazardous Stretch Ahead," Fortune, April 1971, p. 69.
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6-20
in congested areas of large cities.
At present most motorists probably
realize that the downtown area dictates a high level of control over
motor vehicle movernsnt.1
A number of developments -- relatively slow
traffic movement and the many frictions caused by circulating traffic,
parking and unparking, truck loading, and signalization, and heavy traffic
volume -- already affect road users in downtown areas by restricting their
freedom.
Informal evidence such as exists seems to indicate that growing
numbers of motorists are coming to regard curbs on motor vehicle use in
some areas of central cities as inevitable, indeed desirable.
At the official level, public discussion of motor vehicle restraints
in the United States has changed dramatically during the past decade.
In 1961,
when the possibility of regulating motor vehicle use (through road pricing) was
first advanced to the Federal Government in a national urban transportation
study, one of the sponsoring agencies refused to release the report.2
--
1. Unfortunately, these statements are highly speculative since we are
aware of no available behavioral research which tests driver reactions
to various motor vehicle restraints. Most drivers probably accept and
recognize the need for such restraints, at least in core areas. However,
a sizeable number of drivers place their personal interests first and
are willing to violate even existing regulations, to the detriment of
drivers and pedestrians. If motor vehicle restraints are considered for
implernsntation, it would be useful to develop information describing the
best possible way of implementing these to obtain the highest level or
acceptance by road users.
2. A book based upon this study by the Institute of Public Administration,
however, was subsequently published in substantially rewritten form. See,
Lyle C. Fitch and Associates, Urban Transportation and Public Policy
(San Francisco: Chandler Publishing Company, 1964).
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6-21
Less than a decade later, statements in favor of curbing motor
vehicle use in some central city areas have been made at the highest level
of the U.S. Department of Transportation.
For example, in his keynote
address to the 1969 Pittsburgh conference on urban transportation, Department
of Transportation Secretary Volpe stated:
America must now accept the fact that the private
automobile will not forever be the absolute monarch
of our core cities. How and when this change will
come about, we cannot yet say. But the means are
not altogether obscure. We could make mass transit
so attractive that habitual drivers would leave the
highways. Some are convinced that dial-a-bus and
other personalized modes will provide a breakthrough.
We could tax cars entering the city in order to pay
for police services, traffic control, parking, road
repairs, and so on.
More and more, the hallowed right to jump into
our cars and drive them anywhere we please is being
tallied against other community and individual
values -- the need for elbow room, clean air, stable
neighborhoods, more parkland, and many others. So
far, we have sought sheer mobility above every other
consideration; other needs have been neglectedl and
the social equation is clearly out of balance.
Growing interest in regulating motor vehicle use is also evident in
Congress, where on July 15, 1971, a bill was introduced in the House of
--
1. Proceedings, Fourth International Conference on Urban Transportation,
Pittsburgh, Pennsylvania (March 10, 11, 12, 1969) cosponsored by the
Pittsburgh Urban Transit Council and the U.S. Department of Transportation.
Keynote Address by the Honorable John A. Volpe, Secretary, U.S. Department
of Transportation, p. 8. Among other things, this statement was significant
because it was the first major policy statement of the Secretary upon
assuming office. More recently, see DOT press releases of August 27, 1970
and February 16, 1971.
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6-22
Representatives to allow cities with a population over 200,000 to collect
tolls or user fees on the freeways within their jurisdictional boundaries.
According to its author:
The purpose of this bill is to significantly reduce
automobile pollution, which now accounts for more
than 50 percent of all air pollution in our cities.
This legislation would also provide an added source
of income to cities and would require that commuters
help pay their fair share for the services in the
city which they use.l
The significance of these statements is that public discussion at the
official level has proceeded to a point where motor vehicle restraints are
now seriously contemplated in many quarters.
Details on how these motor
vehicle restraints would be applied in specific cities have been developed
in only a few cases,2 but in the coming five to ten years one can expect
such plans to proliferate.
In subsequent sections we assess the institutional
feasibility of the more promising of these measures.
1. Statement by the Honorable Les Aspin, Congressman of Wisconsin, in the
House of Representatives, Thursday, July 15, 1971, Congressional Record,
proceedings and debates of the 92nd Congress, 1st Session.
2. Among the jurisdictions furthest along in this regard is New York City
which is currently considering a substantial reshuffling of midtown traffic
patterns to meet federal air quality standards. The proposals, which are in
various stages of consideration, include: (1) conversion of Park Avenue f1Dm
34th Street northward, Central Park West and all the Central Park drives to
northbound traffic up to llOth Street during noon and evening rush hours; . ..
(2) the establishment of express bus lanes on Madison, Second and Third Avenues
and 48th and 49th Streets; (3) a halt to taxi cruising in midtown, to be re-
placed by creation of depots and taxi stands; (4) control of truck deliveries
in midtown to limit them, for instance, to between 10 a.m. and noon and between
2 p.m. and 4 p.m., and to organize fuller loads at depots, perhaps on West Side
piers; aad, (5) creation of pedestrian malls on Lexington Avenue, Broadway,
48th and 49th Streets. See, "Midtown Traffic Reshuffling Proposed," New York
Times, December 13, 1971, p. J.
-------
6-23
Regulating Parking
From the standpoint of institutional feasibility, there appear to be
at least three principal problems with the use of parking regulationsl as a
means of pollution control.2
First, there would be great difficulty in controlling all parking space,
particularly already-existing space provided for employee parking by private
firms and government agencies.3
As indicated in Table 6-3, this "uncontrolled"
parking accpunts for about 45 percent or more of total parking in many CBD,s.4
5
New space may be limited by zoning and building restrictions. as in the center
1. Public regulation, if any, of parking varies considerably from city to
city. However, parking is generally an unregulated service, except insofar
as municipally-owned parking facilities may serve to regulate prices.
2. The following discussion draws upon Lyle C. Fitch and Associates, Urban
Transp~rtation and Public Policy (San Francisco: Chandler Publi~hing Company,
1964), pp. 150 ff.
3. The present discussion concerns primarily off-street parking; curb-side
parking, however, would also have to be controlled.
4. Unfortunately, parking data were not available for any of the six
cities for this study, although with the exception of WashingtDn, D. C., there
is no reason to assume the data would be substantially different.
5. In most metropolitan areas, it has been traditional practice -- in an
attempt to secure more adequate off-street parking -- to require that a
minimum number of parking spaces be provided in or adjacent to new buildings.
A reversal of this policy, which has been achieved only with some difficulty
in most jurisdictions, is bound to be disputatious and time-consuming, and
in any event would have little overall effect from an air pollution point of
view during at least another decade. Regulation of private property would be
another possibility. However, there have been very few attempts, and none
successful, to regulate the use private owners make of their property for private
parking. Private owners, for example, may provide parking spaces, free of
charge, for their employees and customers, although they may not run a
public, tor charge, parking service without appropriate land-use permits.
Regulating private provision of parking, especially for employees on the pre-
mises, would be a substantial new intervention in the private use of land,
and would take considerable time to introduce and implement. No cities could
be realistically expected to have an effective parking regulation of this
type by 1977.
, 'I
"
-------
6-24
Table 6-3
WORKERS PARKING IN THE CBD:
FREE AND PAID
Parked Free
Percentage
of Total
Paid
to Park
Percentage
of Total
Total
Philadelphia 14,568 57 11,801 43 24,649
Boston 14,397 48 15,791 52 30,188
Baltimore 7,313 46 8,582 54 15,895
Seattle 8,835 54 7,575 46 16,410
Milwaukee 23,092 74 7,983 26 31,075
Source: Wilbur Smith and Associates, Patterns of Car Ownership, Trip
Generation and Trip Sharing in Urbanized Areas, prepared for U.S. De-
partment of Transportation, Bureau of Public Roads (New Haven, Connecticut:
Jure 1968).
-------
6-25
of New York City, but if controls are imposed only an those having no access
to private spaces, discrimination is introduced.
The social and political
consequences would have to be evaluated in each case.
Second, public action
to restrict the supply of space may afford excessive profits for parking
operators by allowing increases in market-set rates.
Capturing these excess
profits for public purposes would be politically difficult in many cases
(e.g., where parking lots in garages are operated predominantly by large firms).
This suggests that taxes are a much more acceptable means of raising parking
rates.
Third, a policy of regulating parking space would encounter the staunch
opposition 0f all those who would be brought under control, a not inconsid-
erable force.
And there would always be pressure for special arrangements,
protection of "grandfather rights" and so on.
Again, this suggests the
desirability of the pricing approach.
No parking program of regulation would
be anywhere near 100 percent effective, while a comprehensive parking space
tax might reach 85-90 percent of all off-street spaces.
Pricing Parking
Imposing parking charges would be subject to some of the same in-
stitutional problems indicated above.
However, it appears unquestionable
that municipal corporations can either regulate prices for parking (as in
the case of a public service or utility), or impose taxes upon parking
which would have the effect of raising parking prices.
Raising parking
prices would be politically difficult, and would certainly involve con-
frontations between those raising charges and those whose interests are
directly affected (e.g., retailers and office building owners).
-------
6-26
Generally speaking, parking pricing appears preferable to parking
regulation, in that the former can be differentiated according to impact
(e.g., to discourage parking during peak hours but not for business pur-
poses before and after peak hours).
It is doubtful that the same ends could
be gained and the same degree of control achieved (e.g., encouraging midday
use) by enforceable regulatory restrictions.
Furthermore, taxes appear
to be a more attractive alternative because they supply municipal revenues
which are a.lways badly needed ard will be particularly so in tl'E event that
important public transit improvements are required.
Regulating Road Use
Road use restrictions would limit the use of motor vehicles by
direct, enforced, administrative action.
Correspondingly, they are dependent
upon police powers (or other enforcement) for their effectiveness; and this
would appear to be a major institutional problem.
From the legal standpoint,
it appears that all municipalities have the authority to regulate road use,
and in the event that existing authority were in some way inadequate, it
could probably be obtained.
Important legal problems, however, could well
arise from court challenges by abutting property owners, who might claim that
the value of their property had been reduced by limiting or preventing vehicular
access without due process of law.
Conceivably, some municipalities might
have to make compensatory pgyment for such cases.
Pricing Road Use
Generally speaking, road pricing would encounter political and legal
problems similar .to those indicated above.
As noted earlier, some techniques
-------
6-27
~re available for imposing road pricing.
The mechanics of implementing
road pricing, however, are probably much less a problem than gaining wide-
spread public acceptance to limit "freedom of the road," even in areas
of high air pollution.
-------
C HAP T E R
7
WORK SCHEDULE CHANGES
Definition of Terms
In the present chapter, we consider changes in established work
schedules (e.g., work staggering and the 4-day week).
Both measures
tend to spread work trips to and from major CBD employment centers
more evenly over time, thus thinning out traffic at the height of rush
hour and smoothing flows.
In the case of the 4-day week, weekly
commuting trips could be cut by a fifth, thus reducing total vehicle
miles traveled.
Focus on work trips to the CBD can be justified for three reasons.
First, in most cities the journey to work accounts for the bulk of peak
hour traffic, hence by considering work schedule changes we are often
dealing with the single most important travel pattern at those times.
Second, because work trips are concentrated at peak hours, a reduction
and/or temporal redistribution of trips would do more to reduce conges-
tion (and accompanying emissions) than measures taken at other periods.
Finally, the difficulties in-developing schedule changes to modify trips
for other purposes (e.g., shopping, business, recreation) are so great
to preclude this possibility, at least for the short term.
Work schedule changes can be grouped into two
1
staggering and the 4-day week.
broad categories:
work
The first makes no modification
in length of the working day (i.e., elapsed time between authorized
start and finish times, now currently 8 to 8-1/2 hours for most employees).
However, starting and stopping times are shifted somewhat (e.g., instead
1.
Both approaches are summarized in Table 7-1.
-------
Table 7-1
WORK SCHEDULE CHANGES
Name
Effect
Definition
Experience
1.
Stabgeredl
t10Urs
2.
4-Day week
Change in work hour schedule where-
by employees in a given employment
center shift starting and stopping
times somewhat, but within a rela-
tively short range (e.g., instead
of 9 to 5, from 8 to 4). No change
in length of working day required;
any shift in the morning is generally
matched by a corresponding evening
shift.
Reduction of work week to four days.
Generally, work week still consists
of same number of hours as before,
but with longer working days. Some
noticeable trend to 35-37 hour work
weeks as employers experience in-
creases in productivity unaer new
work schedules.
Implemented in some
60 American cities
during World War II.
Current projects in-
clude a number of
federal agencies in
and around Washin-
ton, D.C. and some
70 firms in Lower
Manhattan.
Since 1969, approach
has been receiving
considerable attention
in the United States.
As of late 1971, 658
firms have converted
to this schedule. Con-
version rate is now 4
firms per day nationwide?
Spreads traffic peaks.
Increases vehicle speeds.
Reduces number of weekly
work trips by 20 percent.
Daily reductions range from
none at all to two-thirds,
depending on rotation of 4-
day week. Spreads traffic
peaks. Increases vehicle
speeds.
-J
I
N
1. A variant of the work staggering approach, called "gliding work hours" (Glei tende Arbei tsei t"), is being
tried in Germany to provide congestion relief. This is essentially a "self-staggering" approach, with no fixed work
schedule modifications. Rather, employees choose their work hours within an established time frame. Major German
firms which have shifted include Messerschmitt-Bolkow-Blohm with 7,000 employees in Munich, Lufthansa in Cologne and
the Federal Ministry of Transport in Bonn, as well as some 2,000 other firms. In the German experience, several
of the larger employers have lengthened work days to 11 hours and allowed employees (who must punch time clocks)
to put in 8 hours within an II-hour period (i.e., select arrival and departure times within a 2-hour range at their
own discretion). Thus, as with work hour staggering, the intent is to allow travel before or after peak hours
(as well as to ease the strain on internal resources, elevators, parking lots, etc.).
2. Personal conversation with Riva Poor, March 1972. Riva Poor edits and publishes the authoritative news letter
on the 4-day week, ~~~r's Workweek Letter (Cambridge, Mass.).
-------
7-3
from 9:00 a.m. to 5:()(' p.m., from 8:00 a.m. to 4:00 p.m.).
The second modi-
fies the overall working day by requiring longer daily hours, but for one
less day per week.
Although the following discussion of work hour staggering is
generally relevant to "gliding time" (see note to Table 7-1), a few important
differences should be noted.
First, employer concern for operating effi-
ciency will probably be greater under the gliding time approach, since
it has greater potential for economic disruption.
Second, and of import
for purposes of air pollution control, experience with gliding work hours
has shown that only minimal changes tend to occur in travel patterns, and
that these are generally to earlier hours.
These two factors, of course,
minimize the extent to which "gliding time" can spread the peak.
In a study
conducted by two large employers in Germany (after 13 months of operation in
one case and nine months in the other), it was discovered that only 20 per-
cent of the employees changed their hours from those previously worked.
In
both cases, the predominant shift was to earlier hours.
It appears that,
in addition to personal value preferences, a shortage of parking space for
those arriving late was the underlying factor forcing shifts to earlier hours.
Air Pollution Control Potential
Spreading journey-to-work traffic (and its concomitant congestion)
over peak hours could contribute significantly to reducing motor vehicle
emissions in cities. During these two
1
roadway capacities are most strained.
short periods of the day, existing
Average vehicle speeds dwindle to
i
I
1. It is not particularly meaningful to use maximum daily capacity as
a measure of capacity since one peak-hour may account for more than 10
percent of total daily travel. Conversely, almost no trips may be made
during other hours (e.g., between midnight and dawn).
-------
7-4
less than 10 mph in many CBDs, and engine operating efficiency is further
reduced by a large proportion of idling and stop-and-go traffic.
In contrast,
capacity for most off-peak hours is in excess of traffic demand.
This very
uneven distribution of trips over time suggests the desirability of "spreading
out" the periods of peak utilization, thereby distributing traffic more
evenly over time and improving traffic flows.
In cities where work trips con-
stitute a substantial portion of peak hour trips (e.g., 60 to 70 percent),
a spreading out of work trips could conceivably afford substantial traffic
relief.
Changes in work schedules (which determine to a large extent the
departure and arrival times of vehicles in congested areas) could pro-
vide the means for distributing work trips more evenly over time.
From
an air pollution control standpoint, the resulting peak hour traffic
would probably be more important for alleviating maximum one-hour carbon
monoxide concentrations (the averaging time for federal secondary air
quality standards) than eight-hour concentrations (the averaging period
for federal primary air quality standards).l
However, any reduction
in peak hour traffic will generally improve traffic flows and hence
result in reduced emissions.
Traffic flows tend to improve because
demand will be more evenly spread over existing capacity.
In addition,
there will be fewer traffic frictions in CBD areas as parking lot ingress
and egress times are more uniformly distributed, and turning movements
become less disruptive.
This potential of work schedule changes is
suggested in Figure 7-1, which displays the estimated percent of people
starting work in the Manhattan CBD.
1. Work schedule changes seem particularly appropriate for cities where
morning winds are slow and the atmosphere generally stable, conditions
that inhibit the dispersal of pollutants.
-------
7-5
Fi\Sure 7-1
1
ESTIMATED PERCENTS OF PEOPLE STARTD!G IWRK I~, ;.1A~HATTAN CBD
oIt
40
36
32
28
[-<
z
~1 24
U
p~
~
Jl< 20
16
12
8
4
3/+.5
---------------
EQUALIZED
TEt-1PORAL
- - - - - - - - REDISTRIBUTION
OF TRIPS
7:30
7:45
8:00
8:15
8:30
3:45
9:00
9:15
9:30
TIME
1. Lawrence B. Cohen, Work Staggering for Traffic Relief: An AnalYBis
of Manhattan's Central Business District (New York, Praeger, 1968),
p. 163.
Concentration of work trips around 9 a.m. implies a corresponding
concentration (i.e., congestion) of motor vehicles at this hour. However,
for reasons discussed later, it is not necessarily correct to assume a
"one-to-one" time relationship between work start schedules and traffic
congestion. In the case of Manhattan (used here solely for purposes
of example) very few work trips to the Manhattan CBD are actually made
by private passenger car. Starting times are probably more widely dis-
tributedin New York City than elsewhere.
-------
7-6
As shown in Figure 7-1, a total of 82.9 percent of the work force
starts between 7:30 and 9:30 a.m., with the principal concentrations (in
descending order of importance) occurring at 9:00, 8:30, 8:45, and 8:00 a.m.
Distribution of this traffic uniformly over the five half-hour time intervals
would make optimal use -- from a traffic operations and air pollution con-
trol standpoint -- of existing roadway and transit capacity.
For example,
using data cited above, if 82.9 percent of work force starts were equally
divided by give, there would be 16.6 percent in each one half-hour interval
(a level represented by the dotted line).
Distribution of work force starts
would not have to be uniform, however, for significant gains to be ,realized.
For present purposes, it is sufficient to say that within the five intervals
outlined above, there is considerable latitude to facilitate re-scheduling
and effect transportation relief of varying degrees.
In addition to improving traffic flows, the 4-day work week could
contribute to reducing motor vehicle emissions in another and perhaps more
important way; by reducing total work trips.
Conceivably, each commuter
could reduce his journey-to-work travel by two trips per week under a 4-day
week, and an approximate 20 percent reduction in vehicle miles traveled (as-
sociated with the journey to work) could be achieved.
Furthermore, if the
working week is extended one day (i.e., Monday through Saturday, as is fre
quently observed with 4-day schedules), improvements in traffic flows could
be even more considerable.
Staggering Work Hours
Assuming work staggering could be implemented -- an assumption
which appears reasonable on the basis of available studiesl -- how
1. Previous experience and recent experiments in the United States and in
Germany indicate that work hour staggering is feasible. For further dis-
cussion, see below, "Institutional Feasibility."
-------
7-7
effective would work staggering be in reducing motor vehicle emissions?
Little has been attempted in the way of systematic analysis of actual
experience under staggered hours.
Most after-the-fact evaluations go
only so far as to indicate that "congestion levels on the streets were
deemed bearable" as a result of the program. 1
Other studies, such as
one for New York City,2 concentrate almost exclusively on mass transit
(as opposed to motor vehicle traffic) congestion relief as a measure
of effectiveness.3
The Lower Manhattan Study, however, did seek to
obtain vehicular counts at the Brooklyn-Battery Tunnel and Battery
Parking Garage.
Little change was observed at these locations as the
result of staggered hours, primarily (the authors indicated) because
the number of participants in the program at the time of the study
accounted for only a small proportion of total journey to work trips
in the area.
Insofar as transit relief can be considered indicative of the
success in spreading the peak, it should be noted that many work stag-
gering studies, both a priori and ex post facto, have concluded that
subway congestion in New York could be substantially relieved.
In th e
Lower Manhattan Anniversary Study, for example, it was determined that
passenger counts at the three busiest subway stations in lower Manhattan,
1. Chester Roy Julian, "Staggering Work Hours to Ease Existing Street
Capacity Problems," a paper prepared for 1971 World Traffic Engineering
Conference; Montreal, Canada (September 1971), p. 38.
2. Downtown-Lower Manhattan Association and the Port of New York Authority,
"Staggered Work Hours in Lower Manhattan, First Anniversary Report,"
April 1971.
