APTD-1363
PREDICTION
OF THE EFFECTS
OF TRANSPORTATION CONTROLS
ON AIR QUALITY IN MAJOR
METROPOLITAN
AREAS
s
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
-------
APTD-1363
PREDICTION
OF THE EFFECTS
OF TRANSPORTATION CONTROLS
ON AIR QUALITY IN MAJOR
METROPOLITAN AREAS
Prepared by
TRW Inc.
Transportation $ Environmental Operations
7600 Colshire Drive
McLean, Virginia 22101
Contract No. 68-02-0048
Task Order 6
Project Officer: Gary Hawthorne
Stratergy 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
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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 supplies
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 Techncial
Information Service, 5285 Port Royal Road, Springfield, Virginia 22151.
This report was furnished to the Environmental Protection Agency by TRW,
Inc., McLean, Virginia, in fulfillment of Contract No. 68-02-0048, Task
Order 6. The contents of this report are reproduced herein as received
from the TRW, Inc. The opinions, findings, and conclusions expressed are
those of the author and not necessarily those of the Environmental Protec-
tion Agency.
Office of Air Programs Publication No. APTD-1363
11
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ACKNOWLEDGEMENT
TRW received considerable assistance in the collection and compila-
tion of the data contained in this report. In particular, Mr. Joseph
Revis of the Institute of Public Administration was responsible for the
collection and preliminary interpretation of the traffic information
from each of the six metropolitan areas. Many local and state agencies
supplied data and critical analysis to the study. Continual project
direction and guidance were provided by Mr. Gary Hawthorne of the
Environmental Protection Agency's Land Use Planning Branch.
iii
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TABLE OF CONTENTS
Section Description Page
DISCLAIMER 11
ACKNOWLEDGEMENT Ill
1.0 INTRODUCTION 1-1
2.0 GENERAL METHODOLOGY 2-1
2.1 Summary 2-1
2.2 Transportation Methodology 2-2
2.2.1 General Guidelines 2-2
2.2.2 Specific Approach 2-3
2.3 Mobile Source Pollutant Concentration Program
(MSPC) 2-4
2.3.1 Program Input 2-5
2.3.2 Program Output 2-10
2.4 Strategies Evaluation 2-18
2.4.1 Strategy 1: Inspection and Maintenance 2-18
2.4.2 Strategy 2: Traffic Flow Controls ... 2-19
2.4.3 Strategy 3: Motor Vehicle Restraints . 2-23
3.0 SIX CITY TRANSPORTATION STUDY RESULTS 3-1
3.1 Introduction 3-1
3.2 Metropolitan Area Analysis - Chicago 3-2
3.2.1 Data Base and Methodology 3-2
3.2.2 Summary of Results 3-5
3.3 Metropolitan Area Analysis New York 3-16
3.3.1 Data Base and Methodology 3-16
3.3.2 Summary of Results 3-22
3.4 Metropolitan Area Analysis Denver 3-31
3.4.1 Data Base and Methodology 3-31
3.4.2 Summary of Results 3-33
3.5 Metropolitan Area Analysis - San Francisco . . 3-42
3.5.1 Data Base and Methodology 3-42
3.5.2 Summary of Results 3-47
3.6 Metropolitan Area Analysis - Los Angeles . . . 3-56
3.6.1 Data Base and Methodology 3-56
3.6.2 Summary of Results 3-59
4.0 METROPOLITAN AREA ANALYSIS - WASHINGTON, D. C. . . . 4-1
4.1 Data Base and Methodology 4-1
4.1.1 Transportation Data 4-1
4.1.2 Meteorological Data 4-3
4.1.3 Stationary Sources 4-3
4.2 Summary of Results 4r4
4.2.1 Carbon Monoxide 4-6
4.2.2 Hydrocarbons 4-11
4.2.3 Oxides of Nitrogen 4-14
4.3 Comparison of Calculated Concentrations with
Ambient Measurements 4-17
APPENDIX A-l
iv
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LIST OF TABLES
Table
Number Description Page
2-1 Sample Output for Mobile Source Pollutant
Concentration Program 2-12
2-2 Speed Adjustment Factors 2-21
2-3 Motor Vehicle Restraint Factors 2-30
Chi.l Predicted Maximum Emissions and Concentrations .... 3-6
Chi.2 Annual Emissions (tons/year) for the Area Shown
in Figure Chi.l 3-10
Chi.3 Predicted Maximum Emissions and Concentrations .... 3-11
3.3-1 Speed Adjustment Factors for the New York Region
by Distance From CBD 3-20
N.Y.I Predicted Maximum Emissions and Concentrations
for Carbon Monoxide and Nitrogen Oxides 3-24
N.Y.2 Predicted Maximum Emissions and Concentrations
for Hydrocarbons 3-27
N.Y.3 Annual Emissions (tons/year) for the Area Shown in
Figure N.Y.I 3-28
Den.l Predicted Maximum Emissions and Concentrations
for Carbon Monoxide and Nitrogen Oxides 3-34
Den.2 Predicted Maximum Emissions and Concentrations
for Hydrocarbons 3-38
Den.3 Annual Emissions (tons/year) for the Area Shown in
Figure Den.l 3-40
S.F.I Predicted Maximum Emissions and Concentrations
for Carbon Monoxide and1 Nitrogen Oxides 3-49
S.F.2 Predicted Maximum Emissions and Concentrations
for Hydrocarbons 3-52
S.F.3 Annual Emissions (tons/year) for the Area Shown in
Figure S.F.I 3-53
L.A.I Predicted Maximum Emissions and Concentrations
for Carbon Monoxide and Nitrogen Oxides 3-61
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List of Tables (Continued):
Table
Number Description Page
L.A.2 Predicted Maximum Emissions and Concentrations
for Hydrocarbons 3-65
L.A.3 Annual Emissions (tons/year) for the Area Shown in
Figure L.A.I 3-66
D.C.I Predicted Maximum Emissions and Concentrations
for Carbon Monoxide and Nitrogen Oxides ........ 4-7
D.C.2 Annual Emissions (tons/year) for the Area Shown in
Figure D.C.I 4-10
D.C.3 Predicted Maximum Emissions and Concentrations
for Hydrocarbons 4-12
D.C.4 Washington, D. C., 1968 Ambient and Predicted
Pollutant Concentrations at the CAMP Station 4-18
vi
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LIST OF FIGURES
Figure
Number Description Page
2-1 Scheme for Combining Rectilinear Source-Grid
Squares with Radial Wind Directions 2-9
Chi.l Chicago Grid Network 3-7
Chi.2 Maximum CO Concentration Locations for Each
Transportation Condition Given in Table Chi.l 3-8
Chi.3 Maximum HC Concentration Locations for Each
Transportation Condition Given in Table Chi.l 3-12
Chi.4 Maximum NOx Concentration Locations for Each
Transportation Condition Given in Table Chi.l 3-15
N.Y.I New York Grid Network . 3-23
N.Y.2 Maximum Concentration Location for All Pollutants
for All Conditions Listed in Tables N.Y.I and N.Y.2 . . . 3-26
Den.l Denver Grid Network 3-35
Den.2 Maximum Concentration Location for All Pollutants for
All Transportation Conditions Listed in Table Den.l
and Den.2 3-36
S.F.I San Francisco Grid Network 3-48
S.F.2 Maximum Concentration Location for All Pollutants for
All Transportation Conditions Given in Table S.F.I and
S.F.2 3-50
L.A.I Los Angeles Grid Network 3-60
L.A.2 Maximum CO Concentration Location 1 for 1967 and
Location 2 for 1977, Strategy 1, Strategy 2, and
Strategy 3 • 3-63
L.A.3 Maximum HC Concentration Location for All Transportation
Control Conditions Listed in Table L.A.I 3-67
L.A.4 Maximum NOx Concentration Location for All Transportation
Control Conditions Listed in Table L.A.I 3-69
D.C.I D. C. Grid Network 4-5
D.C.2 Maximum CO Concentration Locations for All Transportation
Conditions Given in Table D.C.i 4-9
vi i
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List of Figures (Continued):
Figure
Number Description Page
D.C.3 Maximum HC Concentration Location 1 for 1968
Uncontrolled Location 2 for All Other Transportation
Conditions Given in Table D.C.I 4-13
D.C.4 Maximum NOx Concentration Locations for All
Transportation Conditions Given in Table D.C.I .... 4-15
vi ii
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1.0 INTRODUCTION
The objectives of the Six Cities Transportation Analysis Project are
to evaluate transportation controls in the reduction of motor vehicle
emissions and to predict the impact of the expected emission reductions
on air quality in six metropolitan areas.
In the companion report entitled "Evaluating Transportation Controls
to Reduce Motor Vehicle Emission in Major Metropolitan Areas,"* TRW and
Institute of Public Administration/Technicron analyzed the various alter-
native transportation control strategies. Transportation controls were
defined broadly, but greatest attention was given to those controls capable
of being implemented by 1977. This analysis led to a general appreciation
of the applicability of the various alternatives. The evaluation was based
on a survey of existing published and unpublished data and upon discussions
with knowledgeable authorities in the areas of transportation control and
air pollution. This evaluation provided a general analytic framework upon
which the more specific analysis of the six metropolitan areas was prepared.
The following report details the data collection and specific analysis
performed in each of the six cities. The sources of transportation and other
data are identified and the limitations of the data base are described.
Analytic projections of emission rates and predicted concentration levels
are given for each of the defined transportation control conditions.
Section 2.0 describes the general analytic methodology used in the
analysis of the transportation data. Section 3.0 describes the analyses
specific to each metropolitan area. Section 4.0 presents a somewhat more
detailed discussion for Washington, D. C., which was used as a test case
for development of analytic procedures.
*(also called the IPA/TRW Report)
1-1
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2.0 GENERAL METHODOLOGY
2.1 SUMMARY
Transportation data in the form of vehicle miles traveled (VHT) by
geographic areas have been used as the basis for calculating emission rates
and air quality. The methodology involved:
Step 1 - Assignment of VMT and speed to elements of a grid network.
This required superimposing a rectangular yria network
consisting of one mile squares or one kilometer squares
over a base map of the metropolitan area and summation
of VMT from each of the individual roadways which may
fall within one of the small grids to ootain the total
VMT for each element or small grid in the grid network.
The speed for each grid of the grid network is obtained
by averaging the speeds from each element or roadway
within the grid for each time period required, using
the VMT along each element of roadway as a proportioning
factor. In this manner the many vehicular sources
moving within an individual grid can be represented
by a single stationary source, which produces the
same amount of emissions, equal to the size of tne
individual grid. This equivalent source is called an
area source because the emissions from tne grid or area
source are now considered as evenly distributed or
evenly produced over the entire area of the individual
grid.
Step 2 - Use of vehicle emission factors to calculate emissions
on a per-grid basis.
Step 3 - Conversion of emission rates to pollutant concentration
on a per-grid basis by the method af Gifford and HannavU.
Step 4 - Application of transportation control strategies to the
data base to obtain predicted concentration patterns for
each control strategy for the year 1977.
s. R. Hanna and F. A. Gifford, Jr., "Urban Air Pollution Modelling,"
Presented at 1970 International Air Pollution Conference of the
International Union of Air Pollution Prevention Associations,
ATDL Contribution No. 37.
2-1
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The resulting concentrations are presented graphically as isopleths
over a map of the metropolitan area. Pollutants considered were carbon
monoxide, hydrocarbons, and oxides of nitrogen, with carbon monoxide being
of primary interest.
2.2 TRANSPORTATION METHODOLOGY^
2.2.1 General Guidelines
In undertaking the phase of work involving evaluation and testing of
potential transportation control candidates, certain areas of general
agreement were reached with the Environmental Protection Agency. These
ground rules were required because of the short time available to complete
the work. Specifically, the following guidelines were used in developing
the methodology of the project analysis:
1. Attention was to be given to automobile air pollution problems
arising from travel into, out of, and within the central business
district (CBD) during the peak rush hours during a typical work
day.
2. In addition to the focus on the CBJ, the data would be confined
to that available from existing transport demand models used
in each of the six cities.
3. The strategies that were tested were selections from the
findings of the TRW/IPA Report (3) an(j would include only
three specific strategies: inspection and maintenance,
traffic flow controls, and motor vehicle/public transport
improvements (combined strategies). These strategies were
judged to be the most implementable and to produce reasonable
degrees of emission reduction.
A large number of cooperating agencies provided data for the analysis;
without their cooperation this phase of the project would have been
impossible. However, they are in no way responsible for the adjustments,
alterations, or manipulations undertaken of the data for the purpose of
the analysis. Any adjustments of interpretations of their data are
the responsibility of the project.
Institute of Public Administration and Teknekron, Inc., in cooperation
with TRW Inc., Evaluating Transportation Controls to Reduce Motor Vehicle
Emissions in Major Metropolitan Areas,Washington. D. C.~, November 20, 1972,
2-2
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2.2.2 Specific Approach
From urban transportation demand models (the traffic assignment
portions), VMT and speed data were obtained. Wherever possible, VMT and
speed data were obtained by zone. If no zonal information was available,
(4)
zonal estimates were madev . However, the emission levels are actually
used as average zonal values and are rough approximations rather than
point measures. In addition, the factors used to convert VMT and speed
data into emission levels themselves introduced errors which are of at least
equal magnitude to those introduced by allocation of link VMT into zones.
Because the requirements of the project were to develop eight-hour
and one-hour maximum levels of emission, VMT data had to be converted to these
units of time. Most of the VMT and speed information supplied (in the form
of computer printouts) was for a 24-hour average weekday (in some cases peak-
hour data were available) and, therefore, had to be adjusted to estimate the
eight-hour and one-hour maximum. These estimates were made utilizing daily
hourly traffic counts made available by the traffic departments and trans-
portation planning agencies in each of the cities.
Most of the traffic assignment data provided had base years in 1968
and 1969. These same models generally provided projected values for VMT
(and very often speeds) for the year 1980 and beyond. Interpolations,
therefore, had to be made for the year 1977. In making these interpolations
employment, residential, and population data were used wherever available.
Where these data or growth models were not available, interpolations were
generally based on straight line assumptions.
There is obviously a problem in allocating VMT along those segments of
the network which serve as boundaries to zones. The allocation of specific
link VMT to the zones on each side of the link boundary reduces the
reliability of the analysis used in describing the emission reduction
characteristics of each of the proposed strategies.
2-3
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Most of the traffic assignment models developed their projections
using a number of alternative assumptions with regard to the characteristics
of future highway networks and the mix between highway and transit, ror
the purposes of the analysis of this project, only the most conservative
highway construction assumptions were used. The traffic assignment data used
for each of the cities was for the highway alternative which assumed the
smallest amount of highway construction -- in the jargon of urban transporta-
tion planners -- for "committed systems."
In a number of cities speed information had to be estimated for
each of the zones. Where this was done, the speeds were based upon link-node
data using weighted averages weighting the respective speeds using link
volumes as weights.
2.3 MOBILE SOURCE POLLUTANT CONCENTRATION PROGRAM (MSPC)
The MSPC program handles the computations included in Steps 2,3, and
4 (Section 2.1). This program allows the use of the more complex form of
the Gifford-Hanna model described below.
The MSPC utilizes local traffic data and meteorological data to predict
pollutant concentration patterns for three mobile source pollutants. The
program input and output are oriented to a rectangular grid network wnich
overlays the city of interest. The results are presented in tabular form
as the average concentrations for each element of the grid network. Punched
card output was used to produce concentration isopleths or concentration
density maps which were overlaid on a map of the metropolitan area to give
a visual representation of the spatial distribution of the pollutant of
interest.
The program was also used to evaluate the effect of mobile source
pollutant control strategies such as direct or indirect vehicle emission
controls or traffic controls.
2-4
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2.3.1 Program Input
Three groups of input data are required (traffic data, meteorological
data, and emission factors for each pollutant.
a Traffic Flow Data
The resulting grid network of VMT and speed from Step 1 above
provide the basic traffic flow data required for emission calculations.
To correspond with the time periods specified by the National
Ambient Air Quality Standards, peak one-hour and peak eight-hour VMT are
required. For comparison with the ambient air quality standards for hydro-
carbons and nitrogen dioxide, a Larsen transformation was used to convert
estimates to three-hour and annual averages, respectively. Where these
data are not available, they were estimated as percentages of the 24-hour
VMT by using traffic count information at various stations within the area.
The program applied this percentage where necessary to obtain the appropriate
data format. Particular streets may vary significantly from the mean values
obtained by this procedure; however, the allocation of VMT to grids as
described above tends to minimize the effect of individual streets on the
predicted concentrations values for the individual grid.
Traffic speed data on a per-grid basis are required as an adjustment
to the average vehicle emission factors. Carbon monoxide and hydrocarbon
emissions decrease with increasing average vehicle speed; therefore, the
emission factors must be adjusted to be more realistic. EPA has published
emission factors curves*5' as a function of average vehicle speed for
carbon monoxide and hydrocarbons. These curves are incorporated in the
program.
"Compilation of Air Pollutant Emission Factors (Revised)"Environmental
Protection Agency, Office of Air Programs, February 1972, Office of
Air Programs Publication No. AP^42.
2-5
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The modal split of VMT must be considered, i.e., what is the
proportion of cars, buses, and trucks comprising the total VMT. data on
the modal split are not typically available on a detailed basis; therefore,
this factor is most readily accounted for in the formulation of area emission
factors as discussed below.
0 Meteorological Data
According to the Gifford-Hanna diffusion model used by the program,
concentrations have a strong inverse relation to wind speed. This implies
that concentrations will be greatest during periods of stagnation or very
low wind speed. This inverse relation (see Gifford-Hanna equation, page 2-8)
makes it clear that zero wind is not an allowable condition. The lowest
practical value of wind speed utilized has been 2.5 meters/second (basea
on discussion with meteorologists).
Wind direction is also a necessary input to the program because the
model accounts for contribution by upwind grids to the total concentration at
an individual grid. Several cases of wind speeds and directions were input to the
program for each metropolitan area. These cases were represented by
actual seasonal data (wind roses) or conditions considered typical of
high pollutant concentrations for the area. A frequency distribution
analysis of wind data for peak-hour and maximum eight-hour time periods
would be required to obtain a truly representative wind distribution
pattern for each city. Although hourly wind data are available for each
of the metropolitan areas considered, time did not permit this detailed
analysis of the wind data. The annual average wind speed and direction
and other "typical" wind speeds and directions were normally used for
each city. It should be noted that because the traffic data (24-nour
VMT, eight-hour VMT, peak-hour VMT) have no seasonal component, the
2-6
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spatial distribution of concentrations (the isopleth patterns) are a result
of the applied wind direction only and the numerical concentration values
may not truly be compared to the seasonal ambient data because they are
dependent only on wind speed and direction.