3. Work hour staggering for mass transit (particularly subway) conges-
tion relief was studied in New York since over three-quarters of people
entering the Manhattan CBD on ~ typical business day between 7:00 and
10:00 a.m. use subways and buses. In this connection, since fewer vehicles
are needed to service a more uniform demand level, work hour staggering
could conceivably improve mass transit service and ridership levels by
increasing schedule frequency and serving additional routes.
-------
7 -8
showed a traffic decline of approximately 6 percent in the peak ten
minutes on two lines.
Furthermore, peak hour congestion on the Port
Authority Trans-Hudson (PATH) was significantly reduced as a result of
the program.
For the PATH system, passenger counts during the evening
peak 15-minute period at the Hudson Terminal declined by some 1,000
(from 7,500 to 6,500), a reduction of about 15 percent.
Passenger en-
trances into the Hudson Terminal in the more lightly traveled 4:30 to
1
4:45 period rose by nearly 50 percent.
These observations are graph-
ica11y depicted in Figure 7-2, which clearly shows a spreading of the
p.m. peak hour under a work staggering program for an almost identical
volume of riders.
The effectiveness of a work hour staggering program is highly
dependent on the number of "controllable" employees who are (1) within
the study area; (2) travel during the peak period; and (3) work for an
identifiable number of major employers.
The last consideration is crucial
since the complexity in designing an effective staggered working hours
2
plan and the absence of comprehensive statistical records regarding
1. Downtown-Lower Manhattan Association and the Port of New York
Authority, "Staggered Work Hours in Lower Manhattan, First Anniversary
Report," April 1971, p. 2.
2. A work staggering program must typically take into account a number
of considerations, among which are (1) the number of employers and
employees effected; (2) the extent of work schedule changes; (3) the
spatial distribution of trip origins and destinations; and (4) the
differential effects on morning and afternoon peaks. Usually, these
complex considerations can be evaluated only for a small set of employers
and employees, unless resources are available and sophisticated com-
puter simulation use~. In this regard, the Atlanta Staggered Hours
Study, after detailed investigation, chose only four major employers
(employing some 11,000 people) for suggested participation in the
program. Nevertheless, the study projected "significant" congestion
(Continued on page 7-10)
-------
7-9
Figure 7-2
EFFECTS OF STAGGERED WORK HOURS
ON P.M. PASSENGER VOLUMES
AT PATH HUDSON TERMINAL
0,000
February
---_October
1970 - 23,691
1970 - 23,786
2,000
-------
7-10
employer characteristics typically require that the number of employers
participating in the program be small.
These considerations also imply
that for those cities in which the proportion of peak travel attribu-
table to the journey to work is relatively low (e.g., Los Angeles,
San Francisco), the number of "controllable" employees is correspondingly
low, and may not allow design of an effective work staggering program.
At the heart of designing a staggered hours plan (and estimating
the air pollution control potential) are problems of forecasting traffic
volumes at various intervals of the peak period.
Paramount among the
difficulties is that work hour schedules only tell when employees are
reQuired to be at work, not when they actually arrive.
There is con-
siderable evidence in many cities that informal staggering occurs as
employees tend to start for work earlier and leave later in an attempt
to avoid peak congestion.
The combined effects of schedule change and
relief of congestion on heavily traveled routes can, and probably will,
bring about a change in this practice both by the people whose schedules
are changed and by the others who will also benefit from improved street
conditions.
The extent of such changes, however, cannot be easily
estimated.
Potential changes in behavior make it exceedingly difficult
to conclude definitively whether any given work staggering plan will
relieve congestion, and if so, to what degree.
An additional problem is that the relieved congestion will pro-
bably encourage some increased motor vehicle use for wcrk trips.
With
(continued from page 7-17)
relief -- estimating that a reduction in travel time of 10 minutes per
motorist per work hour could be saved. On a lS-minute increment basis,
it was estimated that the plan would reduce peak traffic volumes at the
cordon about S percent in the morning peak and almost 6 percent in the
afternoon peak. See Wilbur Smith and Associates, Staggered Hours Plan,
Atlanta Metropolitan Area, prepared for the State Highway Department of
Georgia et al. (Columbia, South Carolina: Wilbur Smith and Associates,
1970). -
-------
7-11
improved travel conditions resulting from staggering, some people now
using other modes (subways, buses, taxis) ~y shift to commuting by
private passenger car.
Compounding the problem even further is the
possibility that staggering may also dictate a different temporal dis-
tribution of non-work trips.
Finally, there is the unknown degree to
which work staggering would disrupt car pools.
Certainly, rearrangements
in work schedules will result in some portion of car pools being dis-
banded.
One study shows that approximately 58 percent of carpoo1ers
in Atlanta said that they would beg~h to drive alone if this occurred
(17 percent said they would take transit and 25 percent were undecided).l
To conclude, work staggering could conceivably contribute to
relieving peak hour congestion (and reducing motor vehicle emissions,
both by increasing average vehicle speeds and by distributing emissions
more evenly over time).
However, definite conclusions are difficult
to draw at this time about the precise impact of work staggering in
relieving congestion and resulting emissions more evenly over time.
1. See Wilbur Smith and Associates, Staggered Hours Plan, Atlanta Metro-
politan Area, prepared for the State Highway Department of Gerogia et al.
(Columbia., South Carolina: Wilbur Smith and Associates, 1970).
-------
7-12
The 4-Day Work Week
A great variety
of 4-day work week arrangements are possible.
Depending on the arrangement used (or more precisely the combination
of arrangements in any metropolitan area), transportation and air pollu-
tion impacts can vary considerably.
The most common 4-day work week
schedule is one in which the firm remains in operation five days a
week with only four-fifths of the employees present on a given day.
Alternatively, if one-half the employees work Monday through Thursday,
and the other half Tuesday through Friday, the entire reductions in
journey to work travel would occur on Monday and Friday, when only 50
percent of employees would be reporting for work.3
Table 7-2
summarizes
1. Journey to work trips in a motor vehicle account for slightly less
than 30 percent of total motor vehicle trips in the Los Angeles region,
26 percent in the San Francisco area and 15 percent in the Tri State
(greater New York) region.
2. Since less than 1 percent of the labor force is currently on a 4-day
work schedule, the assumption that one quarter of employees could be
converted within 5 years appears highly optimistic. It is highly unlike.
ly that more than a quarter of the labor force will be on the 4-day week
in the next five years.
3. R~ductions in work trips would be realized only if the "extra" day
were used for leisure or other non-work purposes. However, it is
conceivable that some proportion of the labor force would use the fifth
day for "overtime" or part-time employment. The prevalence of such
activity will determine the extent to which the actual reduction in
journey to work travel approaches the 20 percent (i.e., two less work
trips per week) reduction possibility.
-------
7-13
a number of possible 4-day working arrangements and indicates the per-
centage of employees who would be reporting for work on each of the days
of the week under the particular arrangement.
Table 7-2
POSSIBLE ARRANGEMENTS OF A 4-DAY WORK WEEK
4~Day Employee Weekly Percent of Employees on 4-Day
Work Schedule Working a Given Day
M Tu W Th F S
1. Equally rotated M-F 80 80 80 80 80
2. 1/2 M-Th; 1/2 Tu-F 50 100 100 100 50
3. Equally rotated M-Sa. 67 67 67 67 67 67
4. 1/3 M-Th; 1/3 Tu-F; 1/3 ~l-Sa 33 67 100 100 67 33
5. 1/2 M-Th; 1/2 W-Sa 50 50 100 100 50 50
Source: Vincent R. DesimonE:, "The 4 Day Work .week and Transportation",
A paper presented to the Joint ASCE ASME Transportation Engineering
Meeting, Seattle, Washington; July 1971, p.9.
As Table 7-2 indicates, the 4-day week has the potential for
affording significant peak hours congestion relief, at least on some
working days.
The degree of refief on a given day, of course, varies
with the percent of employees working.
As the percent diminishes, there
will almost always be a reduction in the number of quarter-hour periods
where roadway demand exceeds capacity.
-------
7-14
In an attempt to quantify these reductions, a recent study was
made of the impact of the 4-day week on Los Angeles freeway travel during
the peak periods.
The findings of this study concerning daily and
weekly transportation impact are summarized in Tables 7-3 and 7-4.
Table 7-3
1
DAILY IMPACT OF 4-DAY WORK WEEK ON CONDITIONS
AT A FREEWAY BOTTLENECK
Percent of
4-Day Employees
Working
Number of 15
Minute Periods
Demand Exceeds
Capacity
Excess Demand
Over Capacity
(Vehicles)
Reduction from 2
Current Conditions
(%)
80
8 1,181 33
3 577 69
2 414 77
2 234 87
1 69 99
100
67
50
33
Source: Adapted from Vincent R. Desimone, "The 4-Day Work Week and
Transportation", A paper presented to the Joint ASCE-ASME Transporta-
tion Engineering Meeting, Seattle, Washington; July 1971, p.13.
Note:
Data assume 35% of the work force is on the 4-day work week.
1.
Los Angeles' Hollywood Freeway at Highland Avenue.
2. Under the current 5-day work schedule, the number of 15 minute
periods demand exceeds capacity is 12 and the number of vehicles excess
demand over capacity is 1815 for a given day.
-------
7-15
Table 7-4
WEEKLY IMPACT OF 4-DAY WORK WEEK ON CONDITIONS1
AT A FREEWAY BOTTLENECK
Weekly Work Schedule 15 Minute Excess Reduction
Percent Working on Periods Demand From
Day Shown Demand ,I..,,,';:,~:~? ,-,. Over Current
Exceed~ Capacity Conditions2
Capacity - (Vehicles) (%)
M T W T F S
--~ - > On'
1. 80 80 80 80 80 0 15 2885 68
2. 50 100 100 100 50 0 28 4011 56
3. 67 67 67 67 67 67 12 2484 73
4. 33 67 100 100 67 33 22 3328 63
5. 50 50 100 100 50 50 24 3298 64
Source: Adapted from Vincent R. Desimone, "The 4-Day Work ~eek amd
Transportation", A paper presented to the Joint ASCE ASME Transportation
Engineering Meeting, Seattle, Washington, July 1971, p.13.
Note:
Data assume 35 percent of the work force is on the 4-day work week.
1.
Los Angeles' Hollywood Freeway at Highland Avenue.
2. Under the current 5-day work schedule the number of IS-minute
periods demand exceeds capacity is 60 and the number of vehicles excess
demand over capacity is 9075 for an entire week.
Table 7-3 shows that reductions in demand over capacity can
range from a low of 33 percent at 100 percent of 4-day employees work-
ing to 99 percent at 33 percent of 4-day employees working.
It is
interesting to note that at 100 percent of 4-day employees working, the
one-third reduction over current conditions occ~rs even though the
-------
7-16
same number of vehicles are traveling during a day.
The reason for this
is a spreading of the peak which occurs because 4-day employees generally
start work earlier than those on the 5-day week, an effect indentical
to the staggering of work hours.
As Table 7-4 indicates, the particu-
~ar 4-day work schedule ~mployed can have significant impact on reducing
the excess of demand over capacity -- varying from 73 percent reduction
under schedule 3 (i.e., and equally rotated 6-day schedule) to 56 percent
under schedule 2
(i.e. ,
one half working Monday through Thursday and
one half Tuesday through Friday). .Perhaps the clearest way of summar-
'''< ,- ~
izing this ~nformation and illustrating the potential of the 4-day week
to more effectively utilize existing roadway capacity would be to plot
daily roadway demand under various levels of 4-day employees reporting
for work versus time.
This graph is depicted in Figure 7-2.
Figure 7-3 indicates the potential of a 4-day week to alleviate
the frequencyl and duration of congestion during peak hours.
The extent
to which this potential can be realized (and air quality improvements
result) depends upon a host of factors (e.g., diversion out of mass
transit and car-pools to the automobile because of improved travel
times, increased overlap of non-work trips during the peak hours, and
1.
That is, the number of times that demand exceeds capacity.
-------
2220
2000
1800
1600
1400
1200
1000
7-17
Figure 7-3
DAILY DEMAND ON L.A. FREEWAY SYSTEM OVER TIME1
UNDER SEVERAL 4-DAY WORK WEEK SCHEDULES
800
600
:"f""~ I
Current Demand
~, ."
~~-,
i I/::'~ '
,
'\~".,.
j II I~.""', ~~ . ~,,"/~~ 'f, ".,,,.. .r, '!"I":----
- Capaci ty -- ---/: I -~'" ':M::,";'--- ------ >-.----
-- ~ I"
Uhi/ ~. - ,, 100\ "
1. Q!U... -~ ....... ~ 80a "
,... ",
1// ~n< /i:/j .........67% ,
, r';;;-~- '-:1 /~ " 50~ ~ "'- "
33% ....~
/ I!r ~c.:~, r:1 \
,-:.. "
\" -- Percent of 4-Day Employees -
.. II! rj~
Working a Given Day
@) -- --
0'-
/. "
"
400
200
5:00
5:30
10:00
6:00
6:30
7:00
7:30
8:00
8:30
9:00
9:30
TIME
1.
Los Angeles' Hollywood Freeway at Highland Avenue.
Source: Adapted from Vincent R. Desimone, "The 4-Day Work Week and
portation," a paper presented to the Joint ASCE-ASME Tr~nsportation
ing Meeting, Seattle, Washington, July 1971, p. 14. Data assume 35
of ~he work force is on the 4-day work week.
Trans-
E;ngineer-
percent
-------
7-18
1
80 forth).
Hence, it is not possible to est~ate with certainty emis-
sion reductions which wou1q result.2
~f the 4-day week is to be an effective short-term control, a
"substantial" portion of the labor force in any .netropoli tan area would
have to be converted to new schedules within five years.
"Substanti,,!-l,"
however, need not imply that in order to effect important emission re-
ductions, the proportion of the work force on the 4-day week must
approach 100 percent.
In fact, constructing a table similar to Table
7-4
but with 100 percent of all employees on the 4-day week, indicates
that mobiLity is actually better if 35 percent of all employees are on
3
the 4-day week than if 100 percent are.
This is due to the spreading
1. Over a longer period, several other considerations should be weighed
in evaluating the air pollution control potential of the 4-day week.
Most significantly, it is likely that decreased travel time will encourage
~uto commuters to live even farther from work, thus increasing dispersion.
Further, commuting fewer days could conceivably increase the tolerance
for driving with a resultant reduction in mass transit ridership (although
it is also possible that longer days would lessen tolerable levels
for driving in congested areas).
2. The distinction between reductions in peak hour travel and reduction
in total travel should be noted. Although the 4-day week appears to have
significant potential to reduce peak hour travel, it probably will not
reduce total travel and may actually increase it. There is no doubt
that ad~nal motor vehicle travel would be generated during the longer
contiguous periods of non-work afforded by the 4-day week. However, most
of this travel will be for pleasure or vacation, visiting relatives, "
and so forth. Consequently, such travel is likely to be during predomi-
nantly non-peak hours. What is more, the travel may well occur primarily
outside the CBD, in large measure, on rural and recreational roads.
Thus, from the standpoint of air pollution control, the shift in time,
place, and purpose of travel resulting from the 4-day work week appears
beneficial, even if total travel increases somewhat.
3. Vincent R. Desimone, "The 4-Day Work Week and Transportation." A
paper presented to the Joint ASCE-ASME Transportation Engineering Meeting,
Seattle, WashingtQn; July 1971, p. 17.
-------
7-19
of the peak that occurs when portions of the labor force have different
hours than others.
As will be indicated, however (see "Institutional Feasibility1'),
the number of firms having converted to the 4-day work week at this time
is small.
However, the rate of conversions has increased substantially
in the past year.
Thus, although one source has projected 1990 as the
earliest time 35 percent of the labor force would be on the 4-day week,l
this estimate may be unduly low in light of the accelerating rate of con-
. 2
verSl.on.
Maximum Feasible Emission Reduction
For reasons indicated earlier, the 4-day work week holds out more
promise for reducing emissions than any work staggering program.
As Table 7-4 indicates, several 4-day work arrangements are possible,
each associated with a different percentage of employees reporting for
work on a particular day.
Thus, although the total weekly vehicle miles
traveled for the journey to work would be reduced by 20 percent, daily
reduction can vary from no reductions at all to 67 percent.
Since the
focus
of this project is on reducing average 8-hour carbon monoxide
1. William W. Nash, Jr., Implications for Urban America, cited in
Vincent R. Desimone, "The 4-Day Work Week and Transportation," A paper
presented to the Joint ASCE-ASME Transportation Engineering Meeting,
Seattle, Washington; July 1971, p. 7.
2. In discussing the rate of conversions to the 4-day week, it should
be borne in mind that the complete transition to the present 5-day week
(from six) took place in about 20 years. In 1918, there were only a
few 5-day firms; some 11 years later only 5 percent of the labor force
was on 5-day; and by 1940 the 5-day week was the established norm.
It should also be noted that
has shifted a number of holidays
4-day weeks in 1971, which means
made up of 4-day weeks.
recently effective federal legislation
to Monday. This has resulted in ten
about one-fifth of the year is already
-------
7-20
concentrations, it is the daily reduction in vehicle miles traveled that is
significant, rather than weekly totals.
Accordingly, 4-day work arrangements that result in no reduction
in the percentage of employees reporting for work on any weekday are less
acceptable for air pollution control purposes (even if considerable re-
ductions occur on all other days of the week) than equally rotated 4-day
work schedules (see Table 7-4).
With an equally rotated Monday to Friday
arrangement, work trips (of the 4-day labor force) on each day would be
reduced by 20 percent, while an equally rotated Monday to Saturday arrange-
ment would result in a daily reduction of work trips by 33 percent.
On
this basis it can be concluded that an equally rotated Monday to Saturday
schedule (i.e., the 4-day week spread over six days) is the arrangement
which would result in the most emission reductions.
Since only a third of the 4-day week labor force does not report for
work on any working day under this arrangement, the reductions in vehicle
1
miles traveled (and hence emissions attributable to reduced travel) can
be readily calculated.
Assuming that approximately 30 percent of vehicle
. 2 d
miles traveled are attributable to work tr~ps, an that a maximum of 25
percent of the labor force would be on the 4-day week by 1977,3 the maxi-
mum daily reductions in vehicle miles traveled from the 4-day work week
can be estimated at 2.5 percent (.33 x .30 x .25).
1. In addition to reduced travel, emission reductions would probably
result from improved flows. Calculation of these "additive" effects,
however, cannot be carried out without computer simulation and extensive
analysis of demand and capacity relationship on a city-by-city basis.
For several illustrative examples of these relationships, see Appendix C.
2. Journey-to-work trips in motor vehicles account for slightly less
than 30 percent of total motor vehicles trips in the Los Angeles region,
26 percent in the San Francisco area and 15 percent in the Tri-State
(greater New York) region.
3. Since less than 1 percent of the labor force is
work schedule, the assumption that this figure will
within five years would appear highly optimistic.
currently on a 4-day
increase to 25 percent
-------
7-21
Institutional Feasibility
As earlier indicated ("Definition of Terms"), work schedule change
possibilities may be grouped into two categories, "Work Staggering" and
"The 4-day Week."
Most variants of work staggering entail relatively minor
modifications in economic activity, travel patterns, and overall life styles.
The 4-day work week, on the other hand, implies a profound alteration in
productivity, work, habits, recreational patterns, leisure time, and so
forth.
These profound implications of any large shift to the 4-day working
week would seem to preclude the possibility of its being introduced merely
to reduce motor vehicle congestion and emissions.
Any evaluation of the
feasibility (and desirability of the 4-day work week) should consider this
wide range of impacts; and the air pollution control potential of such a
. . b. 1 d 1
policy, of course, should be borne in mind as ~t ~s e~ng eva uate .
It
should be noted, nevertheless, that the 4-day work week appears to be gain-
ing popularity in the United States (although at present only a small frac-
tion of the labor force works under this schedule).2
We confine the following, therefore, to a discussion of work stag-
gering.
It should be borne in mind that considerations of feasibility vary
1. Attention should also be paid to the safety aspects of the 4-day week.
Present patterns indicate that the 4-day week has a high potential for in-
creasing accidents and accident rates. Current injury accident rates are
about 30 percent higher on week-ends than on weekdays with rates on 3-day
weekends about the same as 2-day weekends. A mid-week holiday, on the other
hand, seems to produce about an 80 percent increase over the weekday rates.
2. Growing interest in the 4-day work week is reflected in a recently
initiated newsletter on the subject. According to a recent issue, th~ rate
of conversion to reduced work weeks, reported in mid-1970 to be two firms
a day, had doubled in less than a year. Poor's Workweek Letter, (Cambridge,
Mass.: September 1, 1971), p. 1.
-------
7-22
somewhat from city to city depending on factors including the location and
kinds of employment centers, location and kinds of employment, residential
patterns, the existing transportation system (e.g., roadways, rapid rail
lines) and so forth.
Staggering Work Hours
Work hour staggering is by no means new, having been initiated in
1
cities both in the United States and abroad as early as the 1920's.
At
the present time there are two recently initiated work-hour staggering pro-
jects in existence: in the lower Manhattan area of New York City and in
Washington, D.C.
In addition, a work hour staggering study has been recent-
1y completed for the City of At1anta.2
In order for work staggering to be feasible, sufficient3 unused
roadway capacity must exist before and/or after peak traffic periods.
If
demand already exceeds capacity over relatively long periods, little relief
of roadway congestion can result from staggering work hours.
However,
since capacity in and around the CBD's of most cities is generally expanded
1. During World War II, considerable attention was focused on work stagger-
ing and actual plans were implemented in some 60 American cities to alleviate
transportation problems. (The most extensive experience with work-hour stagger-
ing has occurred in Washington, D.C. where a program was introduced in World
War II and again in the 1960's.) Unfortunately, however, there was virtually
no evaluation of these World War II experiences (all of which were terminated
after the war). As one comprehensive study of work-hour staggering points
out about the World War II work staggering experience, "Perhaps its most per-
sistent theme is the absence of a record of results." Lawr~nce B. Cohen, Work
Sta~~erin~ for Traffic Relief: An Analysis of Manhattan's Central Busines~
District (New York: Praeger, 1968) p. 6. .
2. Wilbur Smith and Associates, Staggered Hours Plan Atlanta Metropolitan
Area (Columbia, South Carolina: 1970.
3. That is, sufficient to accommodate large enough portions of peak traffic
to produce a significant improvement in traffic conditions.
-------
7-23
with the goal of adequately meeting peak hour demand, "sufficient" unused
or available capacity exists in most cities before and after the peak.
Feasibility also implies that work staggering plans be clear and
simple, and hence readily comprehensible to all concerned.
P1am consist-
ing of separate and detailed schedules for individual firms would be exceed-
ing1y difficult to implement.
In addition, for most work hour staggering
programs to be feasible, participation must be on a voluntary basis, both
for the employer and the employee.
This does not mean that every individual
employee be free to accept or reject work staggering, but simply that co1-
1ective1y employees would voluntarily comply.
As one comprehensive work
staggering study states:
This stricture of a voluntary program is
simply a recognition of social reality.
is no way by which work staggering could
imposed upon the community...
in one sense
There simply
be forcefully
Above all, for work staggering to be feasible -- indeed to occur at
all -- work schedules must be subject to modification.
Employers and em-
ployees in other words, must be able to accommodate work schedule changes.
Most employers, for example, will wish to consider the impact of work
schedule changes on the economic viability of their enterprise, while em-
ployees will consider the potential of modified work schedules to disrupt
their daily patterns.
Feasibility for employers.
The need to maintain specified work
schedules differs from firm to firm.
If a firm's schedule differs from
that of its suppliers and/or customers, economic activity is precluded
1. Lawrence B. Cohen, Work Staggering for Traffic Relief: An Analysis of
Manhattan's Central Business District (New York: Praeger, 1968), p. 9.
-------
7-24
during portions of the day.
Depending on how essential are these activities,
schedule changes (whether of the firm, its suppliers, or customers) may cause
losses in sales, failure to receive or deliver merchandise, supplies or ser-
vices,
and so forth.
Schedule changes could also cause inefficiencies within
a given firm.
Detailed industry studies conducted for the Manhattan and Atlanta
CBD's provide many insights into these economic interrelationships and the
potential impact of work-hour scheduling on efficient conduct of business. 1
Based on observations of industry-wide business practices it was possible
to determine which industries had work schedules which were most subject to
modification.
Furthermore, it was found that the extent to which modifica-
tions were possible could be detailed for specific industry classifications.
In general, trade oriented firms (i.e., firms such as retail shoes or whole-
sale establishments that must adjust their hours to customer flow and must
be located where and when customers are present) were found to have schedules
which must conform to those of others.
Such firms could only shift if their
customers shift.
Other firms were found which had to adapt their working hours to
industry requirements or outside factors (e.g., flow of materials, arrival
of intercity carriers) or the hours observed by the home office in another
city (e.g., stock brokerage firms, firms accessing a central computer).
In
general, such firms have relatively fixed working hours.
Transportation,
1. Industry surveys and sociological analyses for Manhattan were conducted
as part of comprehensive research on work hour staggering. These studies
were independently released but are adequately summarized in the previously
noted work. Lawrence B. Cohen, Work Staggering for Traffic Relief: An
Analysis of Manhattan's Central Business District, (New York: Praeger, 1968),
Chapters 4 and 5.
-------
7-25
communication, and utilities, since they cater to customers as well as out-
of-town affiliates, are examples of industries falling in this classification.
A considerable number of firms, not bound by customer flow or other
external factors, have great latitude in scheduling working hours.
These
firms, of course, form the target in the design of a staggered hours program.
Organizations primarily adm~nistrative in nature -- especially governmental
agencies -- mainly comprise this category.
Table 7-5 summarizes the schedule
freedom and, thus, the staggered hours potential for a variety of employment
classifications in the Atlanta CBD.
Both the Manhattan and Atlanta studies concluded that latitude for
schedule change varies among firms and industries, but that the notion of
all firms or industries having fixed schedules and not being able to con-
duct their operations otherwise could not be supported.
Feasibility for employees.
As indicated above, work staggering must
also be acceptable to the employees (and others) involved.
Quite obviously
changes in work schedule may have significant repercussions in well-
established social and cultural patterns to which employees have become
accustomed.
Work schedule changes may entail modifications in departure
times to and from work, the portions of the day spent home, and the hours
spent in social, recreational or other activities.
These changes, in turn,
could affect employee's families, friends, and associates as well as the
schedules of the businesses, services, and institutions with which they
deal.
Given these potential consequences from changing work hour schedules,
the extent to which work schedule changes are sufficiently acceptable for
those affected must be determined.
-------
7-26
Table 7-5
SUMMARY OF SCHEDULE FREEDOM AND STAGGERED HOURS
POTENTIAL BY EMPLOYMENT CLASSIFICATION
Employment
Classification
Schedule
Freedom
Staggered Hours
Potentj "11
Federal Government
Freel
Good; many small
agencies
State Government
Free
Good
Local Government
Free
Good
Trans-Comm-Util.
2
Fixed
Poor; transporta.
tion (trade
oriented)
Education Fixed
Service Free
3
Retail Flexible
Manufacturing Free
Wholesale Flexible
Poor
Good; banks
(trade oriented)
Fair; large
firms only
Fair +
Poor
30urce: Adapted from Wilbur Smith and Associates, "Staggered Hours Plan,
Atlanta Metropolitan Area," 1970, p. 31
1. "Free" indicates organizations with considerable latitude to
hour schedules. In theory, schedules could encompass any period
if it were not for employee preferences. Shifts of at least one
hours appear possible.
set work
in the day
to two
2. "Fixed" indicates organizations with no flexibility to change work
patterns to any schedule other than existing ones.
3. "Flexible" indicates organizations which could potentially alter work
hour schedules, but only if related firms (i.e., firms in the industry,
customers, suppliers, and so forth) do the same. Since such shift~ from
established economic relationships usually involve a great number of firms
and business practices, the extent of schedule change acceptable to such
organizations is probably one hour or less.
-------
7-27
Seeking to resolve this issue, a team of sociologists conducted a
large-scale survey of employee attitudes toward work staggering in the
Manhattan CBD.
Among other things, employees were asked when they would
prefer to start and stop work (assuming they had free choice and the same
number of working hours were required as the present).
The survey results
are shown in Table 7-6.
Table 7-6
PERCENTS OF SAMPLE PREFERRING CHANGED
STARTING TIMES, BY MINUTES OF CHANGEl
Minutes of Change Percent Earlier Percent Later
15. - 29 10 6
30 - 59 21 9
60 or more 12 6
Total 43 21
Source: Lawrence B. Cohen, Work Staggering for Traffic Relief: An Analysis
of Manhattan's Central Business District (New York: Praeger, 1966), p. 190
As indicated, only 37 percent stated a preference for present
starting times, with some 64 percent (rounding discrepancies) preferring
times other than those they now have.
This result may seem surprising
since most employees appear satisfied with their present schedules, at
least judging from the absence of union (or other employee) pressure in
-------
7-28
this regard.
In an attempt to explain this finding, the authors of the
Manhattan work staggering study conclude:
. . . while most respondents reported being satisfied
with their work times, . . . most also preferred dif-
ferent work times. The reason is now clear: work
times compared with other aspects of a job or with other
times in a person's schedule are just not very important
to the respondents. They are not psychologically salient
elements nor are they something that most people care
very deeply about. Hence they are 'satisfied' with them
-- whI not? -- but at the same time they prefer other
ones.
In addition to preference, the Manhattan study sought to determine
the "tolerance level" of employees to schedule change.
Tolerance was
defined as the extent of change respondents were willing "to go along
with behavior1y", i.e., the boundary of non-resistance.
As might be
expected, the results indicate that people tolerate far more change than
they prefer:
an earlier starting time would be preferred by 43 percent
of the people, while 93 percent will tolerate an earlier starting time.
A later starting time would be preferred by 21 percent of the people,
and tolerated by 86 percent.
On the basis of this, and other evidence,
the study concluded that "there are some who object to schedule change,
but they are too few and too scattered to be considered a source of ef-
fective resistance."
The finding of this a priori study that work hour staggering would
be feasible -- both for employers and employees -- appear confirmed by the
experience of two on-going work-hour staggering projects.
In the lower
Manhattan project, sponsored by the Port of New York Authority and the
1. Lawrence B. Cohen, Work Staggering for Traffic Relief: An Analysis
of Manhattan's Central Business District (New York: Praeger, 1968), p. 191.
-------
7-29
Downtown-Lower Manhattan Association, approximately 50,000 persons em-
ployed by 45 firms and government agencies in lower Manhattan began shift-
ing work hours (principally off the 9-5 schedule to 8:30 AM to 4:30 PM) in
April 1970.
As of one year later, there were about 60,000 perople representing
70 private firms and government agencies on the new schedule.
The results
of a recently released evaluation of this project indicate conclusively
that both regular employees and their supervisors viewed their personal
experiences in positive terms under staggered work hours contributed to
enhanced efficiency in their organizations.
In brief, some of the most significant findings of the Lower Man-
hattan Association hour staggering program were: (1) almost 85 percent of
the participants were more satisfied with commuting under the staggered
schedule, while only 10 percent were less satisfied; (3) almost all project
participants highly favored the project in terms of its effects on home
life, their evening activities, and so forth; and (4) more than 21 percent
of the participants reported increased work effectiveness (while only 4
percent reported a decrease in work effectiveness).
The report containing
these findings concluded:
from the enthusiastic reactions of the participants
in both government and industry, . . . the project
~an be termed an unqualified success. We learned,
in the first year, that thousands of men and women
who work in lower Manhattan are quite willing to
change their work schedule in order to make traveling
more comfortable. We learned further that the shift
did not have a detrimental effect on the operations
or efficiency of the firms participating; indeed, in
most cases, the effects on efficiency were positive.
These were the two key questions the porject sponsors 1
set out to research. They have been answered affirmatively.
1. Downtown-Lower Manhattan Association
Staggered Work Hours in Lower Manhattan,
1971, p. 2.
and the Port of New York Authority,
First Anniversary Report, April
-------
7-30
Recent (1969-1970) experiences with staggering in the Washington,
D.C., metropolitan area have also indicated the feasibility of work hour
staggering.
In the most recent exp~rience, a staggered work hour plan was
implemented for 24 federal agencies employing over 18,000 employees in
Crystal City, Virginia.
The schedule shifts -- which started work earlier
in amounts up to one hour -- engendered only "minor and informal com-
plaints" according to a follow-up study. 1
1. C11ester Roy Julian, "Staggering Work Hours to Ease Existing Street
Capacity Problems," a paper prepared for the 1970 World Traffic Engineering
Conference; Montreal, Canada (September 1971), p. 38. The possibility of
employer resistance did not arise for federal agencies in the Washington
area as it might for private sector employers elsewhere.
-------
APPENDICES
-------
A P PEN D I X A
ESTIMATING EMISSION REDUCTIONS FROM RETROFIT 1
Estimating the emission reductions from retrofit requires considera-
tion of:
(1) the contribution of pre-controlled vehicles to aggregate
(i.e., light duty motor) vehicle miles traveled (taking into account that
pre controlled vehicles are fewer in number but tend to be driven less than
newer ones); and (2) the emissions from an average pre-controlled vehicle
compared with those from a controlled vehicle.
With these data, the aggre-
gate emission reduction following retrofit installation can be computed by
multiplying the expected per vehicle emission reduction following retrofit
installation by the ratio of pre-controlled automobile emissions to total
automobile emissions in a given year.
The basic working equation is as
fo !lows:
Percent ini tia 1
reduction in ag-
gregate emissions
due to retrofit
installation in
year N
=
Maximum expected emis-
sion reduction for aver-
age pre-controlled vehi-
cle fitted with retrofit
device (estimated in th~
report to be 25 percent)
Total emissions
from pre-controlled
automobiles in
year N
Total emissions
from all auto-
mobiles in year N
1. All estimates are for initial reductions, and do not take into account
deterioration of retrofit devices due to accumulation of mileage. By
"emissions" we refer to carbon monoxide; by "aggregate" emissions (or emission
reductions) we mean the carbon monoxide attributable to light duty motor
vehicles in any given area. Thus, to the extent that emissions are attrib--
utable to heavy duty vehicles (e.g., buses, trucks) or to stationary sources
(e.g., space heating), reductions in overall emissions (i.e., carbon monoxide
from all sources in a given area) will be less than estimated here.
-------
A-2
Expressing the above equation symbolically. we have
(1)
~ EN
=
R
M
L
i=N-12
(VMT. x EF.)
~ ~
x
N
L
i=N-12
(VMTi x EFi)
Note: The subscript "N-12" reflects the fact that, based on existing
trends, the preponderance (over 97%) of vehicle miles traveled will be
generated in year N (1975 or 1977) by vehicles 12 years old or newer.
to EN
is the initial reduction in emissions following retrofit installa-
tion in year N, expressed as a percentage of aggregate emissions;
R
is the maximum expected emission reduction for an average pre-
controlled vehicle fitted with retrofit device (estimated in
this report to be 25 percent);
M
is the last pre-controlled model year (1965 for California vehicles,
1967 for all others);
VMI"
~
is the total annual vehicles miles traveled by vehicles of model
year i;
EFi
is the average per-mile emission factor for vehicles of model
yea r 1.
The potential aggregate emission reduction from retrofit instal-
lation can be projected for any future year by inserting the appropriate
vehicle miles traveled and emission data as indicated above.
For example,
the aggregate emission reduction in 1975 resulting from retrofit instal-
lation on pre-controlled vehicles in California can be calculated on the
-------
A-3
basis of the data shown in the table below.
In this table, VMT values are
expressed relative to the base year (in this case 1975) and do not corres-
pond to any particular model year.
EF values, in contrast, relate to the
particular model year.
Model Year i 1/ EF.l/
VMT.-
1. 1.
1975 16% 55 g/mile
1974 14 61
1973 12 66
1972 10 71
1971 9 78
1970 8 84
1969 8 91
1968 7 96
1967 5 101
1966 4 106
1965 3 112
1964 2 112
1963 3 112
1. T. A. Bostich and H. J. Greehalgh, "Relationship of Passenger Car Age
and Other Factors to Miles Driven"" (Washington, D.C.: U. S. Department
of Commerce, Bureau of Public Roads, January 1967), as cited in H. W.
Sigworth, Jr., "Estimates of Motor Vehicle Emission Rates" (unpublished
paper prepared for the U.S. Environmental Protection Agency, Washington,
D.C., March 15, 1971), p. 14.
2. H. W. Sigworth, Jr., "Estimates of Motor Vehicle Emission Rates" (un-
published paper prepared for the U.S. Environmental Protection Agency,
Washington, D.C" March 15, 1971), p. 13.
The future per-mile emission factors are, of course, speculative. As
indicated elsewhere, there is some uncertainty also about actual on-the-
road emission factors for present in-use vehicles. The specific set of
factors used in ~he above analysis appear to be as representative as any
other. However, eve~ if the emission factors used for controlled vehicles
were lower by 10 or 15 percent (as some research has indicated), the effect
on potential aggregate emission reductions following retrofit would be
negligible. For example, in the calculations for California, reducing the
emission factors of controlled vehicles by 10 percent increases the aggre-
gate emission reduction potential of retrofit by less than 0.5 percent.
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A-4
Inserting these numbers into equation (1) above yields an expected ag-
gregate emission reduction of 2.9 percent in 1975:
(2)
I:. E1975 = .25
= .25
= 2.9%
(3xl12)+(2xl12)+(3xl12)
(3xl12)+(2xl12)+(3x112)
+(4xl06)+(5xlOl)+(7x96)+(8x91)+(8x84)
+(9x78)+(10x71)+(12x66)+(14x61)+(16x55)
[896J
l2835 J
= .02859
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A P PEN D I X B
ESTIMATING EMISSION REDUCTIONS FROM CONVERSION TO GASEOUS FUELS1
Conversion of New York City Medallion Taxicabs
For reasons indicated in Chapter 2, we have chosen New York City's
medallion taxis to illustrate the maximum feasible emission reduction from
conversion to gaseous fuels.
The calculations in this Appendix represent
control beyond that whiCh is expected to occur as a result of normal vehicle
2
turnover rates and full compliance with federal new car standards.
The
computations require consideration of (1) pre- and rost-conversion emis-
sion factors; (2) the emissions from medallion taxis in the area consid-
ered; and (3) the total and aggregate motor vehicle emissions in the spec i-
tied area.3
Basic data for these calculations are presented in Table B-1.
1. Unless otherwise indicated, the computations in this Appendix are
based on data from the New York Environmental Protection Administration
"Proposed Plan for Meeting Federal Air Quality Standards Relating to
Carbon Monoxide, Hydrocarbons, Nitrogen Oxides, and Oxidants in New York
City," New York, 1972. (Mimeographed draft.)
2. In addition, all estimates are for initial reductions and do not take
into account deterioration due to accumulation of mileage. By "emissions"
we refer to carbon monoxide; by "aggregate" we mean emissions or emission
reductions attributable to light duty motor vehicles; by "total" we refer
to emissions or emission reductions attributable to all motor vehicles
(i.e., both light and heavy duty). Finally, "overalli' emissions refer to
carbon monoxide from all mobile and stationary sources in any given area.
3. Motor vehicles account for 97 percent of carbon monoxide emissions in
New York City in 1970 and a projected 98 percent in 1975.
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B-2
Table B-1
BASIC NEW YORK CITY DATA FOR 19751
Carbon Monoxide Emission Factors
Manhattan Fleet Medallion Taxicabs
33.9 grams/mile
Manhattan Non-fleet Medallion Taxicabs
53.1 grams/mile
Percentage of Overall CO Emissions in New York City
Attributable to Mptor Vehicles
1970
97%
1975
98'70
Borough of Manhattan
Total CO Emissions from Motor Vehicles
221,471 tons/year
148,574 tons/year
14, 124 tons/year
8,100 tons/year
Aggregate CO Emissions from Light Duty Vehicles
CO Emissions from Fleet Medallion Taxicabs
CO Emissions from Non-Fleet Medallion Taxicabs
Midtown Manhattan Central Business District
Total CO Emissions from Motor Vehicles 56,771 tons/year
Aggregate CO Emissions from Light Duty Vehicles 26,170 tons/year
CO Emissions from Fleet Medallion Taxicabs 10,187 tons/year
CO Emissions from Non-Fleet Medallion Taxicabs 7,366 tons/year
Source: New York Environmental Protection Administration, "Proposed Plan
for Meeting Federal Air Quality Standards Relating to Carbon Monoxide,
Hydrocarbons, Nitrogen Oxides, and Oxidants in New York City," New York,
1972. (Himeographed draft.)
1. Full compliance with federal new car emission standards and normal
vehicle turnover rates are assumed.
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B-3
Emission Reduction for Fleet and Non-fleet Medallion Taxicab Populations
In order to demonstrate the sensitivity of overall emission reduction
projections to the estimated emission reduction for specific converted
taxicab populations, two different reported values will be used in this
analysis:
a 60 percent reduction in CO emissions from fleet and non-fleet
medallion taxicabs.l
,
and a carbon monoxide emission factor of 5 grams/mile
for all converted vehicles.2
The latter is equivalent to the following
emission reductions for specific taxicab populations in Manhattan:
Emission
reduction for
specific vehicle
population
overall emission
factor for specified
vehicle population,
g/mile
- (5.0 grams/mile)
=
x 100%
overall emission
factor for
vehicle population,
g/mile
Emission reduction for
fleet medallion vehicles
=
33.9 - 5.0
33.9
x 100 %
=
85.3%
Emission reduction for
non-fleet medallion vehicles
53.1 - 5.0
53.1
x 100%
90.6%
", .b: ~<..' \ ,~, 1 :,' .
1. New York Environmental Protection Administration, "Proposed Plan
for Meeting Federal Air Quality Standards Relating to Carbon Monoxide,
Hydrocarbons, Nitrogen Oxides, and Oxidants in New York City," New York,
1972, p. 4-27. (Mimeographed draft.)
Note: The New York City Implementation Plan considered conversion of fleet
medallion taxicabs only and therefore the 60 percent assumed reduction in
per vehicle carbon monDxide emissions is strictly applicable only to fleet
vehicles. However, du~ to lack of specific N.Y.C. data on emission reduc-
tions for non-fleet taxicabs, the 60 percent reduction is assumed to be
applicable to both fleet and non..fleet vehicles for the purposes of this
calculation.
2.