• Emission Factors
EPA has developed a computer program to produce emission factors
for the entire vehicle population for a given metropolitan area for any
calendar year from 1960 to 1990 for which vehicle age-type distribution
data are available. Emission factors are subject to revision as required
by changes in vehicles, control devices, "representative" driving cycles,
and measurement techniques.
• The Gifford-Hanna Diffusion Model
Many modeling approaches of varying degrees of complexity have
been developed. Consideration of available models led to selection of
the Gifford-Hanna model on the basis of ease of use and reasonable agree-
ment with more complex models^ '.
The Gifford-Hanna model assumes that the emissions from an area
the size of a city can be represented by a gridwork of area sources with
each source or grid having an emission strength Q (amount/m2-sec). (j is
assumed constant with time and "relatively smooth" in distance (i.e., g
does not vary by more than a factor of 10 from grid to grid). The crosswind
component of diffusion is then neglected in comparison with the vertical
component which is assumed to be Gaussian. The result is:
S. R. Hanna, "Simple Methods of Calculating Dispersion From Urban area
Sources," Contribution No. 46 from the Atmospheric Turbulence and
Diffusion Laboratory.
2-7
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o
where x = concentration (mg/m )
u = wind speed (m/sec)
AX = grid side length (m x 10 )
2
Q = central grid source strength (g/m -sec)
N = 10
a and b = empirical constants of urban stability averaging
0.15 (meters " ' and 0.75, respectively.
Figure 2-1 shows the Gifford-Hanna method for combining source grids
for various wind directions. This method accounts for the contribution of
upwind sources to the concentration at a given grid. The Gifford-Hanna
model is a form of Gaussian plume rather than a numerical integration model.
It does not adequately describe the accumulation of pollutants that may
occur due to prolonged stagnation conditions or due to the back-and-forth
or "sloshing" action apparent in Los Angeles or Denver basins. Therefore,
the maximum emissions and resultant "worst case" concentrations predicted
by application of the model are constrained by the maximum allowable wind
speed definition and the maximum emissions input (given by the maximum
eight hours and maximum one hour of traffic volume from annual average
weekday traffic counts) and may not agree with the "absolute" maximum
ambient concentration. Within these constraints the model appears to
be a very good predictor of carbon monoxide concentrations (as shown
by the comparison with Washington, D.C. ambient data. (See Section 4.3.)
• Stationary Sources
Available stationary source emissions data were included in order to
make predicted concentration values more realistic. In the six cities studied,
mobile sources contributed from 90 - 99 percent of the carbon monoxide
emissions and the impact of the stationary sources on concentrations values
was significant only in the vicinity of major point sources.
2-8
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AX
Upwind
Source
Grids
NNW
QNN
NW
E,NE
x^
•OE
c
WSW
/
\
ESE
sw
ssw
O
s
,
SSE
,
SE
Figure 2-1.
Scheme for Combining Rectilinear Source-und
Squares with Radial Wind Directions (See
Gifford-Hanna equation, page 2-8).
2-9
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Stationary sources represent a major portion of the hydrocarbon and
NOV emissions in the cities studied. It can be seen from the model equation
/\
above that the relative impact of large point source emissions on predicted
concentration values would be grossly overestimated by the area source
model because of the lack of stack height and plume rise considerations.
Several procedures were attempted to include these emissions as area sources;
however, results are poor. It is recommended that the large point sources
be modelled independently using AQDM or a similar Gaussian model and the
resultant concentrations could be added to the area source concentrations
to obtain a more realistic concentration estimate.
2.3.2 Program Output
A discussion of some program runs will give.a representative
sample of output
Three transportation conditions (and therefore three complete runs)
are considered as follows:
Run No. 1 (Current Conditions - 1968)
Case 1 Average summer wind
Case 2 Average winter wind
Case 3 "Nominal" (west wind at 6 m/sec)
Case 4 "Worst Case" (2.5 m/sec)
Pollutants CO, HC, NOY
J\
Run No. 2(Projected Conditions - 1977)
Assuming no additional transportation controls
Case 1 Average summer wind
Case 2 Average winter wind
Case 3 "Nominal" (west wind at 6 m/sec)
Case 4 "Worst Case" (2.5 m/sec)
Pollutants CO, HC, NOV
2-10
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Run No. 3 (Projected Conditions - 1977)
Assuming 25 percent reduction in CO emissions only
from a general inspection and maintenance program
Case 1 Average summer wind
Case 2 Average winter wind
Case 3 "Nominal" (west wind at 6 m/sec)
Case 4 "Worst Case" (2.5 m/sec)
Pollutant CO only
A sample output for a test run follows (Table 2-1 ) showing
Annual Emissions (tons/year) for each grid for HC and rtOx and
total emissions for a grid network.
Emission rates (mg/m2/sec) for each grid for both
mobile and total eight-hour and one-hour emissions for
CO are given as a sample. Actual listings include HC
and NOX emissions.
Pollutant concentrations (mg/m3) for CO for each of the
time periods (in 2. above) for each grid for "worst case"
conditions. Actual listings include all cases described
above.
2-11
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RUN: TEST
ANNUAL EMISSION RATFS (TflNS/YR)
3 RIO
1
2
3
4
5
6
,7
;a
'9
10
11
12
13
14
15
16
17
19
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
X(KM) Y(K^)
307.50 4294.50
308.50 4294. 50
309.50 4294.50
310.50 4294.50
311.50 4294.50
312.50 4204.50
313.50 4294.50
314.50 4294.50
307.50 4295.50
303.50 4295.50
309.50 4295.50
310.50 4295.50
311 .50 4295.50
312.50 4295.50
313.50 4295.50
314.50 4295.50
307.50 4296.50
303.50 4296.50
309.50 4296.50
310.50 4296.50
311.50 4296.50
312.50 4296.50
313.50 4296.50
314.50 4296.50
307.50 4297.50
308.50 4297.50
309.50 4297.50
310.50 4297.50
311.50 4297.50
312.50 4297.50
313.50 4297.50
314.50 4297.50
307.50 4298.50
303.50 4298.50
309.50 4298.50
310.50 429«.50
311.50 4298.50
312.50 4298.50
313.50 4298.50
314. SO 4298.50
307.50 4299.50
308.50 4299.50
309.50 4299.50
310.50 4219.50
311.50 4209.50
H2.*0 4299.50
313.50 42^9.50
314.50 4299.50
307.50 4300.50
303.50 4300.50
UJ
TTT EMM
215.
215.
215.
215.
1304.
1304.
1304.
1304.
413.
413.
413.
413.
816.
816.
816.
816.
284.
284.
189.
189.
277.
277.
277.
277.
211.
211.
211.
211.
221.
221.
221.
221.
215.
215.
215.
215.
1304.
1304.
1304.
1304.
413.
413.
413.
413.
816.
816.
816.
816.
284.
284.
MOB EMM
215.
215.
215.
215.
1304.
1304.
1304.
1304.
413.
413.
413.
413.
816.
816.
816.
816.
234.
284.
189.
189.
277.
277.
277.
277.
211.
211.
211.
211.
221.
221.
221.
221.
215.
215.
215.
215.
1304.
1304.
1304.
1304.
413.
413.
413.
413.
816.
816.
816.
816.
284.
284.
n^
TOT EMM
37.
37.
37.
37.
224.
224.
224.
224.
71.
71.
71.
71.
140.
140.
140.
140.
49.
49.
33.
33.
48.
48.
48.
48.
36.
36.
36.
36.
38.
38.
38.
38.
37.
37.
37.
37.
224.
224.
224.
224.
71.
71.
71.
71.
140.
140.
140.
140.
49.
49.
MHR EMM
37.
37.
37.
37.
224.
224.
224.
224.
71.
71.
71.
71.
140.
140.
140.
140.
49.
49.
33.
33.
48.
48.
48.
48.
36.
36.
36.
36.
38.
38.
38.
38.
37.
37.
37.
37.
224.
224.
224.
224.
71.
71.
71.
71.
140.
140.
140.
140.
49.
49.
NU
TOT EMM
17.
17-
17.
17.
103.
103.
103.
103.
33.
33.
33.
33.
65.
65.
65.
65.
23.
23.
15.
15.
22.
22.
22.
22.
17.
17.
17.
17.
18.
18.
18.
18.
17.
17.
17.
17.
103.
103.
103.
103.
33.
33.
33.
33.
65.
65.
65.
65.
23.
23.
'40(3 EMM
17
17
17
17
103
103
103
103
33
33
33
33
65
65
65
65
23
23
15
15
22
22
22
2?
17
17
17
17
18
1«
13
IB
17
17
17
17
101
103
103
103
33
33
33
33
6*
6^
6^
65
23
23
Table 2-1. Sample Output for Mobile Source Pollutant Concentration Program
2-12
-------
RUN: TRST CASC
ANNUAL EMISS1UN K/v I hb UUMi/YR)
GRID
51
52
53
54
55
56
57
58
59
60
61
62
63
64
•mr AI
X(KM)
309.50
310.50
311.50
312.50
313.50
314.50
307.50
309.50
309. 50
310.50
311.50
312.50
313.50
314.50
Y(KH
4100.
4300.
4300.
4300.
4300.
4300.
4301.
4301.
4301.
4301.
4301.
4301.
4301.
4301.
,
50
50
50
50
50
50
50
50
50
50
50
50
50
50
^. ,.
TOT EMM
I 99.
1P9.
277.
277.
277.
277.
211.
211.
211.
211.
221.
221.
221.
221.
MOB EMM
199.
1«9.
277.
277.
277.
277.
211.
211.
211.
211.
221.
221.
221.
221.
^Qt;^-
1
TOT EMM
33
33
48
48
48
48
36
36
36
36
38
38
38
38
thrift A.
n^
•
•
•
*
*
•
•
•
*
•
•
•
•
*
MOB EMM
33.
33.
48.
48.
48.
48.
36.
36.
36.
36.
38.
33.
38.
38.
TOT EMM
15
15
22
22
22
22
17
17
17
17
18
18
18
18
?•»£•*
NU
•
.
.
.
•
.
.
.
.
.
.
.
•
.
X
MOB FMM
15.
15.
22.
22.
22.
22.
17.
17.
17.
17.
IB.
18.
18.
18.
7*4.^.
Table 2-1. (Continued)
2-13
-------
RUN: TEST CASE
EMISSION RATES (MG/SEC/SQ METER)
POLLUTANT: CO
GRID
8HR TOT
8HR MOB
IHR TOT
1HR MOB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
0.0089
0.0089
0.0089
0.0089
0.0541
0.0541
0.0541
0.0541
0.0171
0.0171
0.0171
0.0171
0.0338
0.0338
0.0338
0.0338
0.0118
0.0118
0.0079
0.0079
0.0115
0.0115
0.0115
0.0115
0.0088
0.0088
0.0088
0.0088
0.0092
0.0092
0.0092
0.0092
0.00 9
O.OD89
0.0089
0.0089
0.0541
0.0541
0.0541
0.0541
0.0171
0.0171
0.0171
0.0171
0.0338
0.0338
0.0338
0.0338
0.0118
0.0118
0.0089
0.0089
0.0089
0.0089
0.0541
0.0541
0.0541
0.0541
0.0171
0.0171
0.0171
0.0171
0.0338
0.0338
0.0338
0.0338
0.0118
0.0118
0.0079
0.0079
0.0115
0.0115
0.0115
0.0115
0.0088
0.0088
0.0088
0.0088
0.0092
0.0092
0.0092
0.0092
0.0089
0.0089
0.0089
0.0089
0.0541
0.0541
0.0541
0.0541
0.0171
0.0171
0.0171
0.0171
0.0338
0.0338
0.0338
0.0138
0.0118
0.0118
0.0192
0.0192
0.0192
0.0192
0.1162
0.1162
0.1162
0.1162
0.0363
0.0363
0.0363
0.0363
0.0754
0.0754
0.0754
0.0754
0.0230
0.0230
0.0155
0.0155
0.0231
0.0231
0.0231
0.0231
0.0188
0.0188
0.0188
0.0188
0.0190
0.0190
0.0190
0.0190
0.0192
0.0192
0.0192
0.0192
0.1162
0.1162
0.1162
0.1162
0.0363
0.0363
0.0363
0.0363
0.0754
0.0754
0.0754
0.0754
0.0230
0.0230
0.0192
0.0192
0.0192
0.0192
0.1162
0.1162
0.1162
0.1162
0.0363
0.0363
0.0363
0.0363
0.0754
0.0754
0.0754
0.0754
0.0230
0.0230
0.0155
0.0155
0.0231
0.0231
0.0231
0.0231
0.0188
0.0188
0.0188
0.0188
0.0190
0.0190
0.0190
0.0190
0.0192
0.0192
0.0192
0.0192
0.1162
0.1162
0.1162
0.1162
0.0363
0.0363
0.0363
0.0363
0.0754
0.0754
0.0754
0.0754
0.0230
0.0230
Table 2-1. (Continued)
2-14
-------
RUN: TEST CASE
EMISSION RATES
POLLUTANT: co
(MG/SEC/SQ METER)
GRID
8HR TOT
8HR MOB
IHR TOT
Table 2-1. (Continued)
IHR MOB
51
52
53
54
55
56
57
58
59
60
61
62
69
64
0.0079
0.0079
0.0115
0.0115
0.0115
0.0115
0.0088
3.0088
0.0088
0.0088
0.0092
0.0092
0.0092
0.0092
0.0079
0.0079
0.0115
0.0115
0.0115
0.0115
0.0088
0.0088
0.0088
0.0088
0.0092
0.0092
0.0092
0.0092
0.0155
0.0155
0.0231
0.0231
0.0231
0.0231
0.0188
0.0188
0.0188
0.0188
0.0190
0.0190
0.0190
0.0190
0.0155
0.0155
0.0231
0.0231
0.0231
0.0231
0.0188
0.0188
0.0188
0.0188
0.0190
0.0190
0.0190
0.0190
2-15
-------
RUN: TEST CASE
POLLUTANT CONCENTRATION (MG/CU8IC METER)
POLLUTANT: CO CASE: WORST
GRID
8HR TOT
8HR MOB
iHR TOT
1HR MOB
I
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
0.7669
0.7669
0.7669
0.7669
2.5847
4.6570
4.6570
4.6570
1.4752
1.4752
1.2025
1.2025
1.8755
2.0882
2.4136
3.5861
1.0143
1.0143
1.0341
0.9343
0.9609
1.0073
1.1278
1.2159
0.7555
0.7555
0.8551
0.8551
0.9541
0.9386
0.8590
0.8782
0.7669
0.7669
0.7625
0.7625
2.6425
3.2169
3.2722
3.2604
1.4752
1.4752
1.2025
1.2025
1.8728
2.0854
2.4495
2.6877
1.0143
1.0143
0.7669
0.7669
0.7669
0.7669
2.5847
4.6570
4.6570
4.6570
1.4752
1.4752
1.2025
1.2025
1.8755
2.0832
2.4136
3.5361
1.0143
1.0143
1.0341
0.9843
0.9609
1.0073
1.1278
1.2159
0.7555
0.7555
0.8551
0.8551
0.9541
0.9386
0.8590
0.8782
0.7669
0.7669
0.7625
0.7625
2.6425
3.2169
3.2722
3.2604
1.4752
1.4752
1.2025
1.2025
1.8728
2.0854
2.4495
2.6877
1.0143
1.0143
1.6509
1.6509
1.6509
1.6509
5.5567
10.0093
10.0093
10.0093
3.1269
3.1269
2.5586
2.5586
4.1335
4.6312
5.3303
7.8496
1.9806
1.9806
2.1211
2.0260
1.9786
2.0756
2.3576
2.5639
1.6155
1.6155
1.7561
1.7561
1.9958
1.9490
1.7833
1.8235
1.6509
1.6509
1.6372
1.6372
5.6307
6.8650
7.0063
6.9806
3.1269
3.1269
2.5586
2.5586
4.1250
4.6227
5.3764
5.8881
1.9806
1.9806
1.6509
1.6509
1.6509
1.6509
5.5567
10.0093
10.0093
10.0093
3. 1269
3.1269
2.5586
2.5586
4.1335
4.6312
5. 3303
7.8496
1.9806
1.9806
2.1211
2.0260
1.9786
2.0756
2.3576
2.5639
1.6155
1.6155
1.7561
1.7561
1.9858
1.9490
1.7833
1.8235
1.6509
1.6509
1.6372
1.6372
5.6307
6.8650
7.0063
6.9806
3.1269
3.1269
2.5586
2.5586
4.1250
4.6227
5.3764
5.8881
1.9806
1.9806
Table 2-1. (Continued)
2-16
-------
RUM: TEST CASE
POLLUTANT CONCENTRATION (MG/CUBIC
POLLUTANT: CO CASE: WORST
METER)
GRID
8HR TOT
8HR MOB
1HR TOT
Table 2-1. (Continued)
1HR MOB
51
52
53
54
55
56
57
58
59
60
61
62
63
64
1.0341
0.9343
0.9609
1.0073
1.1261
1.2142
0.7555
0.7555
0.8551
0.8551
0.9541
0.9386
0.8590
0.8782
1.0341
0.9843
0.9609
1.0073
1.1261
1.2142
0.7555
0.7555
0.8551
0.8551
0.9541
0.9386
0.8590
0.8782
2.1211
2.0260
1.9786
2.0756
2.3523
2.5586
1.6155
1.6155
1.7561
1.7561
1.9858
1.9490
1.7833
1.8235
2.1211
2.0260
1.9786
2.0756
2.3523
2.5586
1.6155
1.6155
1.7561
1.7561
1.9858
1.9490
1.7833
1.8235
2-17
-------
A punched card output was submitted to a plotting routine to obtain
isopleth maps for each of the pollutants and transportation conditions
described in Section 2.3.2.
2.4 STRATEGIES EVALUATION
2.4.1 Strategy 1 - Inspection and Maintenance
Broadly defined, the inspection and maintenance programs involve
(1) the inspection of in-use vehicles, (2) the identification of high
emitters (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 without inspection. For example, spark plugs or
breaker points could be replaced on the basis of their expected life.
Corrective action might also be required 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 actions need
to be taken and (2) to reduce possible underservicing or overservicing.
For these reasons, we assume that inspection should be an integral part
of any effective program involving maintenance.
On the basis of research performed by TRW Inc., Northrop Corporation,
and the State of New Jersey, as well as information from EPA officials,
in the Bureau of Mobile Source Pollution Control (see IPA/TRW Report for
details of these references), it appears that the most likely initial
reduction in aggregate carbon monoxide emissions from an inspection and
maintenance program would be on the order of 10 to 25 percent. However,
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).