[see following page]
-------
B-4
Reduction in Total CO Emissions from Motor Vehicles
In order to determine the percent reduction in total motor vehicle
emissions, the emission
reduction achievable through conversion of medal-
lion taxicabs must be weighted by the relative contribution of these vehicles
to the total motor vehicle emissions in the geographical area under con-
'd . 1
s~ erat~on. The general relationship is:
AE =
Reduction in total
CO emissions from
motor vehicles
Emissions reductionJ Total CO emissions
for vehicle popula- from vehicle popula-
tion under considera- tion under considera-
tion, e.g., fleet or tion in the specified
non-fleet geographical area
ITotal CO emissions from alj
motor vehicles in the speci-
fied geographical area
x 100%
(continued from previous page)
2. Estimated on the basis of simple conversion involving the installation
of gaseous fuel system, pressure regulator, air-gas mixer, blocked manifold
heat, and some minor adjustments of engine variables -- such as a leaner
air fuel ratio, slightly retarded timing, increased idle speed, and dis-
connected vacuum advance. Source: Institute of Gas Technology, Emission
Reduction Using Gaseous Fuels for Vehicular Propulsion (Chicago: Institute
of Gas Technology, 1971), p. 3-11.
Note: This is basically an "initial" emission factor representing emissions
from newly converted vehicles and does not account for the possibility of
deterioration in control efficiency (i.e., an increasing emission factor
over time) with accumulated mileage. There appears to be no reliable data
on control efficiency deterioration for gaseous fuel vehicles.
1. In order to obtain aggregate (i.e., light duty motor vehicle) emission
reductions, the same procedure would be followed using aggregate emission
data from Table B-1.
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L
B-5
Borough of Manhattan
Conversion of all fleet and non-fleet medallion taxicabs in the
A.
1975 Manhattan taxi population -- effect on total carbon monoxide
emissions from all motor vehicles in the Borough of Manhattan.
1.
Assuming 85.3% reduction in CO emissions for converted fleet
fleet vehicles
vehicles and 90.6% reduction in CO emissions for converted non-
(i.e., using the 5.0 g/mile emission factor for
converted vehicles).
(0.853)
+ (0.906)
AE
=
Total CO emissions from motor vehicles in Manhattan, tons/year
co emissions from
non-fleet medallion
taxicabs in Manhattan
tons/year
=
(0.853) (14,124 tons/year) + (0.906) (8100 tons/year)
x 100%
221,471 tons/year
=
8.8%
2.
Assuming 60% reduction in CO emissions from converted fleet and
non-fleet vehicles.
(0.60) (14,124 tons/year + 8100 tons/year)
AE
221,471 tons/year
=
6.0%
x 100%
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B.
.toE
.toE
B-6
Conversion of all fleet medallion taxicabs in the 1975 Manhattan
taxi population -- effect on total carbon monoxide emissions from
motor vehicles in the Borough of Manhattan.
1.
Assuming 85.3% reduction in CO emissions for converted fleet
vehicles and 90.6% reduction in CO emissions for converted non-
fleet vehicles.
(0.853) (14,124 tons/year)
x 100%
221,471 tons/year
=
5.4%
2.
Assuming a 60% reduction in CO emissions for converted fleet
and non-fleet vehicles.
(0.60) (14,124)
=
x 100%
221,471
=
3.8%
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II.
B-7
Midtown Manhattan Central Business District
A.
Conversion of all fleet and non-fleet ~eQal1ion taxicabs in the
1975 Midtown Manhattan Central Business District taxi population --
effect on total carbon monoxide emission~ from all motor vehicles in
the Midtown Manhattan CBD.
1.
Assuming 85.3% reduction in CO em~~sions for converted fleet
vehicles and 90.6% reduction in CO emissions for converted non-
fleet vehicles
(5.0 g/mi1~ emissions factor for converted
vehicles) .
(0.853)
+
(0.906)
AE
CO emissions from
non-fleet medallion
taxicabs in Hicitown
CBD, tons/year
CO emissions from
fleet medallion
taxicabs in Midtown
CBD, tons/year
Total motor vehicle CO emissions in ~idtown CBD, tons/year
0.853 (10,187) + 0.906 (7,366)
x 100%
56,771
27.1%
2.
Assuming 60% reduction in CO emissions for converted fleet
and non-fleet vehicles.
0.60 (10,187 tons/year + 7,366 tons/year)
.6E
x 100%
=
56,771 tons /year
18.57.
-- x 10070
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B-8
B.
Conversion of all fleet medallion taxicabs in the 1975 Midtown
Manhattan Central Business District taxi population -- effect on
total motor vehicle emissions in the Midtown CBD.
1.
Assuming 85.3% reduction in CO emissions for converted fleet
vehicles and 90.6% reduction in CO emissions for converted non-
fleet vehicles.
0.853 (10,187 tons/year)
AE
x 100%
=
56,771 tons/year
=
15.3%
2.
Assuming 60% reduction in CO emissions for converted fleet
and non-fleet vehicles.
0.60 (10,187 tons/year)
AE
x 100%
=
56,771 tons/year
=
10.8%
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A P PEN D I X
C
SPEED-EMISSION RELATIONSHIPS
Many of the transportation controls considered in this report have
been advanced on the assumption that motor vehicle exhaust emissions (car-
bon monoxide) are lower in freely flowing traffic at high average vehicle
speeds than in congested stop-and-go conditions.
Careful consideration of
':
these measures, however, requires recognition of the numerous assumptions
1 'j}" ,. .-.;
and limitations inherent in speed-emission relationships.
Unfortunately,
basic research on these relationships has not been readily available.
Accor-
dingly, we are reproducing the key technical papers in this Appendix in
/'1 :
order to present the best available data and complete background informa~
tion.
Comparison of Auto Exhaust Emissions from Two Major Cities, Rose,
et
a1. (1964) is the definitive work on the effect of automobile speed on
- -
exhaust emissions.
In this study, on-the-road samples of exhaust from~
controlled automobiles indicated a consistent relationship of decreasing
hydrocarbcn and carbon monoxide emissions with increasing average route
speed (distance/time).
Nitrogen oxide emissions were found to be inde-
pendent of vehicle speed.
It should be emphasized that the speed-emission
relationships developed in this document are applicable only to automobiles
without exhaust control devices.
Project M-220, Effect of Speed on Emissions (1971), California Air
Resources Board, was based on an extremely limited sample of both pre-
controlled and controlled automobiles.
Exhaust emissions were monitored
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C-2
while the vehicles were exercised on a chassis dynamometer at specific
steady-state speeds and at average speeds represented by the California
7-~de procedure.
It is tmportant to note the distinction betWeen
steady-state speeds which do not include idle, acceleration, and decelera-
tion (Figures 1 through 4); and average speeds which represent actual driving
patterns including idle, acceleration, and deceleration sequences (Figure 5).
This difference is clearly illustrated in Figure 5.
The general trend of
decreasing hydrocarbon and carbon monoxide emissions with increasing average
speed was confirmed in this study (Figure 5).
Nitric oxide emissions were
found to increase with average speed (Figure 5a).
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C-3
Project M-220
EFFECT OF SPEED ON EMISSIONS
March 1971
California Air Resources Board
Air Resources Laboratory
434 South San Pedro Street
Los Angeles, California 90013
-------
C-4
Project M-220
EFFECT OF SPEED EMISSIONS
Introduction
The purpose of the tests covered in this report was to determine the
effects of vehicle speed on emissions.
Five vehicles were tested.
They included:
1971
1971
1970
19611
1971
(383 in3)
(318 in3)
(350 in3)
(283 in3)
(350 in3)
Chrysler
Dart
Chevrolet
Chevrolet
Pontiac
All vehicles were tested at a true speed of 20, 30, 40, 50, 60 and 70
miles per hour.
Test Procedure
1.
Each vehicle was run on the dynamometer at a steady speed for 2 to
5 minutes (until all readings were reasonably stabilized). Inertia
load was set corresponding to vehicle weight and road load was set
per 7-mode procedure.
2.
Consecutive runs were made at 20, 30, 40, 50, 60 and 70 miles per
hour. Road load which had been set at 50 miles per hour was
allowed to change with speed per the dynamometer curve (cube func-
tion).
3.
After conditions had stabilized at each speed, hydrocarbon, carbon
monoxide, and nitric oxide were recorded by chart readout of NDIR
instruments. Simultaneously the exhaust gas was collected in bags
for a timed period of 1 to 3 minutes depending on speed.
4.
After each run the exhaust was discharged from the bag and the flow
rate and time measured on a chart recorder.
5.
Calculations were made to obtain exhaust volume per mile and miles
travelled during exhaust gas collection. These values were used to
calculate the mass emissions on a grams/mile basis.
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C-5
Results
Results are shown in Figur~ 1 to 4. Fi2Ures 1. 2. and 3
show hydrocarbon, carbon monoxide, and n1tr1C oxide emissions re-
spectively ~or all the vehicles.
Figure
4 shows the overall average of all five vehicles.
Conclusions
As seen by Figure 4, hydrocarbon emissions changed very little,
dropping off slightly as speed is increased to 30 and 40 miles per
hour then increasing slightly as speed is further increased to 70
miles per hour.
Carbon monoxide averages drop about 40% as speed is increased to 30
miles per hour then increase to over twice the original value (at 20
mph) as speed is increased to 70 miles per hour. There is considerable
variation among the different cars probably related to differences be-
tween the idle and mid-range circuits of the carburetor.
-------
C-6
-------
C-8
-------
C-9
-------
C-ll
I
SB
i ] Tf i
1
I
±t
I
„W
id
ML
m
th.
-tb
-+-
uiii
-------
C-12
64-73
CCl4PARISON OF AUTO EXHAUST EMISSIONS FROM TWO MAJOR CmES
A. B. Rose, Jr., R. Smith, W. F. MCMichael, and R. E.
Engineering Research and Development Section
Laboratory of Engineering and Physical Sciences
Division of Air Pollution
Robert A. Taft Sanitary Engineering Center
Public Health Service
U. S. Department of Health. Education. and Welfare
Cincinnati. Ohio 45226
Kruse
Engineering Research and Development Section
Laboratory of Engineering and Physical Sciences
Division of Air Pollution
Bureau of State Services
Public Health Service
U. S. DEPARTMENT OF HEALTH, EDUCATION, A.tID WELFARE
Robert A. Taft Senitary Er.gineering Center
Cincinnati. Ohio 45226
For presentation at the
Air Pollution. Control Association
Annual Meeting, F~uston, Texas
June, 1964
-------
C-l3
CClQtARISON OF AUTO EXHAUST EMISSIONS FROM TWO MAJOR CITIES
A. H. Rose, Jr., R. Smith, W. F. MdMichael, and R. E. Kruse
Engineering Research and Development Section
Laboratory of Engineering and Physical Sciences
Division of Air Pollution
Robert A. Taft Sanitary E~gineering Center
Public Health Service
U. S. Department of Health, Education, and Welfare
Cincinnati, Ohio 45226
INTRODUCTICN
Legislation restricting automotive emissions has been enacted
or is contemplated in such widely diverse areas as California, New
York, and Colorado. The drafting of fair and effective legislation
requires a comprehensive knowledge of the automotive emission levels
in a given community.
In order to predict emission levels for a
community, knowledge of the effects of traffic density, route, and
climate on automotive emissions must be established.
To provide a
basis for developing predictions of emission levels, the U. S.
Public Health Service in the summer of 1962 undertook a program of
exhaust emission studies in several large cities using a new tech-
nique of direct measurement of emissions from vehicles operating
under actual traffic conditions.
This report presents the pre-
lfminary findings from the first two cities studied -- Los Angeles,
California, and Cincinnati, Ohio.
-------
C-14
SURVEY T!:CHNIOL"ES
Previous emission studies have been made by continuOU8
measurements of the exhaust contaminant emi.sions with the vehicle
operating under a fixed-.aode cycle. (1,2) Thil mean cycle was baaed
OD a statistical study of the dist~ibution of mode frequency, mode
duratioD, and rate of change of the transient modes that occur over
an actual traffic route believed to consist of the same proportioD
of each traffic classification as the whole of the area.
Emphasi8
was thus placed on measur~ente of exhaust eaissions under fixed-
mode conditions rather than on me~SUreEent8 under actual road con-
ditions.
While this approEch provides relative emission levels
among individual vehicles or gro~~s of vehicles, baaed on fixed-
mode cycles, it failed to consider the effects on emissions
produced by variations in traffic density, route, and cl1mate.
To overcome the.e licitationl, emi'lion measurements for this
present study were m&de on vehicles eqcipped with a proportional
sampler and driven under actual tr&ffic conditions over selected
routes in two cities.
IP.SnUMZF.!'A'1'!ON
The proportional s~pler ueed was developed by th~ u. S.
Public Health Service(3) in 1962; thil sampler is an electromech-
anical servo device that obtains a composite exhaust 84mple pro-
por tiona I to the eng:!.ne carburetor air flow under a 11 opera ting
conditions. Recording, fl~.-i~teiratir.g circuits built into the
.ampler provide ~eesurements of both total se~le flow and total
exhaus t flow.
Since an absolute meaaure of exhaust emis.ion. vas
-------
C-lS
de8ired, mea8urement8 of exhaust volume and 8ample volume as well
a8 contaminant concentration were &Ade for each test vehicle.
Further, aince both total .ample and total exr~u8t flow were ob-
tained, the proportionality of the .ampler could be check~d.
Teat
run8 that .howed a deviation in prG~orti~nality of more than 3~
were rerun.
Keasur~ents of co~t~in4nt con~entr4tion were ~de after
return of the compo8ite sample to the laboratory.
Hydroc&rbon.
were measured by a Beckman LIB infrared anslyzer Model l;A equipped
with an n-hexane detector and by a Beckman Model 109 flame ionization
detector.
Carbon monoxide and carbon dioxide were mea.ured by
Beckman LIB Model 15A infrared a~lyzer. s~~sitized with carbon mon-
oxide and carbon dioxide respectively.
Oxides of nitrogen were
measured by means of a modified Salt~n t~c~i;ue.
VEH!~U: }.!D p.m."!'! ~~:.E!:'!':(\N
Emission measurements for all ve~icles tested were made under
average traffic conditions.
To est.cliah tne effects of traffic
density on emieaion levels, five v~hici!! wer~ tested ~cder both peak
and offpeak traffic conditionJ.
De=~~!e of the difficulties in pri-
vate vehicle procurement and the inc~e~aa ~ test time required for
this direct measurement prc=ed~re, twe~ty ~riv&t!ly owned vehicle.
and twenty rental vehicles were tested in ea=h city.
The privately
owned vehicles were randomly selected by .t~~dard statistical tech-
niques from an available p~~~la~ion of 300 to 400 cars that were be-
lieved, on the basis of the inc=~e differenti&l cf the vehicle owner.,
to be a. nearly representative a. pol!ible of each city'. car
-------
C-16
population, Table. 1, A and B.
The di.tri~~ticn of vehicle. age.
for the rand08 vehicle .ample. in both citiel covered an 8 year
range, varying from 1955 to 1963 medel..
The randoa .mplea in-
eluded both .ix and eight-cylinder e~gine. with both manual and
automatic tran.mi..ionl.
HAn~l trans.i5si~1 in each rand08
.ample accounted for 20 to 30 ~er cent of the !ample population.
The rental vehicle. te.ted wer~ late model Ford. and Chevrolet.
with automatic tranemission..
Th1, set of vehicles, being ea.ier
to procure than the random sLmple y~hiclee, WAS ~.ed to furni.h
background emislion data to the r1ndom sample. to further verify
the trends developed.
The teat vehicles were operated on the
fuel normally uaed by the vehicle cwner.
The requirement for developi~g a driving cycle representa-
tive of the traffic conditicn. for each specific area under .tudy
was eliminated by selectir.g first5 tr&ffic ro~tes that represent
the ba.ic categories of traffic in al~ ~rban areal and .ecQnd, a
aeasurable vehicle parameter aSI~,~i&te~ with tte v&ric~. route
categorie. that can be reliably rel~ted to emi!!ion &eaaur~ent..
Four traffic categori~a were est.bliah!d:
b~aine'81 re!idential,
arterial ~nd freeway.
Exha~Bt e~iaaiona are ex?reaaed b~th a.
the concentrationa of cont~minanta A~d a. p~~~d8 of contLminant.
emitted per vehicle mile traveled.
Thi. latter method of expre..-
ing emissions was selected for two r~~~ons:
1) it is consistent
with average traffic volume data for majcr m!trc?olit&~ areal, i.e.,
vehicle miles traveled; a~d (2) it can be rel~ted directly to the
u.eful work performed by the automobile ~nder a given serie. of
driving conditions.
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C-17
EVALUATION TECHNIOUE
Analysis of the eaission data for individual vehicle. iD-
dicated that avera2e vehicle SDeed i8 a aeasurable para.eter that
provides an adequate aeasure or index of 88ilsions froa a specific
route.
This parameter is related to traffic volu.e and route con-
ditions, since the average vehicle speed reflects the engine power
demands required by variations ~n tc~ogr~phy of th~ r~~te .s well
as acceleration, deceleration, cr~ise and idle driving aodes.
Becaule of the variations inherent &8Ong vehicie., eaission
levels in different cities can be compAred only by a statistical
method that considers both vehicle speed and eaislion level., ex-
pressed either as concentration or &s total weight emitted per
vehicle mile.
Preliminary evaluaticn of the data for ..ission.
of hydrocarbon, carbon monoxide, and carbon di~xide indicate. that
this empirical relationship between speed and emission level can
be best satisfied by a p~.er function.
The emission data for
individual vehicles were therefore combined for the four route.
and fitted to a power function (Y-AXb) by the leaat .quare. re-
gression technique.
Correlation coefficienta were determined to
establish the degree of fit of each cl&s. of emission aeasurements
for both cities.
The significsnce of eaisaicn level-&ver~ge .peed
trends in the cities was established by an analysi. of co.variance.
Emi.sions in pounds per vehiel! mile traveled were c08puted
~y calculating the total weight of contaminants emitted over each
route from concentration and total exhaust flew values, and dividing
by route length in miles.
This calc~lation assumed a hydrogen to
-------
C-18
carbon ratio of 1.85 to 1.
Since the hydrogen to carbon ratio de-
pend. on exhaust compo.ition, the exhaust. produced by fuel. of
varying compo.ition were analyzed chromatographically to e.tabli.h
the hydrogen to carbon ratio.
Thi. a.suaption, therefore, .hould
not produce an error greater than t 5~ in calculated emis.ion
weights.
RESULTS
Comuarison of Emissions bv Concentration
The initial approach to a compari.on of emission levels in
the two cities was based on exhaust emission concentrations.
Figures
1 through 4 indicate the regression fit of the power function of
concentration data for the combined four routes versus average
vehicle speed plotted on scatter diagrams of the emission data
for hydrocarbon, carbon monoxide and carbon dioxide.
Figure. 1 and
3 represent the random vehicle s&8ple; Figures 2 and 4, the rental
vehicle sample.
Variation in concentration of exhaast hydrocarbon. with
vehicle speed for the combined four traffic routes in the two citie.
is shown in Figures 1 and 2.
The trends for both cities, based on
either the infrared or the flame ionization analyse8, show a general
decrease in hydrocarbon concentration with increasing average vehicle
.peed.
The effect of average vehicle speed on carbon monoxide and
carbon dioxide concentrations in the exhaust is shown in Figures 3
and 4.
As would be expected from the hydrocarb~n trend, the carbon
monoxide concentration decreases and the carbon dioxide concentration
increases with increasing average vehicle speed.
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C-19
Correlation coefficients for the empirical relationship be-
tween average route speed and concentration of hydrocarbon, carbon
aonoxide and carbon dioxide for each city, Table 2. indicate that
although the correlations are statistically valid, the degree of
correlation is only fair.
In contrast to the relationships for
these three contaminants, oxides of nitrogen concentrations showed
no such variation with average vehicle speed, remaining essentially
constant with increase in average speed.
The relationship with
air-fuel ratio, however, as expected on the basis of previous data,
showed an increase in oxides of nitrogen concentration with increas-
ing or enleaning air-fuel ratios, Figures 5 and 6.
Further, the
correlation coefficient for the relationship of oxides of nitrogen
concentration with air-fuel ratio, Table 2, indicated that the
degree of correlation is excellent.
Within the vehicle-speed range of this study, the total
volume of air consumed by the engine, when expressed as cubic feet
per mile traveled, decreases with increasing average speed, as
shown in the plot of average vehicle speed vers~s air consumption,
Figure 7.
This trend is consistent for both cities and shows a
good correlation, Table 2.
ComDarison of Emissions bv Wei2ht
The second comparison of emission levels with average route
speed was made on the basis of pounds of contaminant emitted per
vehicle mile traveled, Figures 8 thro~gh 11.
Again, the regression
fit of the power function of emission in pounds pe~ vehicle mile
versus average route speed was plotted on scatter diagrama of the
-------
C-20
emission data for the four combined routes.
Figures 8 and 10 repre-
sent the random vehicle sample; Figures 9 and 11 cover the rental
vehicle sample.
The weight of exhaust hydrocarbon and carbon monoxide ea1tted
per vehicle mile of travel decreases with increase in average vehicle
speed, Figures 8 through 11.
This relationship is consistent for both
cities.
The effecf of average vehicle speed on b~th hydrocarbon and
carbon monoxide emissions is proportiocately greater during the low-
speed condition below 20 mph.
This speed range represents the resi-
dent!a1 and business routes; the high percentage of stop and .tart
driving required in these traffic conditions causes an increase in
acceleration, deceleration, and idle operation and accounts for the
higher emission rates and vehicle air consumption in this lower
average speed range.
Figures 9 and 11 indicate the effect of vehicle speed on
pounds of carbon dioxide emitted per vehicle mile.
As the figures
show, increase in vehicle speed produces a conli8tent decrease in
pounds of carbon dioxide emitted per veh~cle mile.
This is in con-
trast with the preceding concentration trend which indicated a slight
increase in carbon dioxide concentration with increase in average
speed.
This effect of the greater decreas2 in air ccns~tion per
mile overriding the smaller increase in carbon dioxide concentration
becomes apparent when the emissions are pre3ented on a weight per
mile basis instead of a concentration basia.
The relationship between average r~~te speed and emission
levels expressed as pounds per vehicle mile .hows a good correlation,
in contrast to the fair correlation shown for the emi..ion levels by
-------
C-2l
concentration, Table 2.
The correlation coefficient. for emi..ion.
on a weight basis range from 0.57 to 0.84, whereas the correlation
coefficients on a concentration basis range from 0.25 to 0.61.
Thi.
would be expected since the emission level. calculated as weight per
vehicle mile more nearly reflect the w~rk performed by the engine.
Again, as with oxides of nitr~gen eMis.ion values based on
concentration, mass oxides of nitrogen emissions expreseed &. pounds
per vehicle mile traveled show no rel&ti~nahip with average vehicle
speed, remaining essentially constant with increase in,average speed.
The relationship with air-f~el ratio, however, again indicates an
increase in mass emission of oxides of nitrogen with increa.ing air-
fuel ratio, Figures 12 and 13.
Correlation coefficient. for this
relationship, Table 2, indicate the same high degree of correlation
as with the values based on concentration.
Variation Amon2 Vehicles
The data indicate the scatter in the plots of concentration
and of contaminant weight per vehicle mile versus &versge route
speed results fundamentally fr~ the extreme vari&tion in emission
levels among vehicles and not fre. poor correlation. between emil-
sion level and average route epeed.
This i8 shown in Figures 14
through 16, in which regression 1inas of the emission data for
hydrocarbons and carbon monoxide in pounds per vehicle mile versus
average route speed are plotted for each i~dividua1 vehi~le in the
Los Angeles random vehicle s~le.
As these fi~~=ea show, each
vehicle follows the same ge~eral power functicn of p~undl of
emission per vehicle mile versus average vehicle speed, forming
-------
C-22
a fam11y of curve. with generally the .ame Ilope.
Specifically,
the pooled eltimate of variance of the data about the regrellioD
line. for individual cars is 8m&ll, varying from 0.0024 to 0.0061,
in contrast to the variance of the total emission data about a
single regression line, which ranges from 0.035 to 0.115.
This
order of magnitude difference in variance substantiates the
premise that the spread of emission levels result. ~asically fro.
the differences among individual vehicle,.
Comoarison of Emissions in the Tw~ Cities
To establish the significance of the emission weight versus
average speed relationships in the two cities, an analysis of
co-variance was used to determine whEther the regression lines
for pounds of contaminant emisaions per vehicle mile v~rSU8
average speed differed significa~tly, Figures 8 and 10.
This
analysis was based on the random vehicle eamples since they more
nearly represent the actual vehicle distribution found in the
respective cities.
The rental vehi:le sampl~ was not used becau.e
it is definitely biased by the limited age, transmission type, and
vehicle make that compose its vehicle distribution.
For hydrocarbons measured by the flame ionization analyzer,
and for carbon monoxide and carbon dioxide, the regression lines
for the two cities were not significantly different at the 95~
confidence level.
For hydrocarbo~s m~a8~red by nondi.persive
infrared analyzer in the two cities, however, tha regression
lines were statistically diff~rent.
This difference apparently
-------
C-23
results fro. the variation in the response of this hydrocarbon
instrument to different hydrocarbon compounds appearing in auto-
8Obi1e exhaust.
Differences in the gasoline used in Cincinnati
and Los Angeles may be responsible for such differences in the
products of combustion.
Figure 17, which shows the ratio of non-
dispersive infrared response to fl&m~ ionization response,
indica~es that thil ratio incr~sles at a higher rate, with in-
crealing vehicle speed, for Cincinnati than for Los Angeles.
This change in ratio explains the appa=ent different~rates of
decreale of hydrocarbons emitted al vehicle speed increases,
Figures 1 and 8.
In Cincinnati t~e rate of decrease is lesl
with the result that the difference in ~ounds of hydrocarbon
emitted, mealured with the nondispersive infrared analyzer, be-
comes increasingly greater betwe~~ these cities as vehicle speed
increases.
Cincinnati data show th~ highest value.
On this
basis, it is believed that the statistical difference shown
between Cincinnati and Los Angeles fo~ the po~nds of hydrocarbon
per vehicle mile, mea8u~ed by this ~eth~d, ia an instrument
characteristic and therefore is not rsal.
Effects of Peak Ve~sus Off~sak Tr~ff1~
Traffic density ia reflect~d in both engin2 power demand
and average vehicle speed and as such influences exhaust cone en-
tration levels and engine air consumption.
A special study of
peak versus offpeak traffic conditions was undertaken to evaluate
this effect.
-------
C-24
Five vehicles were run on the business. arterial. and free-
way routes in Los Angeles. under both peak and offpeak traffic
conditions.
The data indicate that the mean emission level of
test vehicles varies about the plot for the weight per mile
versus average speed curve.
Because of this variation. compart-
80ns between peak and offpeak values of weight of emission per
mile cannot be made directly with the p=pulation mean value.
Comparisons can be made, however, between tt.e r,ti~s of measured
peak to offpeak weight emission per mile values with the same
ratio values calculated using the regression line for the specific
contaminant and speed.
Table 3 shows the measurements in terms of
mean values for the freeway route in Lea I~gales.
Since the arterial
and business routes indicated no sig~ific&~t difference in speed be-
tween peak and offpeak traffic co~ditiona, these ro~:ea w~re not
used in the comparison.
The data indicAte thAt the two ratios. i.e..
calculated and measured, are the e~9 for hydro~arbon measured by both
the flame ionization analyzer or the n~~1i5?;rsive infrared analyzer
and for carbon monoxide.
It is cc~;l~ded th~t the effect of peak
versus offpeak traffic on contemi~a~t e~iasi)~ is ba8ically a
function of the changes in average Sf sed for the r~~t~ under con-
sideration and does not effect the ;~~~d fer vehicle nile emission
level at the specific measured rc~tE speed.
S"'~..RY
Although the ~ission re~ult2 yre3ented fer Los Angeles and
Cincinnati are prel~i~ary, since S~~d~=3 ~re ~~~t~~~ing in other
cities, certain conclusions ca~ be ~~de on the basis of tt.e present
data.
-------
C-25
1.
Emissions, expressed as pounds of contaminant emitted
per vehicle mile traveled, are a function of average
route speed regardless of the chArscteristics of the
specific route, and can be best shown as a logarithmic
function of pounds of cor.t~inaat ~itted per vehicle
mile versus average vehicle !peed.
2.
Emissions expressed ae Cjnc!nt~tion are a leBa valid
measurement of exhs~st etmc3?heric cont&m~nat~on than
emissions expressed &8 pounds per v~hicle mile
traveled.
The re~son is t!lieved to be the variability
of combustion air c~~3~pticn amG~g vehicles and vari-
ability among route :h~~a:teris~1ce.
3.
The road ~iasion dsts ~~;~=!a!d as a log&rithmic
function of pounds of co~~a~~~~t e~1ttad fer vehicle
mile versu; aver~ge r~~t~ E~~ad stow ~c eignificŁut
difference between l~a iL~gel~a ~nd C~n:i~nsti.
4.
The effect of p~Łk VEra~s Jff?~&k t~~ffic cn ~i!siona,
expressed aa p~und2 cf cc~:~~n~r.t e~itted fer vehicle
mile traveled, i3 bŁzi:~lly a f~nctic~ cf tr.e ch~nge in
average route spe~d.
-------
C-26
UFIllI1fCES
L.
Ball, G. C., "aeport on Exhault lmiuionl from 194 California
Vehicles," California Motor Vehicle Pollution Control Board,
June 19, 1962.
2. Wa)', G., Fagle)'. W. S., "Field Surve)' on Exhault Gal Compo.ition,"
SAE Annual Meeting, Detroit, Michigan, January 13, 1958.
3.
Smith, I.., aose, A. R., Jr., and lrule, I.., "An Auto Exhau.t
Proportional Sampler," APCA Annual Me.ting, Detroit, Michigan,
June, 1963.
-------
C-27
TABLE 1A
DESCRIPTION OF CINCINNAn TEST VEHICLES
RANDOM SAMPLE
CAR NO. ~ ~ ODOMETER CYLINDERS DISPLACEKENT TRANSMISSION
1 Old.. 1960 48,623 v8 371 Auto.
2 Chev. 1960 22 ,680 v8 283 Auto.
3 Chev. 1959 45,345 6 236 Man.
4 Ramb 1er 1961 12,577 6 196 Man.
5 Chev. 1961 25.176 6 236 Man.
6 Ford 1956 36,069 v8 292 Auto.
7 Buick 1961 15,133 v8 215 Auto.
S Ford 1957 65.464 v8 292 Auto.
9 Ford 1959 38.709 v8 29'2 Auto.
10 Mere. 1960 49.306 v8 312 Man.
U Chev. 1957 54.174 v8 283 Auto.
12 Ford 1959 42,874 v8 29'2 Auto.
13 Chev. 1959 36.797 6 236 Auto.
14 Falcon 1960 42.611 6 144 Auto.
15 Chev. 1959 36.727 6 236 Auto.
16 Pontiac 1956 59.454 v8 317 Auto.
17 01ds-F85 1963 4.202 v8 215 Auto.
18 Rambler 1962 4.390 v8 327 Auto.
19 Chev. 1958 40 . 380 v8 283 Auto.
20 Ford 1957 49.779 v8 272 Auto.
-------
C-28
TABLE IB
DESCRIPTION OF LOS ANGELES TEST VEHICLES
RANDOM SA.v.PLE
CAR. NO. ~ ~ OD0METEa CYLINDERS DISPlACEMENT TRANSMISSION
1 Old.. 1960 28,024 v8 292 Auto.
2 Chev. 1960 58,712 v8 283 Auto.
3 Falcon 1960 22 , 343 6 144 Auto.
4 Chevy II 1963 8,419 6 194 Auto.
5 Ford 1955 54,521 6 223 Auto.
6 Rambler 1962 6,318 6 196 Auto.
1 Chev. 1959 14,741 v8 348 Man.
8 Ford 1955 31,401 6 223 Man.
9 Chev. 1960 18,586 6 236 Auto.
10 Ford 1956 70 ,070 v8 272 Auto.
n Plymouth 1959 72,737 va 318 Auto.
12 Ford 1962 7,686 v8 352 Auto.
13 Chev. 1961 18,937 6 236 Auto.
14 Falcon 1960 38,75-':> 6 144 Kan.
15 Chevy II 1962 16,285 6 194 Han.
16 Old.. 1955 90,944 vS 324 Man.
17 Chev. 1959 138,672 v8 283 Auto.
18 Chev. 1956 62,663 v8 283 Man.
19 Mere. 1956 59,889 v8 312 Auto.
20 Falcon 1961 21,054 6 144 Auto.
-------
TABLE 2
CORRELATION COEFFICIENTS
EMISSIONS
CONCENTRATION WEIGHT
ppm pounds/vehicle mile
RELATIONSHIP
CINCINNATI LOS ANGELES CINCINNATI LOS ANGELES
I RANDOM I . '«TAL RANDOM RENTAL RANDOM RENTAL RANDOM RENTAL
SAMPLE SA.M:PLE SAMPl E SAMPLE SAMF'LE SAKP'LE SAMPLE SAMPLE
::::~'"':- - "'-"-'--='''=':':U':':'. ---~~~.: .::-;.:x:;:...:o.~~.='-== .~~- --==:=--:t::=:; ~.. -_..._--~
HYDROCARBON VS. SP EED
0
0.388 o. 506 O. 561 0.686 0.683 0.697 I
Hex'.rlne 0.302 0 . 720 N
. '"
FTAD 0.369 0.491 0.483 0.476 0.685 0 . 764 0.654 0.688
CO VS. Sl"EED 0.347 0.706 0.510 0.611 0.572 0.841 0.630 0.716
C02 VS. SPEED 0.247 0.601 0.476 0.430 0.623 0.658 0.581 0.613
NOx VS. A/F RATIO 0.800 0.749 0.839 0.605 0.137 0.578 0.TI8 0.402
AlR FLOW VS. SPEED 0.675 0.7~ 0.654 0.677 0.675 0.746 0.654 0.677
-------
C-30
'tUU ~
ROAD EMISSION MEAS1E.~S t'OR FEAX A}o]) C:?lEAX TRAFF!C
LOS AN:;ELES FP.!~7 !\C;n'E
Off Measured Calculated
Measurement Peak Ratio bUo
Peak Peak/Of:peak Peak/Offpeak
Avg. Speed (KPH) 45.2 23.0
Air Consumption (SCrimi.) 50.1 51.5
Hydrocarbon, ppmC, NDIR 1620 2250
Hydrocarbon, 1bs/mi.,~!R 0.00297 0.00418 1.41 1.59
Hydrocarbon, ppmC, FIA 3210 4720
Hydrocarbon, lbs/mi.,?!A 0.00591 0.00909 1.54 1.61
CO, ~, NDIR 1.62 ~.68
CO, lbs/mi., NDIR 0.0612 c. 101+0 1.70 1.89
Route Length. 4.97 miles
Mean Values for 5 cars
-------
CROSS HYDROCARBON (HKKANE) fHOT.g PRACTIOH
VERSUS
AVERAGE VEHICLE SPEED
(RANDOM VEHICLE SAMPLE)
CROSS HYDROCARBON fFIAJ MOLE FRAC
VERSUS
AVERAGE VEHICLE SPEED
(RANDOM VEHICLE SAMPLE)
10.000-- V
1,000
10 20 30
AVERAGE VEHICLE SPEED, ml lea/hour
20 30
AVERAGE VEHICLE SPEED, llcs/hoor
60
riCTJR B 1
-------
CROSS HYDROCARBON (HEXANE) HOLE FRACTION
VERSUS
AVERAGE VEHICLE SPEED
(RENTAL v-vnr.i.R S^.VPLE)
10 ?J 30
AVERAGE VEHICLE SPEED, miles/hour
lO.OOOTTT
CROSS HYDROCARBON (FIA) HOLE FRACTION
VERSUS
AVERAGE VEHICLE SPETO
(RENTAL VEHICLE SVPIE)
o
H
O
o
cd
O
r/J
O
10 20 jj
AVERAGE VEHICLE SPEED, mlleg/hour
FIGURE 2
-------
CARBON MONOXIDE MOLE FRACTION
VERSUS
AVERAGE VEHICLE SPEED
(RANDOM VEHICLE SAMPLE)
AVERAGE VEHICLE SPEED
miles/hour
lOO
CARBON DIOXIDE MOt.g FRACTION
VERSUS
AVERAGE VEHICLE SPEED
(RANDOM VEHICLE SAMPLE)
c
v
o
u
Hi
o.
(d
O
o
t-t
o
1
FIGURE 3
AVERAGE VEHICLE SPEED
lie*/hour
-------
V
o
M
w
ex
Q
I
55
s
ai
CARBON MONOXIDE MT>TJT PRACTIOtf
VERSUS
AVERAGE VEHICLE SPEED
(RENTAL VEHICLE SAMPLE)
CARBOB DIOXIDE MPLE FRACTION
VERSPS
AVERAGE VEHICLE SPEED
(RECTAL VEHICLE SAMPLE)
100
AVERAGE VEHICLE SPEED
mile*/hour
FIGURE k
AVERAGE VEHICLE SPEED
llc«/hour
-------
C-35
OXIDES OF NITROGEN MOLE FRACTION
VERSUS
AIR-FUEL RATIO
(RANDOM VEHICLE SAMPLE)
fcrwi
MOLE FRACTION, ppm
Ł boo
1
200
inn
i
n 1
: '
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10
11
12
13 lU 15
AIR-FUEL RATIO
FIGURE 5
-------
C-36
OXIDES OF NITROGEN MOLE FRACTION
VERSUS
AIR-FUEL RATIO
(RENTAL VEHICLE SAMPLE)
4 CINCINNATI
o LOS ANGELES
1»000
2000
i
1000
600
Cu
O
I
g
1*00
200
100
10
S
T ^^
11 12
13 1U 15
AIR-FUEL RATIO
FIGURE 6
-------
C-37
VEHICLE AIR CONSUMPTION PER MILE
VERSUS
AVERAGE VEHICLE SPEED
(RANDOM VEHICLE SAMPLE)
1000 P^
I
U
l00"
^^_\_ ~^~__ j~^__^
'4
---
CINCINNATI
i^LbSjNGELESJ|
. --
------- 1;- ---
lli
:Ł}:-:
T~l
H-
10 20 30
AVERAGE VEHICLE SPEED, mlles/houc
60
-------
POUNDS OP CROSS HYDROCARBONS /HEXANE)
EMITTED PER MILE
VERSUS
AVERAGE VEHICLE SPEED
(RANDOM VKIITCI.F. SAMPLE)
c
*>
c
o
o.
a
v>
en
h-l
U
at
1
in
10 20 30
AVERAGE VEHICLE SPEED, mllea/hour
POUNDS OP CROSS HTDROCARBOHS fFIAl
EMITTED PER MILE
VERSUS
AVERAGE VEHICLE SPEED
(RANDOM VEHICLE SAKPLK)
e
**»
ffl
8
e
Q
5!
2
M
U
nCOKE 8
20 30 60
AVERAGE VEHICLE SPEED, miles/hour
-------
POUNDS OF CROSS HYDROCARBON
EMITTED PER
VERSUS
AVERAGE VEHICLE SPEED
(RENTAL VEHICLE SAMPLE)
.001
10 20 30
AVERAGE VEHICLE SPEED, miles/hour
.our.
gUIIMDS OF CROSS- HTOROTABBOMS
EMITTED PER MILE
VERSUS
AVERAGE VEHICLE SPEED
(RENTAL VEHICLE SAMPLE)
"
8.
o
V)
e/1
co
to
.001
FIGURE 9
IO 80 30
AVERAGE VEHICLE SPEED, .lie./hour
-------
POUNDS OP CARBON MONOXIDE
EMITTED PER MILE
VERSUS
AVERAGE VEHICLE SPEED
(RANDOM VEHICLE SAMPLE)
i
ARM:; y.^.-o/nr. E-.ISSIO::, pounds/mile
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10 20 30 6O
AVERAGE VEHICLE SPEED, miles/hour
10
30
66
AVERAGE VEHICLE SPEED, Biles/hour
FIGURE 10
-------
POUNDS OP CARBON MONOXIDE
EMITTED PER MILE
VERSUS
AVERAGE VE1HC1.E SPEED
(RFNTM. VEHICLE SAMPLE)
:MI
10 20 30
AVERAGE VEHICLE SPEED, nlles/hour
POUNDS OF CARBON DIOXIDE
EMITTED PER MILE
VERSUS
AVERAGE VEHICLE SPEED
(RENTAL VEHICLE SAMPLE)
6.0--
n
o
C
3
O
CL
to
n
5
X
o
g
a:
5
10 JO 30 60
AVERAGE VEHICLE SPEED, milea/hour
FIGURE 11
-------
C-42
POUNDS OF OXIDES OF NITROGEN EMITTED
.OliO.
mods/Bile
? i
"ROC EN EMISSION, px
1 8 c
[ a <
^^
g
/vr\ 1 <
VERSUS
AIR-FUEL RATIO
(RANDOM VEHICLE SAMPLE)
1 : 1
, ! .
1 : ! .
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-C INC 11
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10 11 12 13
AIR-FUEL RATIO
FIGURE 12
15
-------
C-43
.
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POUNDS OF OXIDES OF NITROGEN EMITTED
VERSUS
AIR-FUEL RATIO
O
o
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AIR-FUEL RATIO
1U 15
FIGURE 13
-------
C-44
POUNDS OF CROSS HYDROCARBON (HEXANE)
EMITTED PER MILK
VERSUS
AVERAGE VEHICLE SPEED
(LOS ANGELES RANDOM VEHICLE SAMPLE)
.100
M .010
VJ
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.001
10 20 30
AVERAGE VEHICLE SPEED, miles/hour
FIGURE 1U
-------
C-45
POUNDS OF CROSS HYDROCARBONS fFIA)
EMITTFD PER MILE
VERSUS
AVERAGE VEHICLE SPEED
(LOS ANGELES RANDOM VEHICLE SAMPLE)
.001
1C 20 j,0
AVERAGE VEHICLE SPEED, miles/hour
FICL-RE 15
-------
C-46
POUNDS OF CARBON MONOXIDE EMITTED PER MILE
VERSUS
AVERAGE VEHICLE SPEED
(LOS ANGELES RANDOM VEHICLE SAMPLE)
10 20 30 60
AVERAGE VEHICLE SPKF.D, miles/hour
FIGURE 16
-------
C-47
-------
A P PEN D I X
D
ESTIMATING EMISSION REDUCTIONS FROM
TRAFFIC FLOW TECHNIQUES
As indicated in the previous appendix, motor vehicle exhaust
emissions (carbon monoxide) are lower in freely-flowing traffic than in
congested, stop-and-go conditions.