2-18
-------
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" deterioration occurred after nine
months, an annual aggregate emission reduction of only 7.5 percent would
be achieved. Actual emission reductions, achievable from inspection and
maintenance may also be overstated due to difficulties in (1) obtaining
complete compliance from all in-use vehicles owners and (2) securing
governmental cooperation in multi-jurisdictional metropolitan areas.
Based on these findings, the strategy was applied as a reduction
in CO emissions using values of 5 and 25 percent for illustrative purposes
and a value of 10 percent as the most likely reduction. A reduction in
hydrocarbon emissions of 12 percent was assumed most likely based on the
November 1972 EPA document "Control Strategies for In-Use Vehicles."
2.4.2 Strategy 2: Traffic Flow Controls
Based on the findings in the IPA/TRW report, evaluation of specific
city data and the reconnaissance meetings with transportation and other
personnel in the cities, traffic flow control strategies were developed
for each of the six cities. The data available for each city did not
permit, generally, classification into fine-grained geographic areas
(e.g., the eight rings used for Washington, D.C.). In view of the fact
that.-the-.impact of flow controls was based on general experience and
judgment, for the purposes of project analysis, the respective cities
(except Washington, D.C.) were divided into three broad geographic
areas: (1) the CBD or core, (2) an area surrounding the core but still
within the political boundaries of the city, and (3) the remaining area
outside the boundaries of the city. This three-way division allowed
relatively easy division of zones while still permitting our analysis
to be somewhat more fine grained than would otherwise be possible.
2-19
-------
Using the above classification system, Table 2-2 indicates the speed
adjustment factors that were used in each of the six cities. It should be
noted that in each city we have assumed implementation of the proposed traffic
flow control strategy within a one-year period. This must be considered
optimistic in the face of repeated statements by traffic engineers and city
administrators that it would take a minimum of two to four years to implement
traffic flow control plans — including computerization, ramp metering,
surveillance, and other controls. However, assuming a concerted effort
and commitment on the part of each city and the funding available (in time)
from the Federal government, a one-year period for implementation might
be possible, especially since each of the six cities already has some
plans for improved traffic flows, considerable experience, and some staff
already available. However, even with these advantages, it is patently
clear that the assumption of one year for implementation is still optimistic.
In connection with developing the factors shown in Table 2-2, major
emphasis was placed on speed values during the peak hour. However, because
eight-hour maximum VMT periods were required for the analysis, the question
was raised as to whether to use the same speed change assumptions as for
the maximum one-hour period. In this connection, the following assumptions
were used based on conversations with traffic engineers in each metropolitan
area.
1. It would be expected that speed changes due to improved
flow controls would result in substantially lower improvement
levels during the off-peak period. The reasons are:
a. During the off-peak period, the available capacity
is not being used and speeds are generally higher
than during the peak periods and hence less margin
for improvements (or need).
b. Most improvements in traffic control are aimed at tne
peak hour and in many cases only marginally spin-off
benefits to the off-peak hours. For example, special
one-way streets that convert to two ways during the
off-peak, special peak-hour light progressions, etc.
Thus, the improvements do not help very much during
the off-peak periods.
2-20
-------
Table 2-2. Speed Adjustment Factors
CITY
Area to Which Speed Factor
Be Applied
Core (CBD) Remainder of
City
Below Is To Time Sequence
to be Used in
Area Outside Applying
City Boundary Strategy
Chicago
Dist. of Columbia
Denver
Los Angeles
New York City
San Francisco
10%
10%
5%
10%
5%
10%
12%
15%
a/
5%
12%
5%
12%
5%
15%
5%
15%
As in B.C.
Year 1- 0
Year 2-Full Eff.
Year 3 0
As in D.C.
As in D.C.
As in D.C.
Year 1-0
Year 2-Full Eff.
Year 3*1/2 Eff.
Year 4-0
&_l The following factors were used for, Washington, D.C. where data permitted
analysis by rings:
Speed Ring —
As Defined by
Grid Numbers
(mph)
10
15
24.2
28.5
30
45
Change in Speed from Base Year (%)
1 2 3 4 to 1977
Corresponding
Ring Number
0
0
0
0
0
0
10
12
15
15
15
20
-10
-12
l
-15
-15
-15
-20
0
0
0
0
0
0
0
1
2
3
4
5-6-7-8
2-21
-------
c. The volume of vehicles during the off-peak is
usually lower and the average speed higher so
improvement percentages are likely to be sub-
stantially lower, if anything at all (perhaps
with the exception of situations where streets
are saturated all the time). ,
Within this framework, it was therefore considered very unlikely that
the percentage changes used for speed improvements for the peak hour would
obtain during the off-peak period. In terms of the analysis, the speed
change assumptions used for the maximum one-hour were not considered
likely to be the same (percentages) as for the eight-hour maximum. In
determining, therefore, what percentage speed change to use for the eight-
hour maximum, it was necessary to ascertain what percentage of our assumptions
of percent change in speed during the peak-hour would hold true for the
off-peak hour.
Generally in the six cities in the study, the eight-hour maximum
VMT period fully encompassed one of the peak-hour periods and part of
another. It was, therefore, quite clear that we could not assume that
no speed changes would result from traffic flow improvement for the eight-
hour maximum period when in fact the average speed change due to traffic
flow controls during the eight-hour maximum would be influenced by the
presence of the two (or part of both) peak hours. For example, in
Washington, D.C., the maximum eight-hour peak period fell somewhere
between the hours of 11 a.m. - 7 p.m. or 12 p.m. - 8 p.m. and included
about 50 percent of the 24-hour VMT. Conversations with the traffic
engineers indicated that an optimistic assumption is that about 50 percent
of the speed improvements would apply for the eight-hour period, and this
assumption was used. It is, however, relatively optimistic.
2-22
-------
2.4.3 Strategy 3: Motor Vehicle Restraints
In order to provide for a reasonable motor vehicle restraint strategy,
a review of the available data on motor vehicle restraints was undertaken
to determine the extent to which evidence was available that would provide
some indication of the range of expectations for reductions in VMT. This
data review was combined with an evaluation of the specific implementation
plans of the six cities, particularly with reference to their own programs
for motor vehicle restraints. These implementation plans were also
related to the city reconnaissance reports. This section considers each
of the latter three elements and presents the assumptions used with respect
to the application of a motor vehicle restraint strategy.
• Review of Available Data
A review of data was undertaken as part of the preparation of
the IPA/TRW Report. As was noted in that report, there is very little
evidence available as to what might be expected in the way of reduction
of VMT through the application of motor vehicle restraints. On the
basis of the best available data and judgment, and assuming parking con-
trols or some other form of road pricing, the range of reductions in VMT
appears to be between 5 and 20 percent. However, 20 percent appears to
be the upper limit of any practical action that might be taken within
the time frame of the study -- that is by 1977. In Washington, for example,
reductions in VMT of 20 percent would probably involve tripling and, perhaps,
quadrupling parking rates. The unlikelihood of that level of restraint
being implemented has been described in the above cited report.
In addition, VMT reductions of 15 to 20 percent may have to be
accompanied by major improvements in public transportation. The cost for
these improvements would be substantial and require major appropriations
at the Federal level.
' 'The Final Report, Evaluating Transportation Controls To Reduce Motor
Vehicle Emissions in Major Metropolitan Areas, estimates indicated about
$14 billion of investment would be required in the six cities for
completion of existing public transport plans plus some moderate improve-
ments such as people movers. This level of investment, however, would
probably still not be sufficient or include the scope of changes which
might be needed.
2-23
-------
Data available for the Bay Area Rapid Transit System (BART) in
San Francisco provide estimates of the reductions expected in motor vehicle
use for 1975. These estimates indicate that in the four counties of
Alameda, Contra Costa, San Francisco, and San Mateo the number of trips
i
diverted from motor vehicles to BART by 1975 would reduce the vehicle
miles of travel per day by 2.1 percent. In specific important line-haul
corridors where transit is more competitive, the diversion factors (for
example, Bay Bridge) were as high as 8.1 percent; but in general the
estimates ranged below 10 percent (on the average) . They also ranged
well below 10 percent if all corridors were taken into account.
Modal split models which predict the percentages of trucks and
buses in the vehicle population under varying conditions were examined
for Washington, Baltimore, and Minneapolis. These models substantiated
the fact that significant changes would be required in parking rates
before major diversions in motor vehicle use would occur. In Washington
doubling and tripling was implied as it was in Baltimore and Minneapolis.
To achieve reductions in motor vehicle use in the range of 20 to 25 per-
cent, implied comprehensive parking control programs with parking space
taxes of $60 to $80 a month for all spaces — private and otherwise --
and elimination of all on-street parking. Only under these severe conditions
could one hope to achieve 20 to 25 percent VMT reductions.
From the available evidence and judgment, the conclusion was
reached that VMT reductions of over 20 percent are quite unrealistic, at
least in the six cities in the study;and by 1977 the reductions in VMT
from motor vehicle restraints are likely to be under 20 percent -- probably
well under 20 percent.
• Review of Implementation Plans
The limited use of motor vehicle restraints in any form is readily
apparent in the Implementation Plans of the six cities. It is only in
San Francisco and Los Angeles that any estimates are provided for reductions
through motor vehicle restraints. In both cities, a 20-percent reduction
is provided; however, these are values estimated by the state and there
2-24
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is no evidence provided that such reductions could be achieved. Furthermore,
there is no plan provided as to how such reductions could be achieved or
whether it is realistic. For example, the San Francisco plan notes that
through public transportation, car pooling, and changes in working schedules,
they hope to reduce emissions. They point out, however, "the level of
achievement of these measures cannot be closely estimated. The goal, which
is set on the optimistic side, is to reduce traffic by 20 percent.^ Nothing
is indicated as to how this 20 percent would be realized or the basis on
which it is estimated. In the Los Angeles plan, the same 20 percent is
used; and, in fact, the language used to describe the plan is exactly the
same as that used for San Francisco with no further evidence.
For the other cities reviewed, the possibilities were unspecified
with the exception of Washington, D.C., where a number of limited parking
facility proposals are provided (including a ban on on-street parking,
sharp increases in commercial parking lot fees, and other potential control
devices). In all the cities, there is considerable reluctance to indicate
any form of motor vehicle restraint or identify in any specificity its
content or the way in which these reductions would be achieved.
• Reconnaissance Trips
Reconnaissance of the six cities substantiated the difficulty
of implementing motor vehicle restraints. In fact, with perhaps only
minor exceptions, the trend appears to be toward considerable resistance
for any kind of motor vehicle restraint. This does not suggest that
restraints may not come into effect or that, in time, they may not be
accepted. However, within the framework of attempting to achieve
emission standards by 1977, there appears to be considerable opposition
to be overcome. For example, in San Francisco where a 25-percent parking
tax has been in effect on commercial space, we were informed that there
had been little or no impact on motor vehicle use with the possible
Francisco Implementation Plan, page 61,and Los Angeles Implementation
Plan, page 120.
2-25
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exception of some shift to on-street parking. There has been no change in
transit ridership, and there is considerable pressure to remove ana/or
substantially reduce the parking tax from 25 to 10 percent. There is indi-
cation that the proponents of a reduction might be successful.
Again, in San Francisco the use of car pool experiments suggests
that it is going to be very difficult to achieve even limited goals of
diversion (3000 vehicles per day to car pools) and there does not appear
to be any overwhelming movement toward supporting motor vehicle restraints
in San Francisco.
In New York City restraint on motor vehicle use has been an
important element in the city's policy for dealing with congestion,
particularly in view of the long history of congestion. A number of vehicle
ban proposals have been suggested; however, in general, they have been
politically unacceptable. For example, efforts to develop a Madison
Avenue Mall have been generally deterred and it appears likely that only
limited implementation of the Mall will occur.
In Los Angeles the need for regional controls in order to solve
the pollution problem (as described in the Interim Report) indicates that
reductions of 20 percent VMT would have to be undertaken throughout the
area since reductions in the CBD alone would not be particularly helpful.
The uniformity of the distribution of the emissions and the difficulty of
implementing them in the Los Angeles area(given the multiplicity of govern-
ments and the general importance of the automobile in the daily traffic
movements) suggests extraordinary difficulty in implementing any kind of
major restraint effort.
In Washington, D.C., it was proposed to provide an all-day parking
tax of $1 a day to be implemented as part of the effort to reduce VMT.
Estimates ranged from 8 to 16 percent reduction in trips; overall reductions
in the range of four percent. Major opposition resulted in postponement
of the issue to 1973; and again it appears very unlikely that even a
small tax of a dollar a day (which would not, perhaps, result in more
2-26
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than a 4 to 5 percent reduction) will be passed, if at all, before 1974
The Chicago Plan indicated that no motor vehicle restraints were
contemplated with emphasis being placed upon the automobile manufacturers
providing the necessary reduction through changes in engine design and/or
control devices and improvements in traffic flow control s. Reconnaissance
made it quite clear that there was opposition on the part of the city
government to any policy of motor vehicle restraint.
Finally, in Denver indications are that only small reductions
may be expected from any kind of motor vehicle restraint program. The
city is opposed to any kind of motor vehicle restraint; the administration
has no present plans for motor vehicle controls and does not intend to
implement any. We were advised that the automobile is an important and
basic element in the life of residents in the City of Denver and that no
one anticipates any major restraints.
• Summary
In view of the reconnaissance experience, the review implementation
plans and the findings of the IPA/TRW Report and other evidence reviewed,
the following conclusions appear relevant:
1. It would appear at the present time that it is not politically
feasible to achieve any major program of motor venicle restraint
in any of the six cities under review. Though minor programs
could emerge in the way of price increases for parking, no
significant impact is likely to have any major effect by 197b
and only slightly more for 1977.
2. The reductions of 5 t9 20 percent indicated in the Interim
Report, though within the realm of possibility, must be
considered to represent broad ranges. For the six cities
under review and based upon an evaluation of opinion in the
cities and the other elements described, 20 percent appears
to be in the very upper limits of what is even realistically
feasible and seems to be a very unlikely possibility for any
of the six cities.
2-27
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• Assumptions
Within the context of the difficulties described above, the following
assumptions were made with respect to the potential for reductions in VMT
through the use of a motor vehicle restraint strategy:
1. A motor vehicle restraint strategy will have to be accompanied
by very substantial improvements in transit involving fairly
substantial sums of investment.
2. The most feasible restraint appears to be some form of pricing
policy -- perhaps increases in parking costs, possibly toll
roads or some other forms of road pricing. This appears more
feasible because of the somewhat more subtle characteristics
of the impact so that public opposition to the motor vehicle
restraint (particularly from motor vehicle owners) might be
somewhat less. Major vehicle bans and frontal assaults of a
similar nature are likely to encounter fierce opposition.
3. Of all the range of possibilities, all assumptions about reductions
of VMT must be considered optimistic in the light of a target
of 1977. For purposes of testing a motor vehicle strategy,
the following ranges were used:
Range of Reductions in VMT From
Motor Vehicle Restraints
Six Cities Study
1. Moderately optimistic - 5 percent
2. Optimistic - 10 percent
3. Very optimistic - 15 percent
After careful consideration of all of the evidence and recognizing
that a considerable amount of judgment is involved, it was decided that none
of the six cities are likely to achieve even 15 percent reductions by 1977.
It was also assumed that motor vehicle restraints are likely to have some positive
impact on traffic flow controls through their reductions in the volume
of traffic by retarding or slowing down the extent to which traffic flow
improvements are used up by generated traffic.
2-28
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In the context of the previous discussion, Table 2-3 summarizes tne
Strategy 3 factors which were applied, including the effect that might be_
considered with respect to traffic flow controls. The traffic flow control
impact of a motor vehicle restraint strategy was based on estimated annual
traffic growth (largely) in the CBU areas of the respective six cities.
• Analytical Application of Strategy 3
Strategy 3 was applied to the 1977 data base as a combination
of traffic restraints, traffic flow control, and a reduction in CO and hydro-
carbons due to the inspection and maintenance program. This combined
strategy assumes for the purpose of analysis that the full impact of
each control element will be achieved during 1977. The application procedure
does not allow the impact of motor vehicle restraints on traffic flow to
be displayed on Table 2-3. Since the analysis is performed for a specific
year (1977), the retarding impact of motor vehicle restraints in holding
back generated traffic resulting from speed improvements are not taken
into account
2-29
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Table 2-3. Motor Vehicle Restraint Factors
City
Washington, D.C.
Chicago
New York City
Denver
San Francisco
Los Angeles
City
Denver
Washington, D.C.
New York City
Chicago
San Francisco
Los Angeles
A: OFFSET TO TRAFFIC GROWTH
Estimated Years to Offset Growth in Traffic
Growth Rate with VMT Reduction of
(in CBD) 5% 107. 157.
57. 123
2 357
3 234
5 123
2 357
4 134
B: STRATEGY III FACTORS
Motor Vehicle Impact Period: Year
Restraint in
VMT 0 1 2345
57
Year) ment Yr.)
in ii ii _1fY7 - k
in ii ii _ i n°/ _ _ K.
<; ii it _S7--- - K,
in ii it .107- - N
5 " " -57. £
Years Before Traffii
Flows Offset: Year
12345
Imp. ^
ii tw
v
ii ^
ii \
. ->
2-30
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3.0 SIX CITY TRANSPORTATION STUDY RESULTS
3.1 INTRODUCTION
The methodology developed for the evaluation of the impact of trans-
portation controls on air quality was applied to six major metropolitan
areas including: Chicago, New York, Denver, San Francisco, Los Angeles,
and Washington, D.C. Three transportation control conditions were con-
sidered for analysis as follows:
(1) current conditions - as close to existing conditions as trans-
portation data will allow,
(2) projected transportation conditions for 1977 assuming 1975
automotive emissions standards are met, and
(3) projected conditions for 1977 with estimates of the effects of
several transportation controls.
The particular controls evaluated were selected as described in
Section 2.4 of this report. Although many potential controls were con-
sidered, only three were selected for air quality impact calculations due
to project and data constraints. These were:
• Strategy 1 - Inspection and Maintenance
The strategy was applied as a 10 percent reduction in CO emissions
and a 12 percent reduction in Hydrocarbon emissions.
• Strategy 2 - Traffic Flow Controls
Average vehicle speeds were increased by the percentages given
in Table 2-1 to indicate th4 Impact of this strategy.
• Strategy 3 - Combined Strategies
The impact of Strategies 1 and 2 were combined with a VMT reduc-
tion due to vehicle restraints as shown in Table 2-2. (Vehicle
restraints and resultant VMT reductions used were those considered
most likely to occur by 1977.)
3-1
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3.2 METROPOLITAN AREA ANALYSIS - CHICAGO
3.2.1 Data Base and Methodology
3.2.1.1 Transportation Data
• Basic Data
Basic data were provided by the Chicago Area Transportation Study
(CATS) and consisted of VMT and speed data by zone for peak and off-peak
periods for 1968/69 and projections to 1985.