Hence, traffic flow improvements can
result in reduced emissions.
These improvements, however, also tend to
increase roadway carrying capacity at the same time.
Consequently, in
estimating the emission reductions from traffic flow improvements one
must consider both the average per vehicle emissions (which may be lower
as a result of improved flows and higher average speeds)and the volume
of vehicles using the roadway (which may be higher as a result of greater
roadway capacity).
In the latter connection, consideration is required of three
factors:
(1) the increase in roadway capacity that results from traffic
flow improvements; (2) the rate at which increased capacity is utilized
(bearing in mind that traffic flow improvements tend to generate ad-
ditional trips that otherwise would not have been made); and (3) the
net emission trade-off over time between potentially higher speeds and
potentially higher volumes along a given roadway following traffic fiow
1
Each of these factors is discussed below.
improvements.
1. Primary attention in the following discussion is on peak-hour
capacity. It is not particularly meaningful to use maximum daily
capacity as a measure since one peak hour may account for more than
10 percent of total daily travel. Conversely, almost no trips may
be made during other hours (e.g., between midnight and dawn).
-------
D-2
Increase in Roadway Capacity
Determining the increase in roadway capacity following traffic
flow improvements requires knowledge of speed-volume relationships in
urban areas.
Because of relatively high traffic volumes and low speeds
characteristic of central business district (CBD) streets, this area is
likely to show the greatest potential for emission reductions from traffic
flow improvements.
Unfortunately, typical speed-volume relationships
used on urban arterials and rural roads have not been developed for
downtown streets; major difficulties have been encountered in attempting
to develop speed and volume measurements because of differences in the
1
functions and services of CBD streets.
Since available data do not permit
an estimate of speed and volume changes from traffic flow improvements on
CBD streets, we must draw from recognized data and relationships which
2
have been developed for urban arterials.
1.
As the
Highway Capacity Manual notes,:
It is not yet feasible to develop charts or curves
presenting basic speed-volume relationships for
extended sections of downtown streets ... At present,
with the current limited knowledge of the complex
relationships which govern downtown traffic flow, it
is not possible to develop even typical speed-vie
[volume to capacity] ratio relationships. The capa-
cities of apparently similar downtown streets vary
widely due to differing environmental [local traffic
frictions, street geometry, etc.] conditions.
Highway Research Board, Highway Capacity Manual, Special Report 87
(Washington, D.C.: National Academy of Sciences-National Academy of
Engineering, 1966), p. 332. (Emphasis added.)
2. Though the examples do not employ data from any specific city, they
are based upon observations and relationships which have been verified
over a relatively long period of time in a number of urban areas.
Consequently, the conclusions appear generally valid for most cities.
Urban arterials are defined in the Highway Capacity Manual as "... major
streets and highways outside the central business district having either
(1) intersection signalization at an average spacing of one mile or less, or
(2) speed limits of 35 mph or less due to extensive roadside development. II
Ibid., p. 318.
-------
D-3
The illustrations which follow do not necessarily reflect CBD street
conditions, but they do represent the only data presently available for
any form of urban street.1
Rate of Increased Capacity Utilization
As explained in Chapter 3, traffic growth can be considered to
consist of two components:
(1) long-term or trend growth and (2) "induced"
or "generated" growth (i.e., the attraction of new trip-makers because of
n~w capacity or improved conditions).
To some extent, long-term traffic
growth results from factors different from those 'tlhich stimulate "induced"
growth (e.g., growth in incomes may stimulate long-term trip~making while
traffic flow improvements may stimulate "induced" growtn).
However, both
growth rates reflect to some degree the extent to which existing roadway
capacity is at "saturation."
Because all thes~ factors interact and their dynamics are imper-
fect1y understood, we have had to make a variety of assumptions about
traffic growth to illustrate the effects of increased volume on speed
(and subsequently on emissions) for typical urban arterials.
Under
assumptions for Case 1, no traffic flow techniques are implemented.
Consequently, no induced traffic is assumed, only trend growth at
3 percent per annum.
Case 2 includes an identical trend rate and an
induced traffic stream anticipated to utilize (by the end of year 2)
1. In deriving the speed and volume factors used in< the illustrations
below, Table 10.13 and Figure 10.3, Curves II and III from the Highway
Research Board, Highway Capacity Manual, Special Report 87 (Washington,
D.C.: National Academy of Sciences-National Academy of Engineering,
1966), were used. These curves show levels of service along with overall
average travel speeds and volume-to-capacity ratios for urban arterials.
-------
D-4
the capacity increase made possible by traffic flow improvements.
In Case 3, the same assumptions are made as in Case 2 with respect to
induced traffic, but the rate of trend growth is anticipated to decline
as roadway capacity approaches saturation.
Table D-1 illustrates, for
each of the three cases, the impacts on speed and volume over a five-
year horizon following implementation of traffic flow techniques in
Year 1.
Impacts on speed and volume result from a "package" of traffic
flow techniques (assumed to consist largely of improved signalization)
on a
typical urban arterial.
Roadway capacity in the base year (i.e.,
prior to any improvements) is assumed to be approximately 1,500 vehicles
per hour per lane for one-way direction, and the average vehicle speed
is assumed to be 15 miles per hour.
Traffic flow techniques are assumed
to be implemented in year 1, at which time speed increases 5 miles per
hour.
Increased vehicle speeds from implementation of traffic flow
techniques are felt in year 1, although the induced traffic generated
by these improvements is not assumed to occur until year 2.
This as-
sumption about induced traffic is probably conservative, since in most
cities drivers respond rather rapidly to traffic improvements.
-------
Table D-l
ILLUSTRATIVE IMPACTS OF TRAFFIC FLCM TECHNIQUES ON S PEED AND VOLUME 1
F act 0 r s
Base Year Year 1 Year 2 Year 3 Year 4 Year 5
Case 1: Trend 3%/Induced None/No Traffic Flow Techniques
1500 1500 1500 1500 1500 1500
1500 1545 1591 1639 1688 1739
o 0 0 0 0 0
1500 1545 1591 1639 1688 1739
1.00 1.03 1.06 1. 09 1.13 1. 16
15 14 13 12 11 10
Sou r c e
1. Capacity (vph/lane/cne way)
2. Trend Volume (3% p.~.)
3. Induced Volume (0)
4. Total Volume
5. Volume to Capacity Ratio
6. Speed (mph)
Assm:1ed
Assu:f\cd
As SU't12 0
Line 2 + Line 3
Line '+ ~ Line 1
. ')
Interpo1a t:ionL
Case 2:
Trend 3%/Induced 1wo Years to Capacity/Traffic Flow Techniques in Year 1
Capacity (vph/1ane/one way) 1500 1750 1750 1750 1750 1750 Assumed t:!
7. I
8. Trend Volume (3% p.a.) 1500 1545 1591 1639 1688 1739 Assumed V1
9. Induced Volume 0 0 159 250 250 250 Assumed
10. Total Volume 1500 1545 1750 1889 1938 1989 Line 8 + Line 9
11. Volume to Capacity Ratio 1.00 .88 1.00 1.08 1.11 1.14 Line 10 : Lin1 7
12. Speed (mph) 15 20 15 13 12 10 Interpo1~tion
Case 3: Trend 3% - 2% 1. 5%/Induced Two Years to Capacity/Traffic Flow Techniques in Year 1
13. Capacity (vph/lane/one way) 1500
14. Trend Volume (3%-2%-1.5% p.a.)1500
15. Induced Volume 0
16. Tota 1 Vo lume 1500
17. Volume to Capacity Ratio 1.00
18. Speed (mph) 15
1750 1750 1750 1750 1750 Assumed
1545 1591 1623 1647 1672 Assumed
o 159 250 250 250 Assumed
1545 1750 1873 1897 1922 Line 14 + Line 15
.88 1.00 1.07 1.08 1.10 Line 16 : Line 13
20 15 14 13 11 Interpo1ation2
1. Traffic flow techniques implemented on an urban arterial and assumed to consist primarily of ir.lproved signali-
zation, as explained in text.
2.
From Highway Capacity Manual, 1965, as explained in text.
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D-6
Net Emission Tradeoff
Having obtained the speed-volume levels following implementation
h 1 . .. 1
of traffic flow techniques, we can now calculate t e resu t1ng em1SS10ns.
Table D-2 summarizes the impacts of implementing traffic flow techniques
on emissions over a five-year period.
As indicated for Cases 2 and 3
involving traffic flow techniques, absolute emissions decrease for only
the year immediately following implementation, when emissions will be
some 17.6 percent less than the base year.
For air pollution control
purposes, however, a more meaningful comparison of these two cases would
be with Case 1 (i.e., emissions on a roadway segment where no traffic
flow techniques have been implemented).
Using this relative measure,
Table D-2 shows that emissions along the arterial in Cases 2 and 3 would
be less in year 2 than the resulting emissions if no improvements were
made.
For all subsequent year~ emission levels would be higher than if no
traffic flow techniques were implemented at all.
In year 5, for example,
emissions would be approximately 24 percent greater for Case 2 than for
Case 1 and 19 percent greater for Case 3.
The reasons for this increase in relative emissions following
year 2 can be readily ascertained from Table D-2.
Although speeds fol-
lowing traffic flow improvements in Cases 2 and 3 are always higher than
1. The estimates which follow are based on preliminary EPA data on carbon
mono;dde emissions as a function of speed for pre-controlled vehicles, as
explained in Appendix C. See M. J. McGraw and R. L. Duprey, "Compilation
of Air Pollutant Emission Factors," Preliminary Document, Environmental Pro-
tection Agency, April 1971. (Mimeographed.) Consequently, application of
these data to present in-use vehicles is somewhat speculative. However, the
substitution of any similar speed-emission relationship for the above-cited
one should not substantially alter our basic conclusions.
-------
Table D-2
ILLUSTRATIVE IMPACT OF TRAFFIC FLOW TECHNIQUES ON EMISSIONS
F act 0 r s
Base Year
Year 1
Year 2
Year 3
Year 4
Year 5
Sou r c e
Case 1:
Trend 3%/Induced None/ No Traffic Flow Tehniques
1. Volume (vph/1ane/one way) 1500 1545 1591 1639 1688 1739 Table D-1, Line 4
2. Volume Increase over
Base Year (%) 3 6 9 13 16
3. Speed (mph) 15 14 13 12 11 10 Table D-1, Line 6
4. Emission Factor 1.00 1.10 1.17 1. 23 1. 33 1.43 McGraw, Duprey1
5. Change in Emission Factor
over Base Year (%) 10 17 23 33 43
6. Net Emissions Tradeoff (%) 13 24 34 50 66 (Line 1 x Line 4)-1500
1500 x 1.00
Case 2: Trend 3%/Induced Two Years to Capacity/Traffic Flow Techniques in Year 1
7. Volume (vph/1ane/one way) 1500 1545 1750 1889 1938 1989 Table D-1, Line 10
8. Volume Increase over
Base Year ('7.) 3 17 26 29 33
9. Speed (mph) 15 20 15 13 12 10 Table D-1, Line 12
10. Emission Factor 1.00 .80 1.00 1.17 1. 23 1.43 McGraw, Duprey1
11. Change in Emission Factor
over Base Year (%) -20 0 17 23 43
12. Net Emission Tradeoff (%) -18 17 49 59 90 (Line 7 x Line 10)-1500
1500 x 1.00
Case 3: Trend 37. - 2% - 1.5%/Induced Two Years to Capacity/Traffic Flow Techniques in Year 1
13. Volume \vph/1ane/one way) 1500 1545 1750 1873 1897 1922 Table D-1, Line 16
14. Volume Increase over
Base Year (%) 3 17 25 27 28
15, Speed (mph) 15 20 15 14 13 11 Table D-1, Line 18
16. Emission Factor 1.00 .80 1.00 1.10 1.17 1. 33 McGraw, Dupreyl
17. Change in Emission Factor
over Base Year (%) -20 0 111 17 33
18. Net Emission Tradeoff (%) -18 17 37 48 70 (Line 13 x Line 16)-1500
1500 x 1.00
t::I
I
....
1.
EPA data as explained in text, but with emission factor in base year at 15 miles per hour adjusted to equal 1.00.
-------
D-8
for Case 1 (with one exception where it is identical), the relative
reduction in per vehicle emission factors associated with the higher
speeds becomes rapidly overwhelmed by the additional number of vehicles
using the arterial.
Thus, for Case 2, although the higher average speed
in year 4 (12 miles per hour as compared to 11 miles per hour for Case 1)
results in 10 percent relative reduction in the emission factor (from 1.33
to 1.23), relative traffic volume increases approximately 16 percent (from
29.2 to 12.5) -- a resultant 8.9 percent (from 58.9 to 50.0) relative
increase in emissions.
These examples show the rapidity with which emis-
sion reductions from traffic flow improvements are overvlhelmed by increased
vehicular vOlumes,l and that, even over a short-term of three to five years,
relative emissions can be considerably greater than if no imprDvements were
made at all.
Consequently, as indicated in Chapter 3, traffic flow improvements
should be viewed only as extremely short-term measures, unless traffic
volumes can be reduced or restrained.
For example, if motor vehicle
restraints could prevent substantial increases in traffic volumes, po-
tential emission reductions could be considerable.
To illustrate this
point an additional example has been developed.
1. The rapidity with which emission reductions are offset by higher
vehicle volumes is, as explained above, a function of the assumptions
made about the traffic generation process (as VIell as the initial volume
to capacity ratio of the arterial). Variations in these factors will
alter the time dimension to some extent, but will not alter the basic
dynamics.
-------
D-9
Reducing Traffic Volumes with Motor Vehicle Restraints
In Case 4, we assume that a motor vehicle restraint program
(consisting of doubling parking prices and reducing significantly on-
street parking) is implemented, and further that this program results
in a 20 percent decline in vehicle miles trave1ed.1 Trend growth is
assumed to continue at a rate of about 3 percent in year 1, but then
decline to about 2 percent as a result of the restraint, while induced
trips would increase from 10 to 16 percent as drivers adjust to changes
in parking prices and as parking price increases are passed on to consumers.
Table D-3 summarizes these assumptions and illustrates the impacts of a
motor vehicle restraint program on vehicle speeds and volume.2
Table D-4 indicates the resulting net emissions trade-off.
As shown
the absolute emissions decrease for each of the five years following imple-
mentation of a motor vehicle restraint program.
When viewed relative to
Case 1 (i.e., no action taken),emission reductions are even more substan-
tial. ranging from approximately 56 percent fewer emissions in year 1 through
3 to 74 percent fewer emissions in y~ar 5.
Thus, motor vehicle restraints
capable of reducing traffic volumes on an urban arterial could have a sub-
stantial impact in reducing motor vehicle emissions.
1. For further discussion, see Appendix F, "Estimating Emission Reductions
from Motor Vehicle Restraints."
2. Conceivably, emission reductions could be significantly greater with
motor vehicle restraints and traffic flow techniques, although the incre-
mental value of the latter is difficult to determine without computer
simulation.
-------
Table D-3
ILLUSTRATIVE IMPACTS OF TRAFFIC FLOW TECHNIQUES AND
MOTOR VEHICLE RESTRAINTS ON SPEED AND VOLUME
F act 0 r s
Year 1
Year 4
Sou r c e
Base Year
Year 2
Year 3
Year 5
Case 4:
Double Price of Parking for 2~1o Vehicle Reduction/Trend 3% and 2%1
Induced 10-16% of Trend & Restraint Volumes
1. Capacity (vph/1ane/one way) 1500 1750 1750 1750 1750
2. Trend Volume (Year 1 3%1
2% after) 1500 1545 1576 1608 1640
3. Restraint (-20% of Base Year) -300 -300 -300 -300
4. Total 1500 1245 1276 1308 1340
5. Induced Volume (10-12-14-16%) 0 128 157 188
6. Total 1500 1245 1404 1465 1528
7. Volume to Capacity Ratio 1.00 .71 .80 .84 .87
8. Speed (mph) 15 25 23 21 20
1. From Highway Capacity Manual. 1965. as explained in text.
1750
1673
-300
1373
220
1593
.91
19
Assumed
Assumed
2~1o of 1500
Lines 2 + 3
Line 4 x (10-16%)
Line 4 + Line 5
Line 6 .:. Line 1
Interpoiation1
t:1
I
'-'
o
-------
Table D-4
ILLUSTRATIVE IMPACT OF TRAFFIC FLOW TECHNIQUES AND
MOTOR VEHICLE RESTRAINTS ON EMISSIONS
F act 0 r s
Sou r c e
Base Year
Year 1
Year 2
Year 3
Year 4
Year 5
Case 4:
Double Price of Parking for 20% Vehicle Reduction/Trend 3% and 2%/
Induced 10-16% of Trend & Restraint Volumes
1. Volume (vph/lane/one way)
2. Volume Increase over
Base Year (%)
3. Speed (mph)
4. Emission Factors
5. Change in Emission Factors
over Base Year (%)
~. Net Emissions Tradeoff (%)
1500 1245 1404 1465 1528
-17 -6 -2 2
15 25 23 21 20
1.00 .67 .73 .80 .83
-33 -27 -20 -17
-44 -32 -22 -15
1593
Table D-3, Line 6
6
19
.87
Table D-3, Line 8
McGraw. Duprey1
t:'
I
......
......
-13
-8
(Line 1 x Line 4)-1500
1500 x 1.00
1.
EPA data as explained in text, but with emission factor in base year at 15 miles per hour adjusted to equal 1.00.
-------
A P PEN D I X
E
ESTIMATING EMISSION REDUCTIONS FROM
PUBLIC TRANSPORT IMPROVEMENTS
As indicated in Chapter 5, public transport improvements alone
hold out little promise for major modal diversions, much less a reduc-
tion in motor vehicle emissions. Our best judgment is that even ex-
tensive improvements would be unlikely to reduce vehicle miles traveledl
(and hence emissions) by more than 5 percent in any major metropolitan area.
For a number of reasons (see below), the Philadelphia Lindenwold
Rapid Transit line probably represents the best commuter rail service
this country has to offer.
Accordingly, the Lindenwold line provides
a good indication of the maximum feasible emission reductions which would
be possible from public transport improvements.
In the following we indicate how the Lindenwold line has combined
speed, convenience and comfort at a moderate cost with an agressively
marketed transit service aimed at meeting the competition of the auto-
mobile.
We conclude, however, that although the line has obviously made
its mark
on improving suburban rapid rail service, its impact on re-
ducing motor vehicle traffic (and concomitant emissions) is less evident
and more difficult to measure.
A reduction in motor vehicle traffic
directly attributable to the Lindenwold line has not occurred, at least
as reflected in available data.
1. Reference is particularly to vehicle miles traveled by light duty
motor vehicles (e.g., the private passenger car).
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E-2
The Philadelphia-Lindenwold Rapid Transit Line
Since February 1969, the Philadelphia-Lindenwold line has
provided high speed access to the commercial centers of Camden and
Philadelphia for commuters from the densely populated suburbs in
1
South New Jersey.
This construction of a new rail rapid system
(accomplished in three years at a total cost of $92 million) offered
an opportunity to include a package of new design and operational
features not so completely available in other D.S.transit systems.
The operating agency, the Port Authority Transit Corporation (PATCO).
2
a wholly-owned subsidiary of the Delaware River Port Authority,
maintains an attitude of concern for customer satisfaction.
For
these reasons, the Philadelphia-Lindenwold line probably represents
the best commuter rail service the country has to offer.
Speed,
convenience and comfort at a moderate cost have been merged into an
aggressively and successfully marketed transit service.
During peak hours, a train appears every four minutes.
During
off-peak periods, service is provided at least every 10 minutes.
There never is a last train to catch; service continues around the
1. The 14.5 mile line extends from Lindenwold, N.J., to Camden over
the Ben Franklin Bridge to Philadelphia.
2. The Delaware River Port Authority (DRPA) utilizing bridge toll
profits from two Delaware River crossings, as well as new bond issues,
financed and constructed the new line. This diversion of funds from
automobile traffic to the construction of a mass transit facility
represents one of the first such occurrences in the country.
-------
E-3
clock.
The present one-way maximum 60t farel and the 22-minute ride2
(over a 14.5 mile line) makes the service highly competitive with auto-
mobile time and cost.
The average 40 mph speed (maximum speed reached
is 75 mph) betters the 30-35 mph on adjacent highways.
The automobile
cost (out-of-pocket) for the trip in 1970 totaled $2.80, including
3
parking and tolls.
The fully automated service includes fare collection and train
operation.
Automatic ticket vending machines provide passengers with
tickets that electronic sensors scan at station gates which allow
entry and exit.
At the exit gate, sensors verify the ticket's des tina-
tion with the exiting station, deduct a trip from multiple ride passes,
or capture one-trip tickets.
Stations are unattended but under television
monitoring from central control.
Passengers having difficulty negotiating
station gates are automatically directed to a special telephone for com-
munication with central control.
Television surveillance at all 12 stations is also maintained for
security purposes.
A public address system is also available to the TV
monitor for each and ~very station and platform.
1. This maximum 60t one-way fare (which has been maintained for three years)
compares with a $1.20 fare in 1970 on the Long Island Railroad for the same
distance but certainly not the same service. PATCO made application to the
ICC for a 22 percent fare increase with a ruling expected by March 1972.
2.
Express trains make the trip in 19 minutes.
3. Tolls on the two Delaware bridges between Philadelphia and New Jersey
(the Ben Frahklin and Walt Whitman Bridges) were increased in mid-1968
from 25~ to 50~ for single rides. Commutation tickets increased from 20~
to 25~.
-------
E-4
One attendant rides each train to open and close train doors.
Otherwise, the train's progress is under automatic train control which
programs its speed, acceleration and deceleration through WABCO continu-
ous coded cab signals.
If an emergency dictates. trains can be operated
manually.
Seventy-five new air-conditioned stainless steel' cars are designed
for passenger comfort with an unusually high ratio of seats (80) to stand-
ing capacity (40). Seats are wide, high-backed, and designed for long dis-
tance riding.
Attractive station interiors are also climate-controlled
(heated and air-conditioned).
Convenient access is provided, with sta-
tion location at major road connections and intersections and the availa-
bility of 8,900 station parking spaces, some free.
Schedules are adhered
to with a customary 99 percent rating for on-time performance.
Graffi ti
disappear when stations are cleaned six nights weekly.
Trains are swept
nightly and thoroughly cleaned twice weekly.
In short, all aspects of the
line's design and operation have been directed toward consumer acceptance
and meeting the competition of the automobile.
Public response to the new Philadelphia-Lindenwold service was
imm~diate acceptance.
Initially, dailyvoiumes of 12,000 to 15,000 riders
were expected.
Yet. the average daily ridership in the first week or
operation was 16,200, with 17,300 in the second week.
A steady increase
has resulted in a daily ridership of about 36,000 passengers in February
1972 .
Table E-l summarizes monthly patronage for all stations since the
inception of service in January 1969.
Based on existing trends, passenger
volumes may be expected to range between 800,000 and 900,000 a m~:mth by
the end of 1972.
However, the data also suggest
some stabilization of
passenger volumes at these levels.
-------
E-S
Table E-l
PHILADELPHIA-LINDENWOLD RAPID TRANSIT
Monthly Patronage-Passengers
January 4, 1969 - September 1971
Month 1969 1970 1971
January 84,031 689,959 757,844
February 226,968 634,173 721,001
March 477,966 711,000 805,419
April 507,026 720,958 773,041
May 522,728 679,180 738,017
June 535,650 706,064 780,191
July 555,273 706,750 729,038
August 556,930 687,321 757,394
September 605,311 725,862 786,240
October 684,640 794,005
November 626,092 757,277
December 722,943 843,540
Source: Port Authority Transit Corporation of Pennsylvania and
New Jersey, Camden, New Jersey.
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E-6
Despite the growth in patronage, the forecast ridership has
. 1
not been ach1eved.
A consultant's projected annual volumes of 11.1,
2
16.2, and 16.9 million for 1969, 1970, and 1971, respectively, did not
materialize.
Table E-2 compares the consultant's average weekday fore-
cast for individual stations with actual experiences and confirms the gap
between forecast traffic and experience.
However, actual annual volumes
have been increasing at 6.1, 8.6, and 9.4 million for the same years and
the ridership for 1972 is expected to be about 10 million.
As might be expected, the line has not proved to be the money-
maker or break-even operation that was anticipated (although the auto-
mated operation was specifically directed to eliminate many labor in-
tensive costs of rail operation).
However, the deficit operation has
practically disappeared.
Out-of-pocket operating losses of $700,000 in
1969 and $147,000 in 1970 were drastically reduced to only $6,722 in
1971.3
Lack of a feeder bus service has been blamed for this inability
to achieve anticipated growth.
However, the Trenton-Philadelphia Coach
Company which has been servicing the Haddonfie1d station since September 1971
only carries 100 passengers each way daily.
Some observers believe that
1. 1he consultant (using 1960 data) assumed continuing economic activity, and
did not foresee later economic downturns. The Camden area in particular has
been severely depressed economically. Expansion that was predicted for cer-
tain business activities did not occur and thus a projected heavy eastbound
traffic between Philadelphia and Camden never developed.
It is also believed that public fear about increasing crime and van-
dalism in the CBD has reduced public transit trips. Fare increases on con-
necting lines of SEPTA and feeder bus services (also assumed by the consultant)
which were not initiated probably further reduced ridership potential.
2. Telephone communication with J. W. Vigrass, Supervisor, Traffic and Plan-
ning, Port Authority Transit Corporation, Camden, New Jersey, February 14, 1971.
3.
Ibid.
-------
E-7
Tab~e E.2
PHlLADELPHIA-LINDENWOLD RAPID T~NSIT LINE
Forecast versus Actual Traffic
Average Week-day
Entering Passengers
Actual Week-day
Consultant's Average Week Percent of
Station Forecas t] Ending 9/17/71 Forecast
Lindenwold 3,220 4,069 126.42
Ashland 1,240 2
2,307 186.0
3
Iladdonfield 6,425 2,997 46.6
Westmont 2,575 2,041 79.3
3
Collingswood 4,225 1,834 43.4
Ferry Ave.-Camden 2,950 2,739 3,4
92.8
Broadway - Camden 7,345 1,567 21. 34
4
City Hall -Camden 3,170 2,572 81.1
5
8th-Market-Pnila. 14,585 6,408 43.9
9-10-Locust 1,025 600 58.5
12-13-Locust 3,960 2,437 61.5
6
15-16-Locust 3,010 5,608 186.3
Total 53,730 35,177 65.5
1. Consultant's forecast ~repared in late 1968 subject to limitations
noted in text.
2. Additional parking space provided after start of operation.
3. Feeder bus services not operating. No coordination between buses and PATCO.
4. Two major firms in Camden shut down, eliminating more than 6,000 jobs.
5. Due to SEPTA higher connecting fares and public fear of shopping in CBD, this
station has not matched estimated traffic.
6. Area experiencing major office building construction and improved shopping area
Source: Port Authority Transit Corporation of Pennsylvania and New Jersey,
Camden, New Jersey.
-------
E-8
conventional bus services can never be successful in an area as sparsely
populated as that adjacent to the Haddonfie1d and other stations.
On
February 19. 1972 the long awaited demand-actuated bus demonstration ser-
vice was inaugurated at the Haddonfie1d station.
The New Jersey State
Department of Transportation and the Urban Mass Transportation Adminis-
tration are aoint1y funding this demonstration which will provide door-
to-door service for commuters to the Lindenwold line.
Another proposed
feeder service at four stations would engage a private bus operator under
a service contract to the State Department of Transportation.
This pro-
posed service is awaiting the Governor's approval.
The implications. for
commuter rail service nationwide, of establishing such a precedent arrange-
ment, will probably delay this approval until detailed study has been com-
p1eted.
Although forecasts have not been realized, optimism prevails.
The
Delaware River Port Authority is seriously studying an extended three-
prong system initially proposed by its consultants 15 years ago.
These
plans would more than triple the present track mileage.
In 1971, the
New Jersey Legislature endorsed the Phi1ade1phia-Lindenwo1d line by author-
izing extension to other New Jersey communities.
The Port Authority which constructed the line without federal, state
or local taxes feels that it has provided a service that has proved itself
worthy of federal aid.
In 1971, the DRPA began a study to evaluate traffic
potential for extended service and to delve into the service factors that
might induce more New Jersey suburbanites out of their cars.
Study results
-------
E-9
are expected in mid-1972.
The study was bakced by a ~750,000 grant from
the Vrban Mass Transportation Administration and, presumably, will su?port
a later application for UMTA capital and grant funds.
General Findin~s From Passenger Surveys
While the Phi1ade1phia-Lindenwo1d system has obviously made its
mark on improving suburban rail rapid service, its impact on reducing
highway congestion (and air pollution) is less evident and more difficult
to measure.
During January-April 1970, PATCO conducted on-board surveys at
each of the line's 12 stations.
The survey respon~e represented 90 per-
cent of the daily ridership which at that time was 30,000.
This survey
sbowed that 40 percent of the riders were former motorists (both drivers
and car pOQI riders).
These findings are summarized in Table E-3.
It ,is
maintained by PATCO that this diversion level would include traffic on the
Ben Franklin and Walt Whitman Bridges.
Table E-3
PRIOR TRAVEL MODE OF PATCO RIDERS
January - April 1970
, ,"-\
~,~ :Ji} . (', ()"1
Former Mode
% of Riders
Est. Distribution
of Daily Ridership
Auto Driver/Rider
Bus Rider
Train Rider
Did Not Make Trip
40
36
11
13
12,000
10,800
3,300
3,900
Es t. Hig hway
Vehicle Trips
Not Made
1
10,909
2162
Total
100
30,000
11,125
l.
2.
Based on car occupancy rates of 1.1 persons.
Based on bus capacity of 50 persons.
Source: Former mode by percentage of riders from PATCO 1970 passenger survey.
-------
E-lO
It is interesting to note that a greater. percentage of riders (47 percent)
represented former transit riders of bus and train.
Using a vehicle occupancy rate of 1.1 persons per vehicle, it is pos-
sible to translate the number of former automobile passengers into motor
vehicle trips that are no longer made.
Table E-3 shows this diversion to be
. 1
almost 11,000 tr~ps.
Assuming that this vehicular traffic would have
traveled on the Benjamin Franklin and Walt Whitman Bridges, these possibly
diverted trips represent only 7.6 percent of the average weekday traffic of
143,464 vehicles on both bridges in February 1970.
Furthermore, even this
small percentage of vehicle diversions is an overestimate because it is
based on the assumption that all former auto riders and dri„ers would have
had and used an automobile -- an unlikely situation.
Presumably, the
vehicle-miles saved would also be a small percentage of the total vehicle-
miles traveled.
Bridge Data and Experience
Examination of traffic data for the two Delaware River bridges
appears to confirm the diversion of trips to the Lindenwold line (Table E-4).
Table E-4 indicates that during 1968-1970, traffic volumes declined by
6 percent on the Benjamin Franklin Bridge and 1 percent on the Walt Whitman.
However, no definite cause and effect relationship can be drawn between
the rail rapid transit and reduced vehicular volumes on the two Delaware
River bridges.
To begin with, two major factors operating during this
1. As indicated in Table E-3, bus trips account for but a small fraction
of the total.
-------
E-ll
Table E-4
VEHICLE TP.AFFIC ON TIlE WALT WHITMAN AND BENJAMIN :5'RANKLIN BRIDGES
BETWEEN NEW JERSEY AND PHILADELPHIA
1968 through 1970
(millions)
Bridge and Percentage Change
Vehicle Category 1968 1969 1970 1968 - 1970
68/69 69/70 68/70
BENJAMIN FRANKLIN BRIDGE
Automobiles - Regular 12.867 11.813 11.684 - 8.2 -1.1 -9.2
Commutation 9.757 10.157 9.663 4.1 _/~. 9 .{) . 6
- --
Sub-totals 22.624 21,970 21,347 -2.9 -2.8 -5.6
Buses 851 750 725 -11.1 -4.1 -14.8
Trucks & Misc. 1,129 1.100 1,056 -2.6 -4.0 -6.5
-
Totals 24,603 23,825 23,129 -3.2 -2.9 -6.0
Average Weekday Volumes 70 68 66 -3.0 -3.3 -5.7
WALT WHITMAN BRIDGE
Automobiles - Regular 15,955 14,928 15,140 -6.4 1.4 -5.1
Commutation 12.851 13.538 13,385 5.3 -1.1 4.2
--
Sub-totals 28,806 28.466 28,525 -1.2 0.2 -1.0
Buses 99 81 64 -18.2 -20.9 -35.4
Trucks & Misc. 1,805 1,821 1,827 0.9 0.3 1.2
-
Totals 30,710 30,368 30.416 -1.1 0.2 -1.0
Average Weekday Volumes 84 83 83 -0.8 0.2 -1. 2
Source:
Delaware River Port Authority.
-------
E-12
period could account for the declines in bridge traffic.
First, the
Philadelphia-Camden area has e~perienced extended depressed economic
activity which has resulted in reductions in the number of work trips.
As indicated earlier, this is particularly true for Camden and has
greatly affected Philadelphia to Camden movements.
Second, increaseq
bridge tolls in mid-196B must be considered a strong influence on the
decreased bridge usage.
This toll increase fell more heavily on individ-
ual rides (an increase of 25~ to 50~) than on commutation tickets
(20~ to 25~).
The effect of the bridge toll increases can be seen from the
data for both bridges in the shift, between 1968 and 1969. in automobiles
from the regular individual toll category to the commutation category.
However, automobiles using commutation tickets then declined on both
bridges between 1969 and 1970 (4.9 percent on the Franklin Bridge, and
1.1 percent on the Whitman).
The toll increases may have also encouraged
more car pooling, which would further attenuate the bridge traffic de-
cline such that the decline in vehicular traffic may not represent a
similar decline in numbers of people.
The disproportionate declines in bus traffic compared to other
vehicles, shown in Table E-4 (i.e., 14.8 percent on the Franklin Bridge
and 35~4 percent on the Whitman Bridge). may indicate the lower levels
~ . b 1
of economic activity, particularly involving low income JO s, as well
as the 36 percent diversion of former bus riders to the Lindenwold Line.
1. Since generally public transit riders are of lower income levels than
automobile commuters.
-------
E-13
Figures E-1 and E-2 show hourly traffic volumes for representative
months by direction on the Franklin Bridge for the years 1968 and 1970
on a typical week-day -- Wednesday.
In the westbound direction on the
Franklin Bridge, it was significant that in three out of the four months
reviewed, the 1970 traffic peak was higher than the pre-Lindenwo1d 1968
levels.
Since Lindenwold operates on a 24-hour basis some relationship
might be considered in slightly lower 1970 values for nighttime and base
day volumes.
However, the actual differences observed could readily be
caused by decreased economic activity.
The eastbound graph shows a lower peak A.N. usage in 1970 for
Philadelphia citizens commuting to Ne\v Jersey.
The P.M. westbound peak
traffic to Philadelphia (presumably the reverse flow) also shows a
slight decline in two of the four months with the P.M. peak less concen-
trated, that is spread over a longer time period.
Again, depressed econo-
mic activity in Camden may have been the reason for these declines.
The impact of the Philadelphia-Lindenwold line on reducing vehicle-
miles and air pollution levels is difficult to define.
Examination of
the bridge traffic data during 1968-1970 does not reveal any significant
shifts in overall traffic patterns, other than the declines (already dis-
cussed) that would not necessarily be related to the opening of the Linden-
wold line.
For example, Figure E-3 shows a 12-month moving average for
traffic volumes on the two bridges from 1967 through 1971.
It is readily
apparent that there has been a dec1in~ in traffic which pre-dates the open-
ing of the Lindenwold line and is probably related to factors other t~an
the new transit service.
The data in Figure E-4 show the annual traffic
volumes for the period 1960-70 and confirm
that the
gradual declines shown
-------
E-14
in Figure E-3 began before the start of the Lindenwold service.
In fact,
these traffic declines appear to have started before the increase in toll
rates in 1968.
This is clearly shown in Table E-5 and Figure E-l which show
the annual percentage change in traffic from 1960 through 1970.
'l11e data
in Table E-5 and Figure E-l indicate that in terms of rate of change, traffic on
the bridges started to decline between 1966 and 1967.
In those years, traf-
fic increased by only 0.3 percent in contrast to the 4-5 percent annual
increases for earlier years.
This again suggests economic and other forces
operating other than the 1968 toll rate increase and the start of the Linden-
wold service in 1969.
Table 5
VEHICLE TRAFFIC ON THE WALT WHITMAN AND BENJAMIN F~~KLIN BRIDGES BETWEEN
NEW JERSEY AND PHILADELPHIA: ANNUAL VOLUMES AND PERCENTAGE CHANGE
1960-1970
Year
Traffic
Volume
(thousands)
Percentage
Change From
Previous Year
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
43,925
44,998
47,073
48,254
50,208
52,850
55,483
55,631
55,313
54,193
53,545
2.4
4.6
2.5
4.0
5.3
5.0
0.3
-0.6
-2.0
-1. 2
Source:
Delaware River Port Authority
-------
E-15
Figure E-l
WESTBOUND VEHICLE FLOW ON BENJAMIN FRANKLIN BRIDGE, 1968 and 1970,
Hourly Volumes, Average Wednesday, for Selected Months
Thousands
of Vehicles
5
Feb. .
o
- --
4
8
12
16
20
24
H'Jurs
5
May
......-~-.......
,--.....-- -~.....
/' ,
0
4 8 12 16 20 24 Hou rs
5
Aug. .
-.,r-....---e--....
/- --
- --- ....
0 --
4 8 12 16 20 24 Hours
5
Nov.
0 ----
4 8 12 16 20 24 H'Jurs
-----
-1968
1970
Source:
Delaware River Port Authority
-------
E-16
Fi~ure E-2
EASTBOUND VEHICLE FLOW ON BENJAMIN FRANKLIN BRIDGE, 1968 and 1970,
Hourly Volumes, Average Wednesday, for Selected Montns
---"
Thousands
of Vehicles
5
o
:---~
1"
".- -,
~".
,- -~ .
~
---' \,,-,,.
#
~-~
Feb. .
-
-
4
8
12
16
20
24 Hours
5
o
..,
'-
-- ~
May
4
8
12
16
20
24 Hours
5
",.........
"~ ......-
-"""--...--e
Aug. .
.II'
'"
o
4
8
12
16
20
24 Hours
5
Nov.
0 --
4
... -
,
\
"---r--',
.~
8
12
16
20
24 Hours
-----
-1968
1970
Source:
Delaware River Port Authority
-------
RECORDED MONTHLY TRAFFIC VOLUMES ON THE BENJAMIN FRANKLIN AND WALT WHITMAN BRIDGE
BETWEEN NEW JERSEY AND PHILADELPHIA 1967-1971
JF'MAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASOND
1967 1968 1969 1970
1971
Delaware River Port Authority
-------
mm
jtirtji:
l
'iii
ITT
iiii
Łt
::m
inrrrr
MIT"!
WP„
ON
mi
.±!.7it}
f-1
.II'
.i-!-
itrt
:r:
ttitf
rrhil
-
tf
u :nn
'ill
HtH
uiiJtt
:1CW>.:.T]
'6
sars_
-------
E-19
Figure E-5
ANNUAL PERCENTAGE CHANGE IN TRAFFIC VOLUMES
THE WALT WHITMAN AND BENJAMIN FRANKLIN BRIDGES
NEW JERSEY & PHILADELPHIA
1960-1970
ON
BETWEEN
6.0
6.0
4.5
- 4.5
'"d
ro
'i
3.0 3.0 (")
ro
~
...,
~
()Q
ro
>,
~ CJ
,~
C\I ;::I"
=' ~
!:: 1.5 1.5 ~
~ ()Q
ro
QJ
bD >
!::
C\I ~
'~ ~
u ~
~
f-'
o 0 f-'
QJ '<
bD
C\I
, ~
!::
QJ
, U
, 1-1
, QJ
il<
-1.5 -1. 5
-3.0
60-61
-3.0
61-62 62-63
63-64
64-65
65-66
66-67
67-68
68-69
69-70
Years
Source: Delaware River Port Authority
-------
Ł-20
This is not to belittle the value of the service but rather to in-
dicate that a reduction in vehicles directly attributable to the Linden-
wold service has not occurred (at least as reflected in the data for the
two bridges).
Interestingly. bus traffic declined at a much higher rate
than other vehicle categories, particularly on the Whitman Bridge which
is three miles south of the Lindenwold crossing on the Franklin Bridge.
Part of this decline ~ay be related to the fact that a large proportion
of riders on the line were diverted from transit buses.
Another consideration of some importance is the fact that the
initial diversion from autos does not appear to have continued or in-
creased.
Some PAT CO officials believe that a 6,000 increase in passengers
since the early 1970 daily ridership of 30,000 represents new residents
attracted to South New Jersey suburbs by the availability of the Linden-
wold Line.
Apparent increased real estate activity has been occuring
in the areas of the Ashland and Lindenwold stations, and as shown in Table E-2,
thesp two stations are among the three on the Lindenwold Line that have
met the forecast ridership.
In summary, the impact of the line on highway traffic and air pol-
lution is difficult to measure because of the unknown effect of increased
bridge tolls and general economic depression of the area.
The Lindenwold
line has also been affected by the area's reduced economic activity in that its
projected traffic has not been realized.
While the initial 40 percent auto-
mobile diversion that appeared on passenger surveys on the rapid transit line
remains, this diversion has not grown and appears to be related only to the
initial impact of the line.
If it were translated into vehicle trips not made
or vehicle-miles not driven, the effect on air pollution levels would be negligible,
-------
A P PEN D I X
F
ESTIMATING EMISSION REDUCTIONS FROM MOTOR VEHICLE RESTRAINTS
Elsewhere (Chapter 6 '~aximum Feasible Emission Reduction"),
we have offered our best judgments about the reduction in motor vehicle
traffic which might result from higher parking ratesl (as much as quad-
rupled) in Washington, D. C.
In this appendix we review the evidence
upon which these judgments are based and indicate some of the difficulties
in drawing conclusions from existing data and modal split analyses.