Specifically, the project was supplied with computer printouts
showing volume and speed for the 1900 districts comprising the Chicago
region. The project was also provided with material on traffic counts and
other data from the traffic departments of both the State of Illinois and
the City of Chicago. The characteristics of the two networks (base year
and projected) are as follows:
Highway Network
Assignment 901: is the 1968/1969 eight-county highway
network.
Assignment 903: is the 1968/1969 network with major
highway improvements presently under construction or
improvements to be initiated in the near future.
According to CATS, the trips used in the simulation and the trip lengths
used to calibrate CATS distribution model are from five different sources.
1. For the area inside CATS 1956 cordon line (approximately Cook
County), Assignment 901 uses information developed by a major
update of CATS 1956 survey done in 1965 and Assignment 903
uses estimates for 1980 developed from this update.
2. For the area outside the 1956 cordon line in Illinois, both
assignments use information from three smaller studies done
in the region. Assignment 901 uses data from surveys taken
during 1966-1969, and Assignment 903 uses 1985 estimates
made from these surveys.
3. For Indiana, both assignments use information provided by
Lake-Porter Counties Regional Transportation and Planning
Commission. Assignment 901 uses a 1968-1969 estimate and
Assignment 903 uses a 1985 estimate.
3-2
-------
• Interpolation Factors
In interpolating 1985 VMT projections to 1977, population,
employment and land-use data were used/ ' Factors were developed for
interpolating for each township and used to estimate zonal values for 1977.
The projected 1977 VMT is the 1968 VMT, plus the township factor multiplied
by the difference in 1985 VMT projections.
e.g.: 1977VMT,, - 1968 VMT... + Factor. (1985 VMT.. 1968 VMT..)
' J '3 i 1J 1J
where i = township
j = zone within township.
The annual percent projected increase in population from 1965 to
1975 and from 1975 to 1985 were obtained. These percentage figures were
used to determine the estimated ratio of growth from 1968 to 1977 compared
to the period 1968 to 1985.
• Estimates of Eight- and Peak-Hour VMT
In Chicago, peak-hour speed and VMT data were available directly
from the assignment model. However, estimates had to be made for the
eight-hour period of maximum VMT.
The calculation of this eight-hour peak was based on two sources:
a. The Bureau of Street Traffic, Traffic Volume Factors for
Preferential Street System of Chicago, (Revised, October
1968).Counts were taken at 40 locations distributed
throughout Chicago in late 1966, '67 and '68. Page 4 of
the study "Average Distributions of Traffic Volumes by
Hour on the City of Chicago Preferential Streets" indicated
the (two-way) percentages of cars by hour for the 40 streets.
A quick tabulation /indicated that the maximum was 47.4
percent between the hours of 12 noon and 8 p.m.
b. The Bureau of Street Traffic, Cordon Count: Central Business
District, 1971. Table II (p. 34), "Comparison by Fifteen
Minute Periods of Vehicles Entering and Leaving the CBD of
Chicago — Bounded by Roosevelt Road, Lake Michigan and the
River." Running eight-hour totals were obtained; these
* ' The township adjustment factors were determined through interpolation
of population projections provided in Northeastern Illinois Planning
Commission "Metropolitan Planning Paper No. 10: Population, Employment
and Land Use Forecasts for Counties and Townships in Northeastern Illinois"
Chicago: September 1968 (mimeo).
3-3
-------
indicate the maximum vehicle count occurred in the period
10:15 a.m. to 6:15 p.m. Since the count was conducted only
between 7 a.m. and 7 p.m., eight-hour maximum VMT cannot be
established as a percent of 24-hour VMT.
Based on these sources for Chicago, the eight-hour maximum VMT
was approximately 48 percent of the 24-hour average weekday VMT. The
maximum eight-hour period varied in different parts of the city: In the
CBD, it appeared to be from 10:15 a.m. to 6:15 p.m., while for the city as
a whole, it appears to be from 12 noon to 8 p.m.
3.2.1.2 Meteorological Data
Seasonal average wind speeds and directions were obtained from
National Climatological data charts. It should be noted that these
averages represent typical cases for the area and are applied only to give
representative samples of the possible dispersion patterns for the area.
3.2.1.3 Stationary Sources
No detailed stationary source data were available for Chicago. EPA
supplied estimates of the precentage of total emissions due to stationary
sources within the region. These percentages were applied to the calculated
mobile source emissions to obtain an estimate of the total emissions per
grid. Estimates of the impact of projected stationary source controls were
*
supplied by the Department of Environmental Control. The most significant
change is a 20-percent reduction in total hydrocarbon emissions expected
by 1977.
3-4
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3.2.2 Summary of Results
The following discussion presents the impact of the transportation
controls on each of the three pollutants considered. Figure Chi.l shows
the analysis area.
3.2.2.1 Carbon Monoxide
Table Chi.l summarizes the maximum emissions and maximum concentra-
tions predicted for carbon monoxide for each of the applied control strategies
and the uncontrolled cases. The maximum concentrations predicted are given
for the "worst case" which is defined by a wind speed of 2.5 meters/second.
The areas of maximum CO emissions and concentrations are all associated with
major intersections along .the JFK Expressway. (See.Figure Chi.2.) The
grid of absolute maximum emissions or concentrations varies from case to
case due to the effects of the detailed data supplied. (See Section 3.2.1.)
Stationary sources are treated as background emissions as described
in Section 3.2.1.3 due to lack of detailed source data. This procedure
would tend to understate the effect of a large stationary source in an
area of low vehicular emissions and to overestimate the stationary emissions
in an area of high vehicular emissions. For CO emissions, the deviation
from realistic conditions is minimal because mobile sources represent
approximately 96 percent of the total CO emissions for the Chicago region.
The impact of this procedure on the dispersion patterns is to make them
more representative of mobile sources. This may be helpful in visually
comparing the effect of individual strategies on the base year patterns.
The 1977 predictions show the effect of emission control devices
only on the maximum eight-hour and peak-hour concentrations. The 1968
maximum emissions would be reduced by nearly three quarters bringing the
predicted 1977 concentrations below federal standards. Maintenance of
this level of reduction is dependent upon the deterioration of the control
device efficiency as explained in Section 2.4. An inspection and maintenance
program would maintain this level of reduction and reduce mobile source CO
emissions an additional 10 percent as shown in Strategy 1.
3-5
-------
CARBON MONOXIDE
1968
1977
Strategy 1
Strategy 2
Strategy 3
MAXIMUM EMISSIONS
(tons/year)
Total
30582 (917)*
9853 (821)
9019 (821)
9443 (821)
8292 (821)
Mobile
28748 (917)
8362 (821)
7528 (821)
7952 (821)
6801 (821)
MAXIMUM CONCENTRATIONS
(mg/m3)( Worst Case)
8 Hr
32.5 (917)
8.9 (821)
8.1 (821)
8.5 (884)
7.4 (821)
1 Hr
58.8 (917)
15.9 (821)
14.5 (821)
15.0 (1010)
13.0 (821)
NITROGEN OXIDES
1968
1977
Strategy 3
MAXIMUM EMISSIONS
(tons/year)
Total
2095 (821)
1405 (821)
1371 (821)
Mobile
1362 (821)
735 (338)
638 (821)
MAXIMUM CONCENTRATIONS
(yg/m3)( Worst Case)
8 Hr
1800 (821)
1100 (821)
1100 (821)
1 Hr
2200 (821)
1400 (821)
1300 (821)
*The numbers which appear in parentheses represent the grid numbers in which
the maximum occurs. See Figures Chi.2, Chi.3, and Chi.4 for location of
these maxima for CO, HC, and NO , respectively.
/\
Table Chi.l. Predicted Maximum Emissions and Concentrations
3-6
-------
2049
2017
1985
1953
1921
1889
1857
1825
1793
1761
1729
1697
1665
1633
1601
IS69
IS37
1305
1473
1441
1409
1377
1345
1313
1281
1249
1217
MBS
1153
1121
1089
1057
1025
993
961
929
897
865
833
801
769
737
705
673
641
609
577
545
513
481
449
417
385
353
321
289
257
225
193
161
129
97
65
33
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Figure Chi',1. Chicago Grid Network
3-7
-------
Transportation Condition
1968 Uncontrolled
1977 Uncontrolled
Strategy 1
Strategy 3
Strategy 2 (Eight Hour Only)
Strategy 2 (One Hour Only)
LAKE COUNTY
COOK COUNTY
UCOOK.COUNTY.
DU RAGE COUNTY I lO'HARE
AIRPORT
__
WILL COUNTY j
Figure Chi.2.
Maximum CO Concentration Locations for
Each Transportation Condition Given in Table Chi.l
3-8
-------
Strategy 2 (Traffic Flow Control) would, in effect, increase the
traffic speeds in the central areas. This would slightly decrease CO
emissions; however, the additional impact on concentration values would
be minimal without additional traffic controls, even this b percent
decrease in emissions would probably disappear within one year due to
induced traffic volume increases.
Strategy 3 (Combined Strategies) shows the result of combining
traffic flow controls (Strategy 2), vehicle restraints (5 percent VMT
reduction), and inspection and maintenance (10 percent CO emission
reduction). The prediction assumes full benefit of all strategy
elements would be achieved in 1977. The predicted mobile source emissions
show approximately 20 percent decrease from 1977" uncontrolled estimates.
The resulting eight-hour maximum concentration is well below the federal
standard.
Table Chi.2 summarizes the annual emission totals for each pollutant
for the entire grid area for each transportation controJ condition. These
values can be used for "rollback" calculations for the Chicago area.
3.2.2.2 Hydrocarbons
Table Chi.3 summarizes the maximum emissions and concentrations for
hydrocarbons in the grid area. Figure Chi.3 shows the location of these
maxima. Note that peak-hour concentrations are calculated as opposed to
federal standards for the three-hour (6 - 9 a.m.) time period. Transporta-
tion did not permit computation of concentration corresponding to the
standard time periods. These values have been adjusted to three-hour
(2\
averages using Larsen's modelv ' and ambient data.
R. I. Larsen, "A Mathematical Model for Relating Air Quality Measurements
to Air Quality Standards," November 1971, Office of Air Programs
Publication No. AP-89.
3-9
-------
CO
I
TRANSPORTATION
CONDITIONS
1968
1977 (uncontrolled)
Strategy 1
Strategy 2
Strategy 3
CARBON MONOXIDE
Total
3880155
1649731
1504713
1575066
1381365
Mobile
3647420
1412249
1271585
1341973
1148202
HYDROCARBONS
Total
691634
279902
258931
272682
243556
Mobile
560204
174758
153787
167538
138412
NITROGEN OXIDES
Total
295729
226647
NA
NA
215466
Mobile
192254
119861
NA
NA
111709
Table Chi. 2. Annual Emissions (tons/year) for the Area Shown in Figure Chi. 1.
-------
HYDROCARBONS
1968
1977
Strategy 1
Strategy 2
Strategy 3
MAXIMUM EMISSIONS
(tons /year)
Total
4929 (917) 1
1896 (821)
1773 (821)
1859 (821)
1686 (821)
Mobile
3992 (917)
1026 (821)
903 (821)
989 (821)
816 (821)
MAXIMUM CONCENTRATIONS
(vg/m3) (Worst Case)
8 Hr
5100 (917)
1500 (917)
1000 (917)
1500 (917)
400 (821)
1 Hr
8300 (917)
2300 (821)
1500 (821)
2200 (821)
600 (821)
3 Hr2
5200 (917)
1500 (917)
1000 (917)
1500 (917)
400 (821)
3 Hr3
6700 (917)
1800 (821)
1200 (821)
1800 (821)
500 (821)
xThe numbers which appear in parentheses represent the grid numbers in which the maximum occurs.
Figures Chi. 2, Chi. 3, and Chi. 4 for location of these maxima for CO, HC, and NOV, respectively.
J\
2Based on conversion of predicted concentration for eight-hour average by Larsen's method.
3Based on conversion of predicted concentration for one-hour average by Larsen's method.
See
Table Chi.3. Predicted Maximum Emissions and Concentrations
-------
Transportation Condition
1968 Uncontrolled
1977 Uncontrolled (Eight Hour Only)
Strategy 2 (Eight Hour Only)
1977 Uncontrolled (One Hour unly)
Strategy 2 (One Hour Only)
Strategy 3
LAKS. COUNTY
COOK COUNTY
Figure Ch1.3.
Maximum HC Concentration Locations for Each
Transportation Condition Given 1n Table Chi.l
3-12
-------
Hydrocarbon concentrations and emissions are affected by stationary
source emissions to a greater extent than CO concentrations as can be seen
in Table Chi. 3. Again, the treatment of stationary sources as a background
tends to minimize the possible impact of large stationary sources and
possibly overstate the contribution from stationary sources in many outlying
areas containing major transportation arteries. It may therefore be more
appropriate to consider the relative reduction in mobile source emissions
rather than resultant concentrations for the purpose of analyzing the impact
of transportation controls.
The 1977 uncontrolled mobile emissions show a reduction of approximately
73 percent over 1968 emissions for hydrocarbons. This reduction due to
internal automotive controls only may be sufficient, to meet federal standards
if the major stationary sources are controlled. Since some stationary
sources controls are expected to be in effect by 1977 in Chicago, the
federal standard should be met; however, the predicted concentrations do
not support this. An inspection and maintenance program could be expected
to maintain the reductions achieved by new car standards and to give an
additional 12 percent reduction in hydrocarbon mobile source emissions as
shown by Strategy 1.
Traffic flow control (Strategy 2) would reduce the maximum 1977
emissions by less than 5 percent, and applied alone this strategy would
have very little lasting impact on concentrations. However, in combination
with some form of vehicle restraints (Strategy 3), an additional 8 to 10
percent reduction in hydrocarbon emissions from mobile sources could be
realized.
3-13
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3.2.2.3 Oxides of Nitrogen
Table Chi.l summarizes the maximum concentrations and emissions for
NOX in the grid area. Figure Chi.4 shows the location of these maxima for
each transportation control condition. It can be seen from the table that
the predicted maximum concentrations are grossly affected by stationary
sources for which no control is expected by 1977. For the purpose of
analyzing the impact of transportation controls, it may be more appropriate
to consider the relative reduction in mobile source emissions rather than
resultant concentrations.
The 1977 uncontrolled mobile emissions show approximately 45 percent
reduction over 1968 emissions. Whether this reduction value would be
sufficient to bring actual air quality within federal guidelines is not
clear from the predicted values.
Strategy 3 (Combined Emission and Traffic Controls) is the only
transportation control strategy with a direct impact on NOX emissions.
The approximately 15 percent decrease in NOV emissions over 1977 uncontrolled
/\
emissions is a result of reduced VMT due to vehicle restraints.
Table Chi.2 lists the predicted annual emissions for NOX for the
entire grid network for each transportation control condition. Both total
emissions and mobile source emissions are given. The annual emissions from
this table can be used for "rollback" calculations.
3-14
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Location Transportation Condition
Conditions
LAKE COUNTY /
COOK COUNTY
Figure Ch1. 4. Maximum NOx Concentration Location for Each
Transportation Condition liiven In Table Chi.l.
Figure Chi. 4. Maximum NOx Concentration Locations for
Each Transportation Condition Given in
Table Chi.l.
3-15
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3.3 METROPOLITAN AREA ANALYSIS - NEW YORK
3.3.1 Data Base and Methodology
3.3.1.1 Transportation Data
0 Basic Data
Basic data were provided by a number of cooperating agencies,
especially the Tri-State Regional Planning Commission, The Transportation
Planning Division of the New York City Planning Commission and the Port
of New York Authority. Specifically, the following key items were obtained
from the Tri-State Transportation Commission:
a. Vehicle miles traveled for 1970-1977 for each of
127 analysis areas
(1) By type of roadway
(2) Average operating speeds
(3) Estimated speeds for 1977
(4) Average volume per lane
b. Vehicle registrations
c. Model for highway needs evaluation
d. Hourly vehicular traffic by type.
e. Flow and volume maps of the region.
The New York City Planning Commission provided the following
additional inputs:
a. Traffic Department vehicle counts from the
Annual Cordon Survey for 1965-1971.
b. Tunnel and river counts for 1965-1971.
c. Twenty-four hour counts by one-hour sequences for
major corridors.
d. Vehicle population for New York City, 1965-1971.
• Disaggregation of New York City Data
As noted elsewhere in this report, the analysis focused on the
CBD peak-hour traffic. In New York City, the initial VMT data provided
3-16
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information classified into only three "Analysis Areas" for all of the
Borough of Manhattan.
These relatively large Analysis Areas' 1977 VMT did not provide
consistent emission results — e.g., New York City for 1970 calculations
fell-below Federal standards. In order to develop data which would more
accurately reflect variations in the concentration of VMT, Tri-State
provided 1963 VMT data broken down into square mile units. This provided
a basis for disaggregating the three Analysis Areas covering Manhattan into
approximately 30 areas. Similar disaggregations were possible for the
other Analysis Areas including Manhattan, Bronx, Brooklyn, Queens, and
Richmond Counties in New York and Hudson and Bergen Counties in New Jersey.
Calculation of Manhattan VMT based on these revised square mile
data indicated a total of 5,668,820 VMT in 1963 (based on 1964-1965 24-hour
weekday traffic counts). This compared to 6,035,850 VMT for 1970 and
6,402,877 VMT for 1977 projections shown by the Tri-State printouts. Con-
versations with Tri-State indicated that the 1963 square mile VMT of
5.67 million was consistent with their 1970 and 1977 forecasts for Man-
hattan and were advised that no adjustments would be required in the VMT
printouts for 1970 and 1977.
A final step in the disaggregation process involved the distribu-
tion of 1970 and 1977 VMT into a square mile distribution. Because no
square mile data were available to the project for the period after 1963,
both 1970 and 1977 VMT were distributed on the same percentage basis as
the 1963 VMT square mile data. Though this introduced error in the
distribution of VMT for both 197p and 1977, we were advised by Tri-State
that the error was relatively small -- e.g., the relative VMT was not
substantially different between 1963 and 1970. Unfortunately, the errors
introduced had to be accepted since no alternative data were available
and all analysis for New York would have had to be eliminated. However,
it is quite obvious that land uses have changed in Manhattan since 1963
and some differences in VMT distributions have undoubtedly occurred.
3-17
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The specific methodology used is enumerated below:
1. The percentage distribution of VMT by square mile was
calculated for each Analysis Area to be included in our
model. This included a 20-mile square region covering
New York and New Jersey.
2. The percentage contribution of each square mile to the
total VMT in each Analysis Area was calculated for 1963
and then applied to 1970 and 1977 VMT for each Analysis
Area.