In
the following discussion of motor vehicle restraints we assume that
public transport will be importantly improved in order to serve as a
substitute for motor vehicle trips.
Without these improvements, diverted
motorists will be unlikely to use public transport, and access for work
and other trip purposes would be seriously constrained, with profound
social and economic consequences.
The emission reduction potential of motor vehicle restraints is a
function of the severity of those restraints.
Obviously, if the number
of parking spaces were significantly reduced in downtown areas, motor
vehicle miles traveled into and around these areas (and resulting emissions)
could be significantly reduced.
Conversion of major portions of any central
city into vehicle-free zones could have an even more dramatic effect.
However, complete bans on motor vehicle use in major portions of any
metropolitan area are clearly not feasible by 1977.
In addition to the
1. Controls over parking may be considered as a "surrogate variable"
for motor vehicle restraints.
-------
"i
F-2
prac~ical problems (e.g., providing alternative transportation) the
political opposition (e.g., from automobile owners' associations, down-
town merchants) would be enormous.
Furthermore, it is difficult at this
time to see where strong political support for such complete exclusion
WOuld come from.
Assuming a more modest program of motor vehicle restraints, how-
ever,
what emission reductions might be reasonably expected?
Unfortunately,
present knowledge does not permit a definite answer.
No systematic study
has been made of the price elasticity of motor vehicle use,l although
there are some indicative observations.
For instance, parking prices set
at market rates have risen steadily the past two decades in cities such as
Washington, D. C.
During this time, traffic in Washington, D.C. has also
increased steadily and more parking spaces have become available (as park-
ing continues to be a profitable business).
Monthly parking contracts
in densely developed areas of the District of Columbia are now up to $30
to $35 on open lots and $40 to $45 in office buildings.
In effect, the
daily rate is between $1.50 and $2.00.
The so-called "daily rates" range
between $2.00 and $3.00 for the same areas.
At present, no systematic
price change -- motorist response data are available for parking charges,
1. Price elasticity here refers to the percentage
use accompanying a change in the cost of using the
investment, operating or time cost).
change in motor vehicle
motor vehicle (either
-------
F-3
but at the gradual rate prices have risen, it is clear that there has
been no reduction in traffic.1
The World Bank, which is also strongly interested in such matters,
has recently published a study of road pricing which develops some elas-
2
ticity data for use in congestion pricing plans. The data presented
were derived from observations made by the Road Research Laboratory in
the United Kingdom, mostly in the London area.
Interpretation of these
data indicates that imposing road pricing rates of lOt to 20t per vehicle-
3
mile would reduce traffic volumes by 20 to 30 percent.
The resulting
road pricing costs for typical commuting trips in the London area are
shown in Table F-l.
For a number of reasons, however, the United States response to
such increases would be much less than that for England.
In our judgment,
the rate of 20t per mile (which for the average trip in Washington, D.C.
would be about $4.00 or a total charge of $88.00 a month) would have a
1. However, incomes have also been on the rise so that "real" increases
in parking rates may be much lower than they seem.
While attempting ~o determine the price elasticity of motor vehicle
use, we contacted the International Bridge, Tunnel and Turnpike Association.
None of the Association's members had made specific elasticity studies.
They are strongly disposed not to reduce toll rates, and in some cases
have doubled them. They uniformly report that there was an immediate drop
in traffic volume,which recovered in six months or less, at which time
previous traffic road rates were resumed.
2. See A. A. Walters, The Economics of Road User Charges, International
Bank for Reconstruction and Development, Occasional Paper No.5: 1968.
Unfortunately, for purposes here, the basic objective of this study (to
examine revenue raising measures by road pricing of congested traffic for
purposes of building additional road capacity) was significantly different
from that of air pollution control.
3.
Ibid., pp. 178, 200.
-------
F-4
Table F-1
ROAD PRICING RATES FOR TYPICAL COMMUTING TRIPS IN LONDON AREA
Length of Commuter Trip Total Cost at Different Ratesl
lOtjmi. 20tjmi.
4 $ .80 $1.60
6 1. 20 2.40
10 2.00 4.00
15 3.00 6.00
Source: A. A. Walters, The Economics of Road User Charges, International
Bank for Reconstruction and Development, Occasional Paper No.5, 1968.
1.
Two-way round trip miles; all costs converted to U.S. dollars.
maximum diversion effect of 15 to 20 percent, and would have to be accom-
panied by important public transport improvements in order to be imp1ement-
able.
This type of charge is of some interest because the price is ad-
justed to trip length, whereas a proposed parking charge would be a flat
rate (irrespective of trip length) and would therefore be regressive on
" .'
those using cars for relatively short distances.
From a transportation
point of view, this does not seem objectionable, as it could be assumed
1
that short distances may be more easily made on public transport.
At
least in areas such as Los Angeles and Washington, D. C., it can also be
argued that drivers coming the longest distances are usually the most
1. From an air pollution control point of view, however, it may be
desirable to discourage long trips.
-------
F-5
poorly served by public transport.
This would not be true where well
developed commuter railroads are in operation (e.g., New York City, Chicago,
Philadelphia).
Another possible source of elasticity data are the modal split models
used by transportation planners.
Setting aside details of methodology,
the major purpose of modal split analysis is to estimate the proportion
of person trips that will be made by a public transport and the private
1
automobile.
A number of variables are examined related to one another
in order to measure the impact of changes in these variables on transit
ridership.
In general, key variables include income, vehicle operating
costs, time differentials between transit and motor vehicles, vehicle
ownership, vehicle occupancy and parking costs.
Using the total trip estimates projected from comprehensive trans-
portation studies (usually available for major metropolitan areas) person
trips are apportioned among modes.
Typically, however, the modal split
models do ~ indicate whether diversions to transit will result in re-
duced motor vehicle use.
For example, a modal split model may indicate
that with the construction of a new rapid transit system, approximately
15 percent of total trips would travel on the new system.
Assuming that
15 percent represented about 10000 trips diverted into transit, there is
usually no indication what would happen to motor vehicle use (i.e., will
it increase, decrease or remain the same).
1. The analysis is usually for a 25 hour period as well as for peak hours
(a.m. and p.m.) for all trip purposes.
-------
F-6
Increased transit trips may not necessarily reduce motor vehicle
use for several reasons.
For one thing, part of the ridership may come
from present bus riders, who divert to a more convenient transit.
Another
part of the ridership may come from motor vehicle riders (distinct from
drivers) who are in a car pool and find the transit less costly and equally
or more convenient (there is some evidence that vehicle occupancy rates
decline with improved transit).
Finally, some trip makers (perhaps pre-
sently on transit) may become automobile drivers (i.e., enter into the
traffic stream) as they discover that congestion has been reduced some-
what.
And, in the medium and long term, assuming auto traffic continues
to grow, the level of traffic will return and eventually surpass what
levels had been prior to implementation of the new transit system.
By no means is it suggested that there will be no reduction of
motor vehicle use associated with public transport improvements.
How-
ever,
these reductions will probably be offset by the forces just des-
cribed although there is little available data which permit a definitive
evaluation of the net change.
In one case where data are available (i.e.,
for the Bay Area Rapid Transit [BART] system in the San Francisco area),
estimates have been made of the reductions in motor vehicle use for 1975
projected traffic, both in terms of vehicle miles traveled and trips.
These estimates of the impact of BART indicate that "in the four counties
of Alameda, Cortra Costa, San Francisco and San Mateo, the trips diverted
from motor vehicles to BART by 1975 will reduce the vehicle miles of
-------
F-7
1
travel per day by 2.1 percent."
Similar estimates for the San Francisco
and East Bay areas indicate that by 1975 there would be reductions of 3.1
. 2
and 1.5 percent respect1vely.
Estimates were also made for the San Fran-
cisco-Oakland Bay Bridge, and even along this important line-haul corridor
where transit is most competitive, "the person trips diverted from motor
vehicles using the Bay Bridge to BART would represent a reduction in total
vehicle miles per day of 8.1 percent by the year 1975.,,3
Another case in point concerning modal split procedure relates to
the model developed in the 1960's for application to Washington, D. C.
In
the course of developing the model, an attempt was made to assess the sen-
sitivity of the procedure (i.e., its ability to reflect changes in input
variables).
One sensitivity test involved doubling parking costs in the
zero sector zones ( which approximate the downtown CBD) of Washington, D.C.
Results from this test are shown in Table F-2.
Unfortunately, there is very little empirical data on which to es-
tablish the cause and effect relationships among the variables used in this
(or any other modal split)
model.
In many cases, the models merely reflect
1. California Air Resources Board, "Air Quality Control Plan" (preliminary
draft, November 15, 1971), p. 15. In connection with this estimate, it
should be noted that the BART system only includes the four counties above.
2.
Ibid., especially see chapter on "Impact of Mass Transit."
3.
Ibid., p. 12.
-------
F-8
Table F-2
SENSITIVITY OF WASHINGTON, D. C. MODAL SPLIT MODEL TO DOUBLING
PARKING PRICES IN DOWNTOWN OF WASHINGTON, D. C.
Basel Doubled Parking Costs
Total person trips 465,825 465,825
Number via transit 108,169 115,972
Percent diversion 0.2322 0.2490
Percent change +7.2
Person trips to CBD 148,390 148,390
Number via transit 85,952 92,609
Percent diversion 0.5794 0.6241
Percent change +7.7
Non-CBD oriented person trips 317.435 317.435
Number via transit 22,217
Percent diversion 0.0700 0.0700
Percent change
Source: Arthur B. Sosslau, Kevin E. Heanue, and Arthur J. Balek,
"Evaluation of a New Modal Split Procedure," (paper prepared by the
Federal Highway Administration for the Highway Research Board Committee
on Origin and Destination).
1. National Capital Transportation Agency traffic assignment model,
using 1955 origin and destination data, a.m. peak traffic hours, working
trips only.
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F-9
the working assumptions of transportation analysts, and cause and effect
relationships are imperfectly understood.
As a result, modal split
models are useful only within narrow ranges and are heavily weighted
upon past experience.
They do not help when major policy variables are
being altered (e.g., a significant reduction in motor vehicles entering
the CBD).
Limitation of the modal split model to relationships within rela-
tively narrow ranges was noted in the following caution taken from the
above-cited article prepared by the Federal Highway Administration for
the Highway Research Board:
The modal split procedure was sensitive to
changes in the cost ratio only in a very
limited range. From the drastic changes
in the cost ratio variable -- double tran-
sit figures to double parking costs -- the
number of estimated riders ranged from
only 99,752 to 115,972.1
Another source of modal split data can be found in an analysis of
the Minneapolis-St. Paul area in the late 1950's.
The parking cost
variable used in the modal split analysis tends to confirm the inelasti-
city suggested above with regard to the Washington, D. C. model.
Based
on a 1958 survey of origins and destinations and parking, the model related
parking costs per hour to transit usage in the two CBDs.2
The relationship
1. Arthur B. Sosslau, Kevin E. Heanue, and Arthur J. Balek, "Evaluation
of a New Modal Split Procedure," (paper prepared by the Federal Highway
Administration for the Highway Research Board Committee on Origin and
Destination). This is not to suggest an error, but rather that demand is
relatively inelastic.
2. u.S. Department of Commerce, Bureau of Public Roads, Office of Planning,
Modal Split, Documentation of Nine Methods for Estimating Transit Usage
(Washington, D.C.: Government Printing Office, 1966), see especially
pp. 96 and 100.
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F-10
is shown in Figure F-1.
The average amounts actually spent were also
calculated for 3-hour and 9-hour parking periods.
The CBD averages
were 5-10~ for a three-hour period (about 40~-80~ for an 8-hour day)
and slightly less for a 9-hour period.
The average per hour cost in 1958
has also been shown in Figure F-1.
At the 1958 average level of parking cost, transit usage was in
the range o~ about 30 percent.
If parking prices were doubled (to
80~-$1.60 a day), and the functional relationship in Figure F-l is correct,
transit usage would have risen to about 45 percent -- a relatively small
increase, when measured against the number of motor vehicle trips which
might have been reduced.
Furthermore, as already noted, many of these trips
would not result in a 1:1 reduction in motor vehicle use.
It would also
appear from Figure F-l that achieving 80 percent transit llsage in
Minneapolis-St. Paul in 1958 would have required quadrupling parking
prices.
A modal split model for the planning of the Baltimore Rapid Transit
System included a feature not typically found in modal split models, namely
the testing of different levels of parking charges in the model.l
The
parking charges tested ranged from 4~ per hour (approximately 30 to 35f
a day) to 30~ per hour (approximately $2.50 to $3.00 per day).
These
rates were applied to three categories of trips, and the curves were pro-
duced by the model for the full range of travel time ratios (i.e., the
difference between the door-to-door time for motor vehicles in transit).
1. See Alan M. Voorhees & Associates, Inc., A Report on Mode Choice Analysis
for the Baltimore Region, AMV-R-20-l043(921) (McLean, Va.: Alan M. Voorhees
& Associates, Inc., undated).
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F-ll
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F-12
Six income levels were used from "under $2,500 per annum" to "over $10,000
per annum."
(See Table F-3 and Figure F-2
)
Unfortunately, the resulting groups of curves are not uniform and
do not lend themselves to averaging.
For trips between house and work
where transit and auto travel times are the same (no difference implies
a relatively high quality of transit service), the curves indicate that
after the transit fare rises above 75 percent of the market, the demand
for auto travel is relatively inelastic at nearly all income levels.
In
other words, it is extremely difficult to shift further motor vehicle users
to transit.
The curves also indicate that in Baltimore the low income
groups already have relatively high transit ridership, so that, for these
income groups, the amount of shifting would be negligible.
Contrariwise,
the highest income group offers greatest diversion potential.
It should
be stressed, however, that the proposal transit system in the Baltimore
model is a high quality six-line rapid rail system which would require
15 years to complete.
For reasons not entirely clear, the Baltimore modal split model
shows the greatest elasticity for the first increment of change in parking
prices, from 0 to 4~ and 5 to 8~ per hour at all income levels but espe-
cially for higher income groups above $5,000 per annum.
This "result"
has not been satisfactorily explained, and is apparently an abberation
of this particular model.
This model did forecast that with a daily
parking cost of $2.50 or higher, all income groups receiving good transit
service (with no travel time differential) would have transit ridership
above 50 percent, ranging from 84 percent for the lowest income groups
down to 53 percent for the highest.
(See Figure F-2.)
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F-13
Table F-3
MODE CHOICE ANALYSIS FOR BALTIMORE - PERCENT TRANSIT TRIPS
FOR VARIOUS PARKING RATES WORK TRIPS
Income Percent Transit Usage at Parking Rate
Group 0-4t./hr. 5 - 8t./hr. 9-29t./hr. 30t+/hr.
Zero Time Differential Between Highway and Transit
1. $0-$2,500 64% 76% 787. 84%
2. $2,501-$5,000 54 72 76 82
3. $4,001-$6,000 40 68 75 78
4. $6,001-$7,000 32 60 68 75
5. $7,001 $10,000 27 52 54 62
6. Over $10,000 18 42 44 53
10 Minute Time Advantage to Transit
1. $0-$2,500 66 78 83 86
2. $2,501-$5,000 59 74 82 85
3. $5,001-$6,000 50 72 79 83
4. $6,001-$7,000 44 68 75 78
5. $7,001-$10,000 38 66 68 70
6. Over $10,000 33 60 62 64
Source: Alan M. Voorhees & Associates, Inc., A Report on Mode Choice Analysis
for the Baltimore Region, AMV-R-20-1043(921) (McLean, Va.: Alan M. Voorhees
& Associates, Inc., undated), Fig. 3-3 through 3-6, pp. 20-23.
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HERTIITTHAI SIT :T1 iE &B\ AHTAGI
-------
F-l5
At the time of the forecast, $2.50 per day was higher than the
average downtown Baltimore parking rate.
Table F-2 shows what an increase
in parking costs from 60f to $2.50 per day (assuming the relationship
shown in Table F-3 and Figure F-2 is correct) would produce for
Baltimorians for whom there are no travel time differences between motor
vehicles and transit (i.e., excellent transit service) and with a lO-minute
time advantage to the auto.
The column showing percentage change in
transit ridership (last column in Table F-4) clearly illustrates the
sensitivity of the upper income groups to changes in the price of parking
and the influence of trip times.
Examination of these and other curves from the Baltimore modal
split study indicates that in the corridors where relatively good transit
service (i.e., frequent schedules and/or express bus lines) is already
in operation, there will be relatively small diversions from autos to
transit, even with a quadrupling of parking costs.
On the other hand,
these data indicate that with a substantial improvement in transit
travel time and a quadrupling in parking costs, relatively large diversions
could be obtained from the upper income groups of drivers.
Unfortunately,
there is no way to weight the Baltimore income groups to develop an
"average."
It must also be pointed out that the Baltimore curves assume
a large rapid transit system.
In most cities without rapid rail, only
close-in residents living near major arterials with multiple bus lines
could ever receive bus transit service that would provide the same elapsed
time as driving.
In sum, the major problem with relying heavily on relationships
provided by calculations with modal split models is that they are
-------
!""'"""
F-l6
Table F-4
SENSITIVITY OF BALTIMORE, MD., MODAL SPLIT MODEL
TO CHANGES IN PARKING PRICES
Income Percent of Home-Work Riders on Transitl
Group 60t/day $2.50/day Diff. '/0 points % Incr.
1. $0-$2.500 p.a. 76% 84 '/0 8 11
2. $2,5Q1-$5,000 72 82 10 14
3. $5.001-$6.000 68 78 10 15
4. $6.001-$7.000 60 75 15 25
5. $7.001-$10,000 52 62 10 19
6. $10.000 and over 42 53 11 26
Percent of Home-Work Riders T . 2
on rans~t
1. $0 $2,500 p.a. 72 78 6 8
2. $2,501-$5,000 67 75 8 12
3. $5.001-$6,000 61 74 13 21
4. $6,001-$7.000 50 70 20 40
5. $7.001-$10.000 38 56 18 47
6. $10.000 and over 28 46 18 64
Source: Alan M. Voorhees & Associates. Inc.. A Report on Mode Choice Analysis
for the Baltimore Region, AMV-R-20-1043(921) (McLean. Va.: Alan M. Voorhees
& Associates, Inc.. undated).
1.
Assumes no travel time differential between motor vehicle and transit.
2.
Assumes 10 percent travel time differential in favor of motor vehicles.
-------
F-fl
based upon limited data for determining driver reactions to cost differen-
tial factors.
Many assumptions (amounting to judgment) have been used
as inputs for the models.
While the Baltimore model provides data which
are encouraging from an air pollution control standpoint, it is calibrated
to a compact industrial city with very good bus transit service in the
past and relatively low incomes.
The direct application of these untested
modal split model-derived ratios must be approached with considerable caution.
Nevertheless, on the basis of available evidence our best judg-
ment is that improvements in public transport which are feasible within
five years (i.e., by 1977) will not by themselves reduce motor vehicle
traffic by more than 5 percent.
Furthermore, there is no evidence to
indicate that any permanent reduction in traffic would be possible with-
out motor vehicle restraints.
The response to changes in parking rates (taken here a-s a surrogate
for motor vehicle restraints) is likely to differ depending on whether
motorists have free or subsidized parking or whether they already pay
the going rate.
Evidence suggests that for those paying the full rate,
doubling parking rates in the CBD (say. from $30 to $40 per month in the
core of Washington, D. C. to $60 or $80) would have a minor effect,
perhaps not to exceed a 5 percent reduction in motor vehicle traffic.
For the market which now pays the current rates, most of the marginal
users have already been "squeezed out."
k. 1
If higher par ~ng rates were imposed (presumably through taxes)
00 employees receiving full parking space or on the employers now
1. Say, an ":Jvernight" increase from $0.00 to $60 to $80 per month for
all workers parking in the CBD.
-------
F-18
furnishing it, a reduction by 15 to 20 percent in motor vehicle traffic
might be possible.
There are undoubtedly a great many more marginal
drivers among those in free parking spaces than among those in already
costly space.
This consideration also implies that in any strategy to
control parking, the first effort should be to eliminate all free spaces
and to greatly increase the charge for meter parking, at least to 25~
per hour.
Evidence from the Baltimore modal split analysis suggests that
the middle to high income suburbanite commuters are likely to be the most
responsive to changes in the parking rates, if good public transport is
available for the work trip.
Vehicle occupancy is also likely to ris~
(which in itself would tend to reduce vehicle miles traveled).
Finally, if under a comprehensive parking control program, a
parking space tax of $60 to $80 for all spaces were applied in the
CBD of Washington, D.C. (and comparable rates in other cities), and if
all on-street parking were eliminated (including most of the illegal
parking) there might be an overall reduction in motor vehicle traffic
of perhaps 20 percent or at the most 25 percent.
Again, all this assumes
that public transport would be importantly improved to provide an a1ter-
nate means of making trips.
Such a comprehensive parking control program
for Washington, D.C. would imply a tripling or quadrupling of existing
rates to $90 to $120 per month for existing pay parking and $60 to $80
for existing free parking.
These levels would appear to be the upper
limit of practical action at present.
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G...l
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-------
G-3
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G-4
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G~5
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G-6
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G-7
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G-8
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-------
G-10
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G-12
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*U. S. GOVERNMENT PRINTING OFFICE: 1978-746-767/4139
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