3. The use of 1963 VMT percentage distributions per square
mile for 1970 VMT clearly does not incorporate changes in
land uses and trip-making since 1963. The application of
1963 square mile distributions to 1977 data, of course,
further compounds the error. However, the error will be
somewhat confined in view of the fact that the VMT pro-
jections by Analysis Areas for 1970 and 1977 themselves
take into account the shifts in land use and travel. (For
example, the Analysis Areas comprising Richmond show sub-
stantial growth in relation to the Manhattan
Analysis Areas between 1970 and 1977.) In Analysis Areas
4 through 7 (The Bronx), VMT between 1970 and 1977 increased
by about 4.51 percent (from 5.45 to 5.70 million). This
total is disaggregated (by Tri-State) into each of the
separate Analysis Areas 4 through 7 and each Analysis Area
has a different rate of growth (reflecting the difference
in the projected travel expected). The VMT for 1970 and
1977 may be considered reliable in that they reflected the
assumptions and conclusions postulated by the regional
transportation planning agency.
New error is introduced when the 1963 percentage distribu-
tions of VMT per square mile are applied to each of the
Analysis Areas. However, without data on changes in land
use, floor space or some other variable related to trip-
making, there was no way to correct the error.
• Estimation of VMT by Vehicle Type: 1977
Because of the importance of trucks in New York City VMT,
estimates of the split between light and heavy duty vehicle VMT was made.
The procedure used is described below:
1. Total 1963 VMT for each borough was obtained from the NYC
Draft Air Pollution Plan (NYAP). (These VMT had been
obtained by New York City from the Tri-State Regional
Planning Commission Report, Streets and Highways: A
Regional Report, January 19687]"""
3-18
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a. Bus data was obtained from NYAP which calculated diesel
(D) and gasoline (G) bus mileages on the basis of data
from the Transit Authority.
b. Fleet medallion, non-fleet medallion, and non-medallion
cab mileages were calculated by NYAP on the basis of
discussions with the Taxi Commission.
c. Truck mileage was calculated from figures provided by
the Tri-State Commission. Airline mileage was multiplied
by 1.25 to provide an estimate of actual mileage. For
the Manhattan breakdown, it was assumed that NYAP
percentage distribution held -- e.g., that 84.1 percent
of all Manhattan truck mileage took place in Analysis
Area 001. It is also assumed by NYAP that one-sixth
of truck mileage is diesel (D) and the rest is gasoline
(G).
d. Automobile mileage was calculated as a residual.
2. 1970 VMT was projected from the 1963 VMT estimates as
follows:
a. Total 1970 VMT, bus VMT and truck VMT were projected
by the same ratio (for each borough) as the increase in
bridge and tunnel crossings computed by NYAP. (Note:
The NYAP adjusted downward the Richmond [Staten Island]
increase, and this adjustment was accepted.)
b. Taxi mileage was assumed to remain unchanged.
c. Automobile mileage was calculated as a residual.
d. The vehicle split was obtained for each borough by
calculating the percent mileage for each vehicle type.
3. 1977 VMT was projected from the 1963 and 1970 VMT estimates
as follows:
a. Total 1977 VMT, bus, taxi, truck, and auto VMT were
projected from 1970 VMT estimates by the 1963 to 1970
VMT ratio.
b. The vehicle split was obtained for each borough by
calculating the percent mileage for each vehicle type.
i .-.---
t Speed Factors
Though the New York City data on speed provided by the Tri-State
Regional Planning Commission were appropriate for average speed during the
eight-hour maximum VMT period, they were not considered applicable for the
one-hour peak VMT period. Based on journey-to-work data from the 1963
Home Interview Survey, the Tri-State Regional Planning Commission developed
a series of relationships for travel to the Manhattan CBD. Specifically,
3-19
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four modes were selected: auto driver, railroad, subway and commercial
bus. The inbound peak period was set as 7 a.m. to 9:59 a.m. -- these three
hours comprising 84 percent of the journey-to-work travel. The remaining
21 hours of the day were defined as the off-peak period.
Using the findings of the Tri-State analysis, it was possible to
develop speed zones similar to those used in the Washington, D. C.,
analysis. These peak-hour speeds were expressed in miles-per-hour and
were related to trip distance with trip distance measured in airline miles
and time expressed on a door-to-door basis including walking. Though some
error exists in time estimates (since there may be some walking distances
after arrival at work that would result in somewhat longer time of travel),
these are not considered to be significant for purposes of the analysis.
Based on our analysis, the following speed adjustment factors were applied
to appropriate analysis areas as related to distance from the CBD:
Table 3.3-1 . Speed Adjustment Factors for the
New York Region by Distance From
CBD
Distance
Segment
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
24
Ratio of Peak
to Off-Peak
50%
67
75
78
79
80
80
81
82
83
84
85
85
85
86
87
88
89
90
91
92
Hour Speed
Hour Speed
3-20
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• Peak-Hour and Eight-Hour Maximum VMT Periods
Base major bridge and tunnel crossings hourly data were analyzed
to estimate the peak one- and eight-hour periods of VMT. From these
analyses it was estimated that the eight-hour peak VMT period accounts for
46.3 percent of the 24-hour VMT; the one-hour peak accounted for 7.8 per-
cent of the 24-hour total VMT. These factors were used in developing the
one- and eight-hour data for analysis zones in New York City.
3.3.1.2 Meteorological Data
National climatological charts were used to obtain seasonal averages
for wind speed and direction. It should be noted that these averages are
used to represent typical cases for the area and are applied only to give
representative samples of the possible dispersion patterns for the area.
3.3.1.3 Stationary Sources
County data were available for New York giving the 1970 and 1977 emissions
for each pollutant due to stationary sources. These county totals were
apportioned to the grid areas using the VMT for each grid as an apportion-
ing factor.
3-21
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3.3.2 Summary of Results
The following discussion presents the impact of the transportation
controls on each of the three pollutants considered. Figure N.Y.I shows
the analysis area.
3.3.2.1 Carbon Monoxide
Table N.Y.I summarizes the maximum emissions and maximum concentra-
tions predicted for carbon monoxide for each of the applied control
strategies and the uncontrolled cases. The maximum CO concentrations shown
in the table are associated with major expressway and tunnel areas near
the tip of Manhattan. Other areas of high concentration include two areas
on the New Jersey shore both associated with major expressway or tunnel
intersections, Central Manhattan, and a strip between the Bronx and
Queens which appears to be a result of the expressway system connecting
the two airports.
Stationary source data in New York were given on a county basis
and were distributed among the individual grids using VMT per grid as the
apportioning factor. By applying these stationary source emissions as a
background varying with vehicular emissions, the mobile source emission
distribution pattern is retained and predicted concentration values should
be more realistic. The maximum concentration values given in Table N.Y.I
indicate that current eight-hour values are above the federal standards.
The projected 1977 values for these same time periods suggest that the
peak-hour values will be easily controlled by the direct application of
automotive control devices. Maximum eight-hour values are predicted to
be below the federal standard for the "worst case" considered.
The projected 1977 mobile source emissions could be reduced by
approximately 10 percent by the introduction(of an inspection and
maintenance program (Strategy 1) in the metropolitan area. This program
would also insure the reduction achieved by new car standards are not
deteriorated.
3-22
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Figure N.Y.I New York Grid Network
Total Area - 400 mi'
Grid Area - 1 mi2
3-23
-------
CARBON MONOXIDE
1970
1977
Strategy 1
Strategy 2
Strategy 3
MAXIMUM EMISSIONS MAXIMUM CONCENTRATIONS
(tons/year) (mg/m3) (Worst Case)
Total
20244 (134)*
7388 (134)
6671 (134)
7301 (134)
5953 (134)
Mobile
19425 (134)
7192 (134)
6475 (134)
7105 (134)
5757 (134)
8 Hr
19.9 (134)
7.4 (134)
6.7 (134)
7.3 (134)
6.0 (134)
1 Hr
32.2 (134)
11.7 (134)'
10.6 (134)
11.6 (134)
4 (134)
NITROGEN OXIDES
1970
1977
Strategy 3
MAXIMUM EMISSIONS MAXIMUM CONCEdTKATIUNS
(tons/year) (yg/m3j (Worst lase)
Total
9064 (134)
4898 (134)
4710 (134)
Mobile
2622 (134)
1880 (134)
1692 (134)
8 hr
6800 (134)
3800 (134)
3700 (134)
1 hr
7500 (134)
4400 (134)
4200 (134)
*The numbers which appear in parentheses represent the grid numbers in
which the maximum occurs. See Figure N.Y.2 for location of these
maxima for CO, HC, and NOY, respectively.
Table N.Y.I. Predicted Maximum Emissions and Concentrations
3-24
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Strategy 2 (Traffic Flow Controls) appears to be slightly effective
for the New York area. The slight improvement in mobile emissions can be
attributed to the increased average vehicle speed implied by this strategy.
If this strategy is applied without further vehicle restraints, however,
any improvement in emissions may be quickly degenerated by the effects
of induced traffic volume due to the implied flow improvement.
The reduction in emissions and resultant CO concentrations attributed
to the combined strategies (Strategy 3) is greater than the reduction of the
individually applied strategies shown in the table. The additional reduction
is a result of the reduction in VMT which would occur if vehicle restraints
are applied to maintain the level of traffic flow improvement suggested
by Strategy 2.
Table N.Y.3 summarizes the annual emission totals for the entire
grid network for each transportation control condition. These values can
be used for "rollback" calculations for the New York area.
3.3.2.2 Hydrocarbons
Table N.Y.2 summarizes the maximum HC concentrations and emissions
predicted for the grid area. Figure N.Y.2 shows the location of these
maxima for each transportation control condition. The total emissions
shown in the table reflect the importance of stationary hydrocarbon sources
in the New York area. The impact of these sources increases as the mobile
source emissions are decreased. For the purpose of analyzing the impact
of transportation controls, it may be more appropriate to consider the
relative reduction in mobile source emissions rather than the resultant
concentrations.
Mobile source hydrocarbons are predicted to decrease by approxi-
mately 44 percent by 1977 due to the emission control devices required by
the Federal new source standards. This reduction could be maintained and
an additional 12 percent reduction in 1977 mobile emissions achieved by an
inspection and maintenance program (Strategy 1).
3-25
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Figure N.Y.2. Maximum Concentration Location for All
Pollutants for All Conditions Listed
in Tables N.Y.I and N.Y.2.
3-26
-------
CO
I
ro
HYDROCARBONS
1970
1977
Strategy 1
Strategy 2
Strategy 3
MAXIMUM EMISSIONS
(tons/year)
Total
4451 (134)1
"2609 (134)
2364 (134)
2588 (134)
2169 (134)
Mobile
3610 (134)
2031 (134)
1768 (134)
2010 (134)
1591 (134)
MAXIMUM CONCENTRATIONS
(yg/m3) (Worst Case)
8 Hr
4200 (134)
2400 (134)
2100 (134)
2300 (134)
1900 (134)
1 Hr
6300 (134
3500 (134)
3100 (134)
3400 (134)
2800 (134)
3 Hr2
4400 (134)
2500 (134)
2200 (134)
2400 (134)
2000 (134)
3 Hr3
7600 (134)
4200 (134)
3700 (134)
4100 (134)
3400 (134)
numbers which appear in parentheses represent the grid numbers in which the maximum occurs.
Figure N.Y.2 for location of these maxima for CO, HC, and NO , respectively.
/\
2Based on conversion of predicted concentration for eight-hour average by Larsen's method.
3 Based on conversion of predicted concentration for one-hour average by Larsen's method.
See
Table N.Y.2. Predicted Maximum Emissions and Concentrations
-------
ro
oo
TRANSPORTATION
CONDITIONS
1970
1977 (uncontrolled)
Strategy 1
Strategy 2
Strategy 3
CARBON MONOXIDE
Total
1262410
553098
504370
547056
456064
Mobile
1164965
482900
434172
476858
385866
HYDROCARBONS
Total
306877
159741
151661
159022
145125
Mobile
208599
67735
59655
67016
53119
NITROGEN OXIDES
Total
333684
209057
NA
NA
202373
Mobi 1 e
94285
66844
NA
NA
60160
Table N.Y. 3. Annual Emissions (tons/year) for the Area Shown in Figure N.Y. 1.
-------
The extremely low average vehicle speeds in major portions of the
metropolitan area during peak traffic hours result in very high emission
rates. Strategy 2 (Traffic Flow Control) is slightly effective in reducing
hydrocarbon emissions by increasing the average speeds in these congested
areas. An approximately 11 percent reduction in mobile source emissions is
achieved by application of this strategy to the projected 1977 data base.
Strategy 3 (Combined Strategies) provides the vehicle restraints
necessary to maintain the level of traffic flow control achieved.by
Strategy 2. VMT reduction may be achieved by the implementation of
vehicle restraints and this would provide an additional 10 percent (approxi-
mately) reduction in mobile source hydrocarbon emissions.
Table N.Y.3 lists the predicted annual hydrocarbon emissions for
the entire grid network. The emissions in this table can be used for
"rollback11 calculations.
3.3.2.3 Oxides of Nitrogen
NO emissions and maximum concentrations in the grid area are
A
shown in Table N.Y.I. Figure N.Y.2 shows the location of the maximum
concentration for each of the transportation control conditions considered.
It can be seen from the table that the maximum concentrations are grossly
affected by stationary sources for which no control is expected by 1977.
For the purpose of analyzing the impact of transportation controls, it may
be more appropriate to consider the relative reduction in mobile source
emissions rather than resultant concentrations.
The 1977 uncontrolled mobile emissions show a reduction of approxi-
mately 28 percent over base year mobile source emissions. This reduction
is the result of automotive controls expected to be installed.
Whether this reduction in mobile sources will be sufficient to produce
any major reduction in ambient concentrations will depend on the impact
of stationary source emissions on the concentrations which cannot be
adequately described with this model.
3-29
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Table N.Y.3 lists the predicted annual emissions for NOX for the
entire grid network for each transportation control condition. Both total
and mobile source emissions are given. The annual emissions from this
table can be used for "rollback" calculations if desired.
3-30
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3.4 METROPOLITAN AREA ANALYSIS - DENVER
3.4.1 Data Base and Methodology
3.4.1.1 Transportation Data
• Basic Data
Basic data were provided by the Colorado State department of
Highways and consisted of vehicle miles traveled and speed data for the
156 districts comprising the Denver Metropolitan area. The oata covered
annual average weekday travel in 1969 and 1990. It was part of the 1970
Denver Urban Impact Study and represented travel within a line defined
as the "urban-in-fact" boundary for January 1, 1970, and included tne
developed fringe of the Denver urbanized area.
Also provided was information on travel on city streets. The
Colorado Highway Department estimated approximately 8bO,000 VMT in I9b9
on local streets and indicated it probably should be about equally dis-
tributed among each of the 156 districts. The local street VMT estimate
for 1990 was 1.34 million miles of vehicle travel. The speea for uoth
1969 and 1990 for local street VMT was assumed to oe 17 mph.
Speed data were based on the Speed Report for tne 1970 troffic
assignment model showing speed data by functional class and area, (dasic
raw material provided from DRCOG^3' 1970 Travel Time Study)
• Interpolation Factors
The interpolation procedure used in obtaining 1977 VMT for each
district may be summarized as follows:
1977 VMT = A [1969 VMT + B(1990 VMT - 1969 VMT)]
Explanation for "B"
"B" is an interpolation factor based on ORCOG "Population Estimates
and Projections: 1970 Census Tracts - Denver SMSA, 1968-1975-
1990-2010." For each district,
^'Denver Kegional Council of Governments.
3-31
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n _ Percent increase in population from 1969 to 1977
Percent increase in population from 1969 to 1990
Explanation for "A"
The DRCOG "Population Estimates and Projections" utilized were
interpolated in the aoove manner to estimate 1970 population
by district. Actual population figures provided oy the 1970
Census were found to differ, in some cases substantially. It
was felt that the VMT projections supplied would be based on
similar information as that utilized in the jRCOG population
projections and, hence, would exhibit similar deviations from
actual experience. In particular, it would appear that variances
in population estimates resulted primarily from unanticipated
changes in migration patterns and that migrants probably tend
to be over-represented as a proportion of population since a
high proportion are employed. Consequently, it was felt that
an adjustment to 1977 VMT should be made reflecting new data
supplied by the 1970 Census. Accordingly, as a rough adjustment,
the 1977 VMT for each district is multiplied by "A", which is
the ratio of 1970 actual population to 1970 estimated population.
• Estimates of Eight- and Peak-Hour VMT and Speed
The estimates of daily traffic variation was based on the following
information:
a. A distribution of appropriate counting stations wnich
showed the 24-hour daily variation based on Interstate
daily count locations and provided the means of deriving
daily one-hour peak and eight-hour peak shares of traffic.
b. Twenty-four hour downtown street traffic variation oased
on manual counts expanded into 10-hour machine controlled
counts (10-minute counts per hour basis for sampling).
Based on these data and using weighted averages, it was estimated
that eight-hour VMT is 53.4 percent of the 24-hour VMT; and the one-hour
maximum VMT revised is 9.3 percent of 24-hour VMT.
Using the URCOG "1970 Travel Time Study" (which provided peak-hour,
a.m. and p.m., and off peak-hour, directional, average speeds), comparisons
were made for three major arteries (Broadway, Colorado, and Federal) between
mean-peak hour and mean off peak-hour speeds. Un the average, (tnough witn
a wide variation) peak-hour speeds were 77 percent of off peak-hour speeds.
3-32
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3.4.1.2 Meteorological Data
Seasonal average wind speeds and directions were obtained from
national climatological data charts. It should be noted that these averages
represent typical cases for the area and are applied only to given representa-
tive samples of the possible dispersion patterns for the area. The Denver
basin is an area as described in Section 2.3 where physical and meteorological
conditions can create high pollution potentials which are not defined by
the model. Therefore, the "worst case" maximum concentrations predicted
may not agree closely with recorded ambient maximums.
3.4.1.3 Stationary Sources
The 1969 and 1977 county total stationary source contributions
for each pollutant were estimated from the Colorado Implementation Plan.
The totals were distributed to the grids within the counties using VMT
as an apportioning factor.
3.4.2 Summary of Results
The following discussion presents the impact of the transportation
controls on each of the three pollutants considered. Figure Den.l shows
the analysis area.
3.4.2.1 Carbon Monoxide
Table Den.l summarizes the maximum emissions and concentrations
predicted for carbon monoxide for each of the applied transportation
conditions. (See Figure Den.2.) This maximum area is surrounded by
several high concentration areas closely associated with major highway
intersections near the city limits.
i
Stationary sources are treated as background emissions as described
in Section 3.4.1.3. This procedure has a very minor effect on CO emissions
because these sources represent only about 1 percent of the total CO
emissions in Denver.
The 1969 or base year estimates shown in Table Den.l predict
current "worst case" conditions exceed the eight-hour maximum federal
standard. By 1977, the model predicts that a 52 percent reduction in
mobile source emissions due to internal automotive controls will bring
the eight-hour maximum levels well within the federal standards.
3-33
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CARBON MONOXIDE
1969
1977
Strategy 1
Strategy 2
Strategy 3
MAXIMUM EMISSIONS
(tons/year)
Total
13394 (288)*
6724 (288)
6095 (288)
6674 (288)
5770 (288)
Mobile
12980 (288)
6279 (288)
5G51 (288)
6229 (288)
5325 (288)
MAXIMUMjCOHCEUTKATIUNS
(mg/m ')( Worst Case)
8 Hr
12.7537 (288)
7.4960 (289)
6.G453 (289)
7.5343 (289)
6.5 (289)
1 Hr
20.1236 (288)
11.0922 (289)
9.9917 (289)
10.9526 (289)
9.4 (288)
NITROGEN OXIDES
1969
1977
Strategy 3
MAXIMUM EMISSIONS
(tons/year)
Total
2947 (288)
3104 (288)
3094 (288)
Mobile
260 (288)
212 (288)
201 (288)
MAXIMUM COlMCtiMTKATIOHS
" (ug/m3) (Worst Case)
8 Hr
1700 (288)
1800 (288)
1800 (288)
1 Hr
1800 (288)
1800 (288)
1800 (288)
*The numbers which appear in parentheses represent the grid numbers in
which the maximum occurs. See Figure Den.2 for location of these
maxima for CO, HC, and NOV, respectively.
/\
Table Den. 1. Predicted Maximum Emissions and Concentrations
3-34
-------
601
576
551
526
501
476
451
426
401
376
351
326
301
276
251
226
201
176
151
126
101
76
51
26
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Figure Den.l. Grid Network
Total Area = 625 mi2
Grid Area = 1 mi2
3-35
-------
1
•OULDER COUNTY 1
i
i
1
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,--
QT 2
•
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Ill
%
/*
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|^'J
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Figure Den.2. Maximum Concentration Location for
AIT Pollutants for All Transportation
Conditions Listed in Table Den.l and
Den.2.
3-36
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An inspection and maintenance program (Strategy 1) would reduce
the predicted 1977 mobile emissions by approximately 10 percent. This
would not have a marked influence on predicted concentrations; however,
it would insure that the automotive emissions did not increase above the
level attributed to emission control devices.
Strategy 2 (Traffic Flow Controls) assumes an average increase
in vehicle speeds. The impact of this strategy would be almost negligible
because of the relatively high average speeds projected for 1977.
The approximately 15 percent reduction in emissions produced by
the combined strategies (Strategy 3) is greater than the sum of emission
reductions from Strategies 1 and 2 because of the .vehicle restraints applied
to maintain the desired level of traffic flow control. These vehicle
restraints will produce an additional small percentage reduction in total
VMT which increases the total effectiveness of this strategy.
Table Den.3 summarizes the annual emissions total for each pollu-
tant for the entire grid network for each transportation control condition.
These values can be used in "rollback" calculation formulas if desired.
3.4.2.2 Hydrocarbons
Maximum hydrocarbon emissions and resultant concentrations predicted
for each transportation condition are given in Table Den.2. Figure Den.2
shows the location of the maximum concentrations listed in the table. The
location of these maxima does not vary from pollutant to pollutant. This
is primarily a result of the treatment of stationary sources as background
( _ - -
emissions. Since these sources vary directly with the mobile source
strength, the resultant distribution patterns are representative of the
mobile source data although the absolute concentration values are greatly
affected by the stationary source contribution.
3-37
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CO
CO
00
HYDROCARBONS
1969 m
1977
Strategy 1
Strategy 2
Strategy 3
' MAXIMUM EMISSIONS
(tons/year)
Total
4496 (288)1
3733 (288)
3655 (288)
3728 (288)
3622 (288)
Mobile
1633 (288)
648 (288)
570 (288)
644 (288)
538 (288)
MAXIMUM CONCENTRATIONS
(ng/m3) (Worst Case)
8 Hr
3100 (288)
2300 (288)
2200 (288)
2300 (288)
2200 (288)
1 Hr
4000 (288)
2600 (288)
2500 (288)
2600 (288)
2500 (288)
3 Hr2
3000 (288)
2300 (288)
2200 (288)
2300 (288)
2200 (288)
3 Hr3
3100 (288)
2400 (288)
1900 (288)
2000 (288)
1900 (288)
:The numbers which appear in parentheses represent the grid numbers in which the maximum occurs.
Figure Den.2 for location of these maxima for CO, HC, and NO , respectively.
^
2Based on conversion of predicted concentration for eight-hour average by Larsen's method.
3Based on conversion of predicted concentration for one-hour average by Larsen's method.
See
Table Den.2. Predicted Maximum Emissions and Concentrations
-------
The 1977 uncontrolled mobile source hydrocarbon emissions are
reduced by approximately 60 percent over base year (1969) emissions by
required Federal automotive controls. An inspection and maintenance
program suggested by Strategy 1 would insure the efficiency of automotive
control devices and yield an additional 12 percent reduction in 1977
mobile hydrocarbon emissions.
Strategy 2 (Traffic Flow Controls) would reduce 1977 mobile source
emissions by less than one percent. This strategy would probably have a
negligible effect on concentration values unless combined with extensive
vehicle restraints.
The combined traffic flow control and vehicle restraints suggested
in Strategy 3 would reduce 1977 mobile source (uncontrolled) emissions by
approximately 17 percent. Part of this reduction is attributable to a
small percentage VMT reduction resulting from vehicle restraints.
Table Den.3 summarizes the predicted total annual emissions for
the entire grid network. The hydrocarbon emissions given in this table
can be used for "rollback" calculations if desired.
3.4.2.3 Oxides Of Nitrogen
Table Den.l summarizes the maximum concentrations and maximum
emissions for NOX in the grid area. Figure Den.2 shows the location of
the maximum concentrations. It can be seen from the table that predicted
concentrations values are grossly affected by stationary source contribu-
tions. For the purpose of analyzing the impact of transportation controls,
it may be more appropriate to consider the relative reduction in mobile
source emissions rather than the resultant concentrations.
The 1977 uncontrolled mobile source emissions show approximately
a 18 percent reduction over 1969 emissions.
3-39
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CO
Ja.
O
TRANSPORTATION
CONDITIONS
1970
1977
Strategy 1
Strategy 2
Strategy 3
CARBON MONOXIDE
Total
405682
335516
303189
332296
285898
Mobile
394666
323109
290783
319890
273491
HYDROCARBONS
Total
83400
70597
66554
70291
64820
Mobile
50562
33584
29539
33277
27806
NITROGEN OXIDES
Total
53469
61947
NA
NA
61355
Mobile
8998
11852
NA
NA
11260
Table Den. 3. Annual Emissions (tons/year) for the Area Shown in Figure Den. 1.
-------
Strategy 3 (Combined Strategies) is the only transportation control
strategy with a direct impact on NOx emissions. The approximate 5 percent
reduction in mobile source emissions over 1977 uncontrolled emissions is
a result of a small percentage VMT reduction due to vehicle restraints.
3-41
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3.5 METROPOLITAN AREA ANALYSIS - SAN FRANCISCO
3.5.1 Data Base And Methodology
3.5.1.1 Transportation Data
• Basic Data
The Metropolitan Transportation Commission of the San Francisco
Bay Area provided basic VMT and speed information used for the analysis.
The following data were provided in the form of computer printouts for the
1965 "G" Network (existing system) and the 1980 "X" Network (committed
highways and transit):
a. Node location list and maps.
b. Loaded link volumes, distance, and speed.
c. Trip end table by zone.
d. Vehicle mile summary (by county)
From these data, estimates of zonal VMT and speed were devel-
oped. Because the VMT and speed data were only given by link (approximately
2000 links), zonal estimates had to be developed.
In addition to the above data, additional items of information
were provided as regards employment (and projections to 1990), modal splits,
traffic forecasts and screen!ine counts. The latter data were used for
calculation of the one- and eight-hour peak VMT periods.
• Estimating VMT by Zones
The estimates for each of the 291 zones in the San Francisco
area for 1965 and 1980 were obtained as follows:
1. Trip end summaries for 1965 and 1980 provided Origination/
Productions, Destination/Attractions and Intrazonal trips?
for each zone. All these trip ends were summed and the /
total trips for each zone were divided by the grand total
of all trips for all zones to obtain for each zone the
percent of total. The percent trips for zones were then
summed into counties to give the percent trips for each
county.
3-42
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2. Using total vehicle miles (VMT) available by county for
1965 and 1980, the VMT for each zone was estimated as:
7fUiF VMT - COUNTY VMT x % TRIPS BY ZONE
v ' % TRIPS BY COUNTY
3. Because no relevant information was available for inter-
mediate years, a linear interpolation for each zone
was used to obtain estimates of 1970 and 1977 VMT from
1965 VMT.
In connection with this approach, it should be noted that this
method does not permit accurate distribution of the VMT (trips) between
zones especially between two widely separate zones. However, lack of
available alternate data for link totals (within the time constraints and
costs of the project) did not permit totalling lijiks for each zone. Con-
versations with representatives of the California Highway Department
indicated that the method used above would not introduce serious error,
especially in view of the fact that VMT was to be used as a zone average,
in any case, rather than a zone-to-zone measure.
• Estimating Eight- and One-Hour Maximum VMT
Hourly traffic data for 24 hours were unavailable for most of
the San Francisco region (within the time limits set by the project). How-
ever, traffic counts were available for two major gateways (the Caldecott
Tunnel and the Bay Bridge Toll Plaza) for the spring of 1970 and 1971. ;
Based on these data, hourly distribution percentages were calculated. These
distributions were then related to 12-hour cordon counts, and estimates
were devised for the one- and eight-hour VMT. The results were as follows:
t
•;. =-':-••'.:• One-Hbur peak VMT as'a percent of the 24-hour total - 10 percent.
Eight-Hour peak VMT as a percent of the 24-hour total 50 per-
cent.
3-43
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• Estimating Zone Speeds
The computer printouts provided by the Highway Department of
California provided no zonal speed data -- only link speeds. In order to
estimate zone speeds to be used in the calculation of zonal or grid
emissions, it was necessary to develop an estimating procedure for arriving
at an average speed for each zone. From the printouts, speeds and volumes
were available for 1965 links in the San Francisco area. Approximately
2000 links were designated for the Bay Area Transportation Study (BATS).
If all links were to be used to arrive at a weighted average speed, a
2000 x 2000 link matrix would have had to be used to develop the average
speed and then assigned to almost 300 zones.
Within the time and budget constraints of the project, such an
effort was clearly not possible. Furthermore, time and budget limitations
precluded the possibility of developing a special program to process the
information available on the computer tapes. It was, therefore, necessary
to develop a sampling procedure that would provide representative speed
values.
To do this, the most important links (in terms of volume of
traffic) were identified for all the links included in the printouts.
Staff was assigned to review the volumes on the computer printouts for
1965 data, and key link information was segregated by county along
with speed shown for each of these key links. After an initial list
of key links was developed, it became apparent that additional undivided
arterial and city street data would have to be added and these additional
link speeds and volumes were developed for each of the counties in the
BATS area. Using the estimated link speeds and volumes-iden.t:ifiedMfor;_e_
each county, a weighted average speed was calculated for each county and
this calculated speed value was then assigned to the traffic zones within
the county.
3-44
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A similar procedure was used for both 1965 and 1980 using the
assigned link speeds in both periods weighted by their associated volumes.
The following summarizes the key steps:
1. Identify the key (large traffic volume) links in
each county and plot them on the link maps.
2. Fill out the link data so plotted with additional
links (speed and volumes) for city streets and
undivided arterials (since we found the high
traffic volume links initially plotted to be
mostly freeway).
3. The adjusted link maps were then overlaid with
the zone maps and the speed and volume data
plotted on these zonal maps to assure coverage
in each major county area.
4. The data developed from the above steps were
then put into tabular form and a weighted
average speed was calculated using volumes
as weights.
5. These average speeds were then assigned to
appropriate zones in each county in the BATS
study area.
The table below summarizes the estimated speed values calcu-
lated for major counties by zone for peak-hour, eight-hour, and 24-hour
periods for 1965 and 1980. Description of the steps used for calculating
speed variations in time are included in the following table.
3.5.1.2 Meteorological Data
Seasonal average wind speeds and directions were obtained from
national climatological data charts. It should be noted that these aver-
ages represent typical cases for the area and are applied only to give
representative samples of the possible dispersion patterns for the area.
3.5.1.3 Stationary Sources
1970 and 1977 total stationary source emissions were estimated
from the Implementation Plan for California. These emissions were dis-
tributed throughout the analysis area using VMT as an apportioning factor.
Table S.F.3 shows the impact of these sources on total emissions for 1970
and 1977 for each pollutant.
3-45
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County
Zones
Speed Values (mph)
(inclusive) 24
San Francisco
CBD
All -Other
Mar in
San Mateo
Sonoma
Nap a
Solano
Contra Costa
Santa Clara
Alameda
Steps for
follows :
1-8,39-40
9-38
41-57
58-91
92-101
102-110
111-125
126-160
161-222
223-291
calculating
Calculation 1: 1980
1965
22
49
40
44
38
35
39
48
38
hours
1980
(Calc.l)
21
46
48
48
42
42
42
51
43
48 49
hourly variations
24-hour
Speed
8-hour max.
VMT
1965
(Calc.
21.5
46
34.5
38
32
31.5
32.5
41.5
33.5
1980
3) (Calc
20.5
43
41.5
41.5
35.5
38
35
44
38
42 43
by county and
1-hour
VMT
J965
.3) (Calc.
21
43
29
32
26
28
26
35
29
36
zone were
max.
1980
2:
20
40
35
35
29
34
28
37
33
37
as
a. 1980 24-hour Speed calculated by using Speed and 1980 volumes
b. Using calculations developed for 1965, 1980 Speed values were
substituted for 1965 Speed values whenever they were different
than the 1965 Speed values.
c. The "adjusted speed" (as in "b. above) was weighted by 1980
volumes and a weighted average derived.
Calculation 2: 1965 1-hour Speed
a. Develop factor for 1965 peak hour speed by taking the percentage
ratio: j.980 peak hour speed , no
1980 24-hour speed * ~U
b. Apply this ratio to 1965 24-hour speed values.
Calculation 3; 1965 and 1980 8-hour Speed
a. 1965 and 1980 eight-hour maximum estimated as the mid-point of
the one-hour and 24-hour speed values.
3-46
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3.5.2 Summary of Results
The following discussion presents the impact of these transportation
controls on each of the three pollutants considered. Figure S.F.I repre-
sents the analysis area.
3.5.2.1 Carbon Monoxide
Table S.F.I summarizes the maximum emissions and maximum concen-
trations predicted for carbon monoxide for each of the applied control
strategies and the uncontrolled cases. The areas of maximum concentration
are centered in the city business areas and bridge approaches. (See Figure
S.F.2.) Other high concentration areas include the towns of Oakland and
Richmond.
Stationary sources are treated as background emissions as described
in Section 3.5.1.3. This procedure does not have a critical effect on CO
emissions or concentration patterns in San Francisco because stationary
sources represent a very small percentage of total CO emissions in this
area (approximately 6 percent).
The 1977 predictions given in Table S.F.I show the effect of emission
control devices on the maximum eight-hour and peak-hour concentrations. The
1968 maximum emissions are reduced by 35 percent. This reduction does not
appear to be as great for San Francisco as it is in most of the other major
metropolitan areas considered. The impact of the younger automotive age
distribution is reflected in the predicted 1970 maximum concentrations. The
peak-hour maximum is well below the 40 mg/m3 standard and the predicted
eight-hour maximum barely exceeds the 10 mg/m3 standard. The 35 percent
reduction in emissions by 1977 may" be sufficient to bring the eight-hour
maximum concentration within Federal guidelines without further controls;
however, under severe stagnation conditions (<2.5 meters/second wind speeds)
the eight-hour standard may be exceeded.
3-47
-------
FRANCISCO
SAN MATEO
Figure S.F.I. San Francisco Grid Network
Total Area = 900 mi2
Grid Area = 1 mi2
3-48
-------
CARBON MONOXIDE
1970
1977
Strategy 1
Strategy 2
Strategy 3
MAXIMUM EMISSIONS
(tons/year)
Total
12508 (488)*
9039 (488)
8196 (488)
8512 (488)
7009 (488)
Mobile
11767 (488)
8443 (488)
7600 (488)
7916 (488)
6413 (488)
MAXIMUM CONCENTRATIONS
(mg/m3) (Worst Case)
8 Hr
12.2 (488)
8.5 (488)
7.7 (488)
8.1 (488)
6.6 (488)
1 Hr
20.5 (488)
14.4 (488)
13.0 (488)
12.9 (488)
10.5 (488)
NITROGEN OXIDES
1970
1977
Strategy 3
MAXIMUM EMISSIONS
(tons/year)
Total
1894 (488)
1564 (488)
1451 (488)
Mobile
1245 (488)
1042 (488)
929 (488)
MAXIMUM CONCENTRATIONS
(wg/m^) (Worst oase)
8 Hr
1500 (488)
1200 (488)
1100 (488)
1 Hr
2200 (488)
1800 (488)
1600 (488)
*The numbers which appear in parentheses represent the grid numbers in
which the maximum occurs. See Figure S.F.2 for location of these
maxima for CO, HC, and NOX, respectively.
Table S.F.I. Predicted Maximum Emissions and Concentrations
3-49
-------
% CONTRA COSTA
/
SAN MATEO
K
FRANCISCO
ALAMEDA
Figure S.F.2.
Maximum Concentration Location for
All Pollutants for All Transportation
Conditions Given in Table S.F.I and
S.F.2.
3-50
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An inspection and maintenance program (Strategy 1) would reduce the
predicted 1977 emissions by approximately 10 percent. This would not have
a marked influence on predicted concentrations; however, it would insure
that the automotive emissions do not increase above the level assumed in
the uncontrolled cases, i.e., that the control device efficiency does not
significantly deteriorate.
Strategy 2 (Traffic Flow Controls) assumes an average increase in
vehicle speeds. The impact of this strategy may not be adequately represented
because the speed data base is insufficiently detailed. (See Section 3.5.1.1).
However, it appears that this strategy would have a negligible effect on
concentration values in the Bay Area.
The reduction in emissions produced by the combined strategies
(Strategy 3) is greater than the sum of reductions from the individual
strategies because of the added emission reduction achieved by a small
percentage VMT reduction. This VMT reduction is a result of vehicle
restraints which must be applied to maintain the average vehicle speed
increase provided by the traffic flow controls. The combined emission
reduction would be approximately 20 percent of the 1977 uncontrolled
vehicle emissions and may be sufficient to maintain maximum concentra-
tion values at below standard levels.
Table S.F.3 summarizes the annual emission totals for all pollu-
tants for the entire grid network for each transportation control condition.
These values can be used for "rollback" calculations if desired.
3.5.2.2 Hydrocarbons
Table S.F.2 includes the maximum emissions and concentrations pre-
dicted for each transportation condition for hydrocarbons. Figure S.F.2 shows
the location of the maximum concentrations predicted. The location of this
maximum does not vary from pollutant to pollutant because of lack of detail
in the data base. (See Section 3.5.1.) It should be recalled that stationary
sources are treated as a percentage of the total emissions and, therefore,
vary directly with mobile source emissions. Therefore, although the absolute
3-51
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HYDROCARBONS
1970
1977
Strategy 1
Strategy 2
Strategy 3
MAXIMUM EMISSIONS
(tons/year)
Total
3379 (488)1
2273 (488)
2135 (488)
2220 (488)
1975 (488)
Mobile
1963 (488)
1153 (488)
1015 (488)
1082 (488)
837 (488)
MAXIMUM CONCENTRATIONS
(ug/m )( Worst Case)
8 Hr
2800 (488)
1800 (488)
800 (488)
900 (488)
600 (488)
1 Hr
4100 (488)
2500 (488)
1100 (488)
1200 (488)
900 (488)
3 Hr2
5100 (488)
3300 (488)
1400 (488)
1600 (488)
1100 (488)
3 Hr3
6500 (488)
4000 (488)
1700 (488)
1900 (488)
1400 (488)
ro
*The numbers which appear in parentheses represent the grid numbers in which the maximum occurs.
Figure S.F.2 for location of these maxima for CO, HC, and NOX, respectively.
2
Based on conversion of predicted concentration for eight-hour average by Larsen's method.
3Based on conversion of predicted concentration for one-hour average by Larsen's method.
See
Table S.F.2. Predicted Maximum Emissions and Concentrations
-------
CO
I
en
CO
TRANSPORTATION
CONDITIONS
1970
1977
Strategy 1
Strategy 2
Strategy 3
CARBON MONOXIDE
Total
422100
258594
234294
245519
202029
Mobile
397081
241123
216823
228048
184558
HYDROCARBONS
Total
108384
60468
54176
59085
50141
Mobi 1 e
62983
31461
25169
30078
21134
NITROGEN OXIDES
Total
49891
44317
NA
NA
41582
Mobile
32801
25286
NA
NA
22551
Table S.F. 3. Annual Emissions (tons/year) for the Area Shown in Figure S.F. 1
-------
value of the predicted concentrations is greatly influenced by the
stationary sources which contribute approximately 42 percent of the hydro-
carbon emissions in the Bay Area, the distribution patterns are representative
only of the mobile sources. It should also be noted that the impact of the
stationary source emissions on predicted concentration values increases
markedly as automotive emission control is increased.
The 1977 uncontrolled hydrocarbon mobile source emissions are reduced
by approximately 42 percent over base year (1970) emissions by internal
automotive controls. Whether this reduction would be sufficient to bring
ambient concentration values within Federal guidelines is not apparent
from the model concentration predictions.
An Inspection and Maintenance program suggested in Strategy 1 would
reduce the deterioration of automotive control devices and decrease the 1977
predicted mobile emissions by an additional 12 percent.
Strategy 2 (Traffic Flow Controls) would reduce 1977 mobile source
emissions by less than 5 percent. This strategy would probably have little
effect on concentration values unless combined with extensive vehicle
restraints.
Combined traffic flow control and vehicle restraints suggested for
Strategy 3 would reduce 1977 mobile source emissions by approximately 15
percent. Part of this reduction is attributable to a small VMT reduction
associated with major vehicle restraints.
Table S.F.3 summarizes the predicted total annual emissions for
2
"e 900 mi grid network. The hydrocarbon ei
can be used for "rollback" calculations if desired.
2
the entire 900 mi grid network. The hydrocarbon emissions in this table
3-54
-------
3.5.2.3 Oxides of Nitrogen
Table S.F.I summarizes the maximum concentrations and maximum
emissions for NOX in the grid area. Figure S.F.2 shows the location of
these maxima. It can be seen from the table that the predicted concentra-
tions are grossly affected by stationary sources. For the purpose of
analyzing the impact of transportation controls, it may be more appropriate
to consider the relative reduction in mobile source emissions rather than
resultant concentrations.
The 1977 uncontrolled mobile source emissions show approximately a
16 percent reduction in NO emissions from 1977 uncontrolled emissions. Tlv
A
reduction is a result of required internal automotive controls.
Strategy 3 (Combined Strategies) is the"only transportation control
strategy with an impact on NO emissions. The approximately 10 percent re-
A
duction in mobile source 1977 emissions is due to the VMT reduction implied
by vehicle restraints.
Table S.F.2 lists the predicted annual emissions for NO for the
/\
entire grid network for each transportation control condition. Both total
emissions and mobile source emissions are given. The emissions from this
table ca>, be used for "rollback" calculations if desired.
3-55
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3.6 METROPOLITAN AREA ANALYSIS LOS ANGELES
3.6.1 Data Base And Methodology
3.6.1.1 Transportation Data
• Basic Data
The California Division of Highways, District 7 Office, provided
the basic information required to undertake the VMT and emission analysis
for the Los Angeles area. Specifically, the following data were provided
for 1967 and 1980:
1. Vehicle miles for zonal and intrazonal VMT grouped
according to Regional Analysis Zones (RAZ).
2. Intrazone trips and path values (in minutes for 1967
Study Zones).
3. Intrazone frequency distribution.
4. Set of 1967 zone maps showing RAZ boundaries.
5. Los Angeles Regional Transportation Study area road map
showing the location of 24-hour traffic counts.
6. Set of 24-hour traffic counts by hour. The location
of these counts are shown on the LARTS area road map.
7. Plots of 1967 and 1980 networks and network maps.
8. Cordon counts for downtown Los Angeles.
9. Population, housing, and employment data showing Southern
Calif. Assoc. of Govt. decennial figures for 1970 through 2C20.
10. Economic summary data for the LARTS area showing vehicle
trips, miles and minutes for 1967 and 1980.
11. Automobile ownership data for the Los Angeles Metropolitan
area.
12. Regional maps.
Vehicle miles were calculated for all regional analysis zones
(approximately 120), and the 20 regional analysis zones that had been
under consideration for exclusion were finally included as part of the
basic VMT measures provided by the California Highway Department.
Because the gravity model used to generate VMT did not include any
capacity constraints, some links were probably overloaded. Unfortunately,
no downward adjustment could be made for these overloaded links.
3-56
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The 1980 networks that were used were those designated as
"Alternative E-F." This alternative is considered by the Division of
Highways as the one most likely to be constructed. "Alternative E-F"
includes all of Interstate 105 and 210; Route 118 completed in Ventura
County; Route 7 extended from Long Beach to Route 210 in South Pasadena;
Route 2 to Route 101 completed in North Glendale, Beverly Hills; Route 1
completed in Long Beach; and several additions in San Bernardino and
Riverside Counties. There is community opposition to a number of the
proposed elements of the network and it is by no means certain that all
of "Alternative E-F" will be built as used for 1977 VMT analysis.
However, it represents the most conservative (and only) construction
assumptions available for analysis. Its limitations must, however, be
kept clearly in mind. Because of the lack of other factors, a logarithmic
interpolation was used for estimating between 1967 and 1980 in order to
arrive at the 1977 estimate VMT.
• Speed
In the basic data provided by the California Division of
Highways, the 1967 speeds were running speeds and the 1980 speeds were
policy speeds as used by the Highway Division for its forecasts for four
classes of road: urban, freeway, rural, and local streets. From this
base, the Los Angeles printout for 1967 and 1980 VMT provided for both
peak and off-peak speeds. Based on these speeds and the calculation of
the share of the eight-hour peak VMT out of the 24-hour total, the
following rule was used in obtaining the speed factors for each RAZ:
Peak Hour Speed = Use as the maximum 1-hour speed
Off-Peak Speed Use as the average 24-hour speed
Midpoint between the Peak and Off-Peak = Use as the Maximum
eight-hour speed
• Estimate of One- and Eight-Hour Maximum VMT
Calculation of the required time distributions of VMT was
based on 24-hour traffic counts for selected counting stations representing
traffic volumes along major corridors in the Los Angeles area. Traffic
data for two directions on 18 counting stations were used for the
3-57
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analysis. Major emphasis was given to counting stations involving major
flows into the central portions of Los Angeles. All counting stations
for which data were available and within the 20 square mile radius were
included in the analysis, and selected stations for major traffic points
throughout the area were also included.
Based on these traffic counts for 24 hours, the following
factors were used in the analysis:
One-hour Peak as a Percent of the 24-hour Total 7.4 percent
Eight-hour Peak as a Percent of the 24-hour Total = 48.0
percent
• Processing Los Angeles VMT Printout Data Reducing Coverage
Because of the very large area included within the Los Angeles
Regional Transportation Study (LARTS) and the relatively sparse popula-
tion, employment and trip densities for many of the Regional Analysis
Zones (RAZ), it seemed advisable to eliminate as many of the RAZ's as
possible in order to reduce the number of square mile grids used for
analysis. Many of the RAZ's had so few trips (e.g., VMT) and were so
large in area that their elimination reduced VMT by very small amounts
while cutting the number of grids needed sharply. Furthermore, in view
of the fact that emphasis was on the CBD and the peak hour work trips,
the eliminated zones assumed even less significance to the analysis.
Using the latter as a guide, the RAZ's eliminated (for information
purposes SCAG-Southern California Association of Governments-number are
shown) are shown below:
SCAG# RAZ# SCAG# RAZ# SCAG# RAZ# SCAG#_RAZ#
1
5
6
7
10
0100
0500
0600
0700
1000
11
15
30
30
41
1100
1500
3010
3020
4100
43
44
45
47
47
4300
4400
4500
4710
4720
48
48
49
49
50
4810
4820
4910
4920
5000
3-58
-------
• Calculation of 1967 and 1980 LARTS VMT
Calculation of VMT for each RAZ involved three basic steps:
(1) Calculation of interzonal VMT for each of the RAZ's, (2) calculation
of intrazonal VMT using intrazonal trip data provided for each RAZ and a
factor for counting trip data into VMT also provided by the Division of
Highways, and (3) combining inter- and intra-zonal VMT to obtain total
VMT for the analysis.
3.6.1.2 Meteorological Data
Annual average wind speeds and directions were obtained from
National Climatological data charts. It should be noted that these aver-
ages represent typical cases for the area and are applied only to give
representative samples of the possible dispersion patterns for the area.
The Los Angeles Basin is an area as described in Section 2.3 where physical
and meteorological conditions are not adequately represented by the gener-
alized model. Therefore, the "worst case" maximum concentrations predicted
are not expected to agree closely with maximum ambient values.
3.6.1.3 Stationary Sources
The 1967 stationary sources were estimated as percentages of the
total emissions for the area using data supplied by EPA. These percentages
were used to calculate the total emissions on a per-grid basis by applying
the percentage to the mobile emissions calculated for each grid. The
1977 stationary source emissions were estimated from the state implemen-
tation plan.
3.6.2 Summary of Results
The following discussion presents the impact of the transportation
controls on each of the three pollutants considered. Figure L.A.I shows
the analysis area.
3.6.2.1 Carbon Monoxide
Table L.A.I summarizes the maximum emissions and maximum concen-
trations predicted for carbon monoxide for each of the applied control
3-59
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Figure L.A.I.
Total Area = 900 sq mi
Individual Grid Area - 1 mi
Los Angeles Grid Network
3-60
-------
CARBON MONOXIDE
1967
1977
Strategy 1
Strategy 2
Strategy 3
MAXIMUM EMISSIONS
(tons/year)
Total
22029 (612)*
5977 (612)
5414 (612)
5729 (612)
4949 (612)
Mobile
21675 (612)
5623 (612)
5060 (612)
5375 (612)
4595 (612)
MAXIMUM CONCENTRATIONS
(mg/m3) (Worst Case)
8 Hr
36 1 (571>
36J (601)
7.3 (601)
6.6 (601)
6.9 (601)
5.9 (601)
1 Hr
51 6 (571)
51 '6 (601)
24.0 (612)
21.7 (612)
22.4 (612)
19.2 (612)
NITROGEN OXIDES
1967
1977
Strategy 3
MAXIMUM EMISSIONS
(tons/year)
Total
?183 (571>
2183 (601)
1070 (601)
916 (612)
Mobile
1570 <571)
1570 (601)
465 (612)
442 (612)
MAXIMUM CONCENTRATIONS
(ug/m3) (Worst Case)
8 Hr
3100 <571)
3100 (601)
1400 (601)
1300 (601)
1 Hr
3700 <571)
3700 (601)
2400 (soil
23nn <571)
2300 (612)
*The numbers which appear in parentheses represent the grid numbers in which
the maximum occurs. See Figures L.A.2, L.A.3, and L.A.4 for location of
these maxima for CO, HC, and NOX> respectively.
Table L.A.I. Predicted? Maximum Emissions and Concentrations
3-61
-------
strategies and the uncontrolled cases. The maximum concentrations are
centered in the central business district and near the intersection of
major freeway systems as shown in Figure L.A.2.
Stationary sources are treated as background emissions as described
in Section 3.6.1.3. The procedure does not have a critical effect on CO
emissions or concentration patterns in Los Angeles because stationary
sources represent an insignificant percentage of total CO emissions in this
area.
The 1977 predictions given in Table L.A.I show the major impact
of emission control devices on the maximum eight-hour and peak-hour con-
centrations. The 1967 maximum emissions are reduced by 74 percent. The
reduction appears to be sufficient to reduce concentration maximums to
below standard levels; however, under severe stagnation conditions fre-
quently experienced in this area, the eight-hour "worst case" prediction
may be exceeded (see Section 2.3).
An inspection and maintenance program (Strategy 1) would reduce
the maximum predicted 1977 emissions by approximately 10 percent. This
would not have a marked influence on predicted concentrations; however,
it would ensure that the automotive emissions did not increase above the
level assumed in the uncontrolled case, i.e., that automotive control
devices were operating at assumed efficiencies.
Strategy 2 (Traffic Flow Controls) assumes an average increase in
vehicle speeds. This strategy would reduce 1977 uncontrolled mobile emis-
sions by approximately five percent. The benefit of this speed increase
may be quickly deteriorated by induced traffic volume unless vehicle
restraints are applied.
The reduction in mobile source emissions produced by the combined
strategies (Strategy 3) is greater than the sum of reductions from the
individual strategies because of the added emission reduction achieved by
a small percentage VMT reduction. This VMT reduction is a result of
3-62
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Figure L.A.2. Maximum CO Concentration Location 1 for
1967 and Location 2 for 1977, Strategy 1,
Strategy 2, and Strategy 3
3-63
-------
vehicle restraints applied to maintain the average vehicle speed increase
attained through traffic flow controls. The combined emission reduction
would be approximately 18 percent of the 1977 uncontrolled vehicle emis-
sions and may be sufficient to maintain maximum concentrations at below
standard levels for the "worst case" defined by the model.
Table L.A.3 summarizes the annual emission totals for each pollu-
tant for the entire grid network for each transportation control condition.
These values can be used for "rollback" calculations if desired.
3.6.2.2 Hydrocarbons
Table L.A.2 includes the maximum emissions and concentrations
predicted for each transportation condition for hydrocarbons. Figure L.A.3
shows the location of the maximum concentrations predicted. It should be
recalled that stationary sources are treated as a percentage of the total
emissions and vary directly with mobile source emissions (see Section
3.6.1.3). Therefore, although the absolute value of the predicted concen-
trations is greatly influenced by the stationary sources which contribute
approximately 34 percent of the hydrocarbon emissions in the area, the
distribution patterns are representative of mobile sources only. It should
also be noted that the impact of the stationary source emissions on pre-
dicted concentration values increases markedly as automotive emission control
is increased. In consideration of these data base features and the distor-
tion of stationary source diffusion characteristics inherent in the ground-
level, area source diffusion model, it would be more appropriate to consider
the relative reduction in mobile source emissions rather than resultant
concentrations for the purpose of analyzing the impact of transportation
controls on hydrocarbons.
The 1977 uncontrolled mobile source emissions show a reduction in
maximum emissions of approximately 80 percent over 1967 emissions for
hydrocarbons. An Inspection and Maintenance program as suggested by
Strategy 1 would maintain the efficiency of the control devices and give
an additional 12 percent reduction in mobile emissions.
3-64
-------
cn
en
HYDROCARBONS
1967
1977
Strategy 1
Strategy 2
Strategy 3
MAXIMUM EMISSIONS
(tons/year)
Total
5029 I571!1
bu^y (601)
2397 (612)
2316 (612)
2375 (612)
2262 (612)
Mobile
3304 (571)
^w (601)
674 (612)
593 (612)
652 (612)
539 (612)
MAXIMUM CONCENTRATIONS
(yg/m3) (Worst Case)
8 Hr
7600 !571>
7600 (601)
2700 (601)
2700 (601)
2700 (601)
2600 (601
1 Hr
9800 !gg]!
4300 (65o]j
4000 Sg7]|
4100 (601)
3900 (601)
3 Hr2
15000 [6571j
5400 (601)
5400 (601)
5400 (601)
5200 (601)
3 Hr3
17000 [loii
7400 {Slj
6900 (6ol)
7000 (601)
6700 (601)
numbers which appear in parentheses represent the grid numbers in which the maximum occurs.
Figures L.A.2, L.A.3, and L.A.4 for location of these maxima for CO', HC, and NO , respectively.
J\
2Based on conversion of predicted concentration for eight-hour average by Larsen's method.
3Based on conversion of predicted concentration for one-hour average by Larsen's method.
See
Table L.A.2. Predicted Maximum Emissions and Concentrations
-------
I
CM
TRANSPORTATION
CONDITIONS
1967
1977
Strategy 1
Strategy 2
Strategy 3
CARBON MONOXIDE
Total
2703259
782050
708118
739949
638886
Mobile
2659900
738734
664802
696632
595570
HYDROCARBONS
Total
669174
264478
252904
259602
243449
Mobile
439632
96453
84879
91577
75424
NITROGEN OXIDES
Total
287097
160512
NA
NA
153176
Mobile
206423
85598
NA
NA
78262
Table L.A. 3. Annual Emissions (tons/year) for the Area Shown in Figure L.A. 1.
-------
Figure L.A.3. Maximum HC Concentration Location for
All Transportation Control Conditions
Listed in Table L.A.I.
3-67
-------
Strategy 2 (Traffic Flow Controls) would reduce 1977 uncontrolled
mobile source emissions by approximately four percent. The implied speed
increase has very little effect in the Los Angeles areas because the
current average vehicle speeds are relatively high. This strategy would
probably have a negligible effect on area-wide concentration values unless
extensive vehicle restraints are applied. The only apparent advantage to
the application of this strategy would be the reduction of short-term
concentration values in local areas of congestion.
The combined traffic flow control and vehicle restraints suggested
by Strategy 3 would reduce 1977 uncontrolled mobile source emission by
approximately eight percent. The major portion of this reduction is
attributable to a five percent reduction in VMT implied by vehicle
restraints.
Table L.A.3 summarizes the predicted total annual emissions for
the entire 900 square mile grid network. The hydrocarbon emissions given
in this table can be used for "rollback" calculations if desired.
3.6.2.3 Oxides of Nitrogen
Table L.A.I summarizes the maximum emissions and concentrations
for NOX in the grid area. Figure L.A.4 shows the location of the maximum
concentrations. It can be seen from the table that predicted concentra-
tion values are significantly effected by stationary source contributions.
Therefore, the relative reduction in mobile source emissions is considered
rather than resultant concentrations for the purpose of analyzing the impact
of transportation controls.
The 1977 uncontrolled mobile source emissions show approximately
a 70 percent reduction over 1967 mobile source emissions.
Strategy 3 (combined strategies) is the only transportation control
strategy with a direct impact on NO emissions. The approximately five
A
percent reduction in maximum mobile source 1977 emissions is a result of a
small percentage VMT reduction Inherent in vehicle restraints.
3-68
-------
Figure L.A.4.
Maximum NOx Concentration Location for
All Transportation Control Conditions
Listed in Table L.A.I.
3-69
-------
Table L.A.3 summarizes the annual emissions for the entire grid
network. The emission totals in this table can be used for "rollback"
calculations if desired.
3-70
-------
4.0 METROPOLITAN AREA ANALYSIS - WASHINGTON, D.C.
(CASE STUDY)
4.1 DATA BASE AND METHODOLOGY
4.1.1 Transportation Data
• Basic Data
Information relating to VMT and speed were made available in
the form of computer printouts from the regional transportation planning
agency: The Metropolitan Washington Council of Governments (COG).
Specifically, 1968 base year values for peak- and 24-hour VMT were
provided. Speed data were not available in usable form, and separate
speed estimates were prepared for each zone in the eight rings comprising
the Washington Metropolitan Area.
Of considerable importance is the fact that the VMT data pro-
vided for the 24-hour period does not include the District city streets.
These streets (mostly collectors and distributors) could account for a
significant portion of the VMT, and one estimate indicated that close to
40 percent of the 24-hour VMT might be on local city streets not included
in the VMT data provided. However, time and budget constraints did not
permit estimation of the distribution of these VMT; therefore, calculations
were based on the VMT provided by the COG printouts. Clearly, the emission
levels are understated because of the missing local street VMT.
• Speed Estimates
Because zonal speed information was not available in a usable
form, estimates of average zonal speed were made. These estimates were
based on the available data which included (1) the speed data used in
coding the links in the traffic assignment model, (2) speed data based on
a network transit study, (3) raw data on speed runs using a free floating
vehicle method, and (4) maps showing isochrones of travel time for 1959,
1966, 1969 and 1970 prepared. Using the speed maps, speed assignments
were made on a zonal basis.
4-1
-------
• Projections
Because no projected VMT was available, simple projections to
1977 were made using COG employment projections. Specifically, 24-hour
total VMT were summed for each of 146 small planning areas covering the
metropolitan area. These figures represent average weekday VMT for 1968.
The 24-hour VMT were multiplied by .482, representing the average percent
VMT for an eight-hour maximum, to find the average weekday eight-hour
maximum VMT for each of the small planning areas. The eight-hour maximum
VMT for 1968 were projected to 1976 using the COG small planning area
employment projections. The eight-year change was augmented linearly to
give a projection for 1977.
For the peak one-hour projections, peak-hour VMT were summed
for each of 146 small planning areas covering the metropolitan area. These
figures represent average weekday peak-hour VMT for 1968. These peak-hour
VMT for 1968 were projected to 1976, again using COG small planning area
employment projections; and the eight-year change was again augmented
linearly to give a projection for 1977.
It should be noted that this procedure results in a constant
ratio of peak-hour VMT to maximum eight-hour VMT for each small planning
area. There is, however, an implicit increase in vehicle miles traveled
per capita, and even per employed person, because most of the increase
takes place in the outlying rings. These outlying rings involve a much
higher VMT per person than average for the District.
t Estimates of Eight- and Peak-Hour VMT
"Vehicle Volume Summaries" for the second quarter, 1971, were
obtained from the District of Columbia Department of Highways and Traffic
for 96 stations in Washington, D. C. Each of these summaries includes
weekday average counts (both inbound and outbound) for half-hour periods
throughout the day.
Twenty-one major points were selected for calculations. These
cover the Washington, D. C., area in grid-like fashion and include most
4-2
-------
bridges. Vehicle counts for each of the 24 eight-hour periods (beginning
on the hour) were calculated. In 11 of the 21 cases, the traffic count
was highest in the period 11 a.m. to 7 p.m. In eight cases, the count was
highest in the period 12 noon to 8 p.m. In one case, the peak period
began at 10 a.m., and in one case at 8 a.m.
The ratio of peak eight-hour traffic ranged from 46.2 percent
to 52.0 percent with a mean of 48.2 percent of 24-hour vehicle counts.
There is no systematic variation related to distance from the urban core.
If the period 11 a.m. to 7 p.m. is selected for all points, the vehicle
count is approximately 48 percent of the 24-hour count. Other eight-hour
periods are a lower proportion of the total.
4.1.2 Meteorological Data
Wind roses for Washington, D. C., were used to determine the sea-
sonal average wind directions and speeds. It should be noted that these
averages may not truly represent the required maximum eight-hour and
peak-hour traffic averaging periods. A detailed analysis of the hourly
wind data would be required to obtain this accuracy. It should, therefore,
be understood that the chosen wind speeds and directions represent typical
cases for the area and are applied only to given representative samples
of the possible dispersion patterns for the area.
4.1.3 Stationary Sources
Detailed point source data for Washington, D. C., were available
and were included in order to give a more realistic projection of concen-
tration values.
t
Projections for stationary source emissions for the District show
a negligible change expected by 1977.
4-3
-------
4.2 SUMMARY OF RESULTS
The selected diffusion model was applied to the Washington, D. C.,
metropolitan area. Four meteorological conditions were considered as
follows: (1) Summer wind at 5.5 meters/second, (2) winter wind at 6.6
meters/second, (3) nominal (typical) wind at 5.0 meters/second, (4) "worst
case"wind at 2.5 meters/second. Three transportation conditions were
considered as follows: (1) Current conditions - as close to present
conditions as transportation data allow, in this case 1968; (2) projected
transportation conditions for 1977 assuming no additional transportation
controls (beyond internal automotive emission controls); and (3) pro-
jected conditions for 1977 with estimations of the effects of various
transportation controls. Figure D.C. 1 shows the grid system for Wash-
ington, D. C., utilized in the model. Isopleths D.C.I D.C.33 present
isopleths for CO, NO , and HC for the meteorological conditions and trans-
X
portation control conditions listed above.
Both mobile and stationary sources are included as pollutant sources.
Mobile sources emit about 99 percent of CO, 88 percent of HC, and 31 percent of
NOX in D.C. area. It is clear that transportation controls will have the greatest
impact on CO control and little effect on NOX control. Also, the assump-
tion of area sources in the model is more nearly true for CO emissions
than for HC and NOX which have significant contribution from point sources.
Consideration of large point sources such as electric power generating
plants in a particular grid reduces the applicability of the "relatively
smooth" assumption in the model. The resulting pollutant concentrations
will show a high value in the grid containing the large source and low
values in the surrounding grids as if the large source did not exist.
This effect should be considered when reviewing the isopleths for HC and
NOX.
The impact of various transportation controls on air quality was
estimated. The particular controls to be evaluated were selected as
described in Section 2.4 of this report. Although
4-4
-------
Figure U.C.I. Grid network
Total Area = 1024 knr
t
Individual Grid Area = 1 km'
4-5
-------
many potential controls were considered, only three were selected for
impact calculations due to project limitations. These were:
Strategy 1 - Inspection and Maintenance. This strategy was applied
as a reduction in CO emissions.
Strategy 1A - A 25% reduction in CO emissions was used for
illustrative purposes.
A 10% reduction in CO emissions and a 12%
Strategy IB
HC reduction was applied as the most likely
impact of this strategy.
Strategy 1C - A 5% reduction in CO emissions was applied for
illustrative purposes.
Strategy 2 Traffic Flow Control. Average speeds within each of
the speed rings in the original data were increased to indicate
the impact of this strategy.
Strategy 3 Combined Strategies. The impact of Strategy IB and
Strategy 2 were combined with a VMT reduction due to vehicle
restraints to produce the most optimistic pattern of emission
reductions.
The following represents a discussion of the impact of these control
strategies on each of the three pollutants considered.
4.2.1 Carbon Monoxide
Table D.C.I is a summary of the maximum emissions and maximum
concentrations predicted for carbon monoxide for each of the applied
control strategies and the uncontrolled cases. The maximum concentrations
predicted are given for the "worst case" which is defined by a wind speed
of 2.5 rn/sec. The maximum concentration for all cases occurs near the
center of D. C. in the immediate vicinity of the area of greatest traffic
dens i ty.
There were no major stationary sources of CO in the immediate vicinity
of this maximum concentration area as shown by the mobile and total
4-6
-------
CARBON MONOXIDE
1968
1977
Strategy 1A
Strategy IB
Strategy 1C
Strategy 2
Strategy 3
MAXIMUM EMISSIONS MAXIMUM CONCENTRATIONS
(tons/year) (mg/m3) (Worst Case)
Total
12589 (433)*
4513 (433)
3384 (433)
4061 (433)
4287 (433)
4412 (433)
3687 (433)
Mobile
12589 (433)
4513 (433)
3384 (433)
4061 (433)
4287 (433)
4412 (433)
3687 (433)
8 Hr
28.4 (433)
10.6 (433)
7.9 (433)
9.5 (433)
10.1 (433)
10.3 (433)
8.4 (433)
1 Hr
59.1 (433)
22.1 (433)
16.6 (433)
19.9 (433)
21.0 (433)
21.2 (433)
17.2 (433)
NITROGEN OXIDES
1968
1977
Strategy 3
MAXIMUM EMISSIONS MAXIMUM CONCENTRATIONS
(tons/year) (yg/m3)( Worst Case)
Total
6022 (307)
6005 (307)
6001 (307)
Mobile
439
271
241
433)
433)
464)
[464)
8 Hr
7200 (307)
7200 (307)
7200 (307)
1 Hr
7500 (307)
7300 (307)
7300 (307)
*The numbers which appear in parentheses represent the grid numbers in which the
maximum occurs. See Figures D.C.2, D.C.3, and D.C.4 for the location of these
maxima for CO, HC, and NOX, respectively.
»,
Table D.C.I. Predicted Maximum Emissions and Concentrations
4-7
-------
emissions; therefore, the maximum concentrations are a result of mobile
source emissions only.
The 1977 predictions show the effect of emission control devices on
the maximum eight-hour and peak-hour concentrations. The 1968 maximum
concentrations would be reduced by nearly two-thirds without the applica-
tion of any further controls.
Strategy 1 illustrates the possible additional reduction in CO
emissions which can be accomplished by implementing an inspection and
maintenance program for the D. C. region. This strategy would allow a
reduction in CO emissions ranging from 5 percent to 25 percent, with
10 percent being the most likely reduction. A 10 percent reduction in
CO emissions would bring the eight-hour concentration maximum slightly
below the Federal standard of 10 mg/m .
The traffic flow control strategy (Strategy 2) would, in effect,
increase the traffic speeds in the downtown area. This would, in turn,
decrease the emissions and result in an ^5 percent decrease in the eight-
hour maximum concentration over and above the predicted 1977 concentra-
tions. Without additional traffic controls, this 5 percent decrease
would probably disappear within one year due to induced traffic volume
increases.
Strategy 3 shows the effect of combining Inspection and Maintenance,
(10 percent CO reduction), traffic flow control, and vehicle restraints
(10 percent reduction in VMT). The prediction assumes full benefit of all
strategies would be achieved in 1977. The resulting maximum eight-hour
concentration is approximately a 20 percent improvement over the predicted
uncontrolled 1977 concentrations. This would bring the eight-hour maximum
concentration safely below the Federal standard.
The general location of the maximum concentrations for each of the
transportation conditions is shown for Carbon Monoxide in Figure D.C.-2.
Table D.C.-3 summarizes the annual emission totals for the entire grid
4-8
-------
Figure D.C.2. Maximum CO Concentration Locations' for All Transportation
Conditions Given in Table D.C.I
4-9
-------
o
TRANSPORTATION
CONDITIONS
1968
1977 (uncontrolled)
Strategy 1A (25%)
Strategy IB (10%)
Strategy 1C ( 5%)
Strategy 2
Strategy 3
CARBON MONOXIDE
Total
857422
328065
247189
295715
31188
3031 51
263092
Mobile
852838
323481
242606
291132
307304
298567
258508
HYDROCARBONS
Total
152577
54457
NA
49436
NA
51944
43806
Mobile
139957
41844
NA
36823
NA
39331
31193
NITROGEN OXIDES
Total
73922
57639
NA
NA
NA
NA
53029
Mobile
57029
40900
NA
NA
NA
NA
36281
Table D.C.2. Annual Emissions (tons/year) for the Area Shown in Figure D.C. 1.
-------
area for each transportation control condition. Table D.C.3 values can
be used for "rollback" calculations for the area.
4.2.2 Hydrocarbons
Table D.C.2 summarizes the maximum emissions and maximum concentrations
for hydrocarbons in the grid area. Figure D.C.3 shows the location of these
maxima. Note that peak-hour concentrations are given although federal
standards are suggested only for a three-hour (6 - 9 a.m.) average.
Transportation data given did not allow estimation of concentrations for
this specific time period; therefore, the Larsen model was used to estimate
the three-hour averages from the predicted eight-hour and one-hour concen-
trations as shown in Table D.C.2.
It can be seen by the difference in total and mobile source emissions,
shown in Table D.C.2, that the maximum concentrations values are greatly
affected by stationary sources. For the purpose of analyzing the effect
of transportation controls, it is more appropriate to consider the relative
reduction in mobile source emissions rather than the reduction in predicted
maximum concentrations. The 1977 uncontrolled mobile emissions show a
reduction of approximately 70 percent over base year mobile emissions.
In the vicinity of the CAMP monitoring station, this reduction would be
sufficient to meet the standards; however, near major stationary sources
(i.e., National Airport) stationary source and aircraft emissions account
for the majority of emissions and the total predicted concentrations are
distorted. Therefore, it is difficult to predict the actual concentration
reduction achieved.
Inspection and maintenance would reduce mobile source emissions by
12 percent. Traffic flow control (Strategy 2) would have very little
effect by itself on mobile sources; however, by combining traffic flow
control with vehicle restraints as given by Strategy 3, an additional
12 percent reduction in mobile emissions could be achieved.
4-11
-------
ro
HYDROCARBONS
1968
1977
Strategy 1
Strategy 2
Strategy 3
MAXIMUM EMISSIONS
(tons/year)
Total
2019 (272)1
1862 (272)
1803 (272)
1859 (272)
1795 (272)
Mobile
1773 (433)
490 (433)
431 (433)
482 (433)
369 (433)
MAXIMUM CONCENTRATIONS
(lag/m3) (Worst Case)
8 Hr
4100 (433)
2900 (241)
2700 (241)
2800 (241)
2700 (241)
1 Hr
8300 (433)
3100 (241)
3000 (241)
3100 (241)
2900 (241)
3 Hr2
5500 (433)
3900 (241)
3700 (241)
3800 (241)
3700 (241)
3 Hr3
6700 (433)
2500 (241)
2400 (241)
2500 (241)
2400 (241)
LThe numbers which appear in parentheses represent the grid numbers in which the maximum occurs. See
Figures D.C.2, D.C.3, and D.C.4 for the location of these maxima for CO, HC, and NO , respectively.
J\
2Based on conversion of predicted concentration for eight-hour average by Larsen's method.
3Based on conversion of predicted concentration for one-hour average by Larsen's method.
Table D.C.3. Predicted Maximum Emissions and Concentrations
-------
/ CITYOF\
ALLS CHURC
HV
INTERSTATE 495
ff
m
WASHINGTON. D.C.
c:
\>
CITY OF ALEXANDRIA
Figure D.C.3.
Maximum HC Concentration Location 1 for 1968 Uncontrolled
Location 2 for All Other Transportation Conditions Given
in Table b.C.l.
4-13
-------
The distribution of resultant hydrocarbon concentrations is given
in the isopleth patterns in Appendix A. Obviously, these patterns are
grossly affected by major stationary sources and are not representative
of the impact of mobile sources or transportation controls.
Table D.C.3 lists the predicted annual emissions for the entire
grid network for each transportation control condition. Both total
emissions and mobile source emissions are given. The annual mobile
source emissions in this table could be used in conjunction with a
detailed inventory of other sources to obtain total emission estimates
for "rollback" calculations.
4.2.3 Oxides of Nitrogen
Table D.C.I summarizes the maximum concentrations and emissions for
NO in the grid area. Figure D.C.4 shows the location of the areas of
A
predicted maximum concentrations for each transportation control condition.
It can be seen from the table that the predicted maximum concentra-
tions are a result of emissions from large stationary sources included in
the data base. Maximum concentrations resulting from the maximum mobile
source emissions given in the table would be approximately 60 percent
less or about 3.0 mg/m for the eight-hour maximum concentration. For
the purpose of analyzing the effect of transportation controls, it may be
more appropriate to consider the relative reduction in mobile source
emissions rather than the relative reduction in predicted maximum concen-
trations which are so grossly affected by stationary source emissions.
4-14
-------
INTERSTATE 496
/
C
CITV OF
WASHINGTON , D.C.
CAMP
£'.
(,
t I
\»
CITY OF ALEXANDRIA
Figure D.C.4. Maximum NO Concentration Locations for All Transportation
Conditions Given in Table D.C.I.
4-15
-------
The 1977 uncontrolled mobile emissions show a maximum reduction of
approximately 40 percent over base year mobile emissions. This reduction
is due solely to direct automotive emission controls. Whether this
reduction alone would be sufficient to bring actual air quality within
the federal guidelines would be dependent on the extent to which the
standards are exceeded and the 1977 contribution from stationary
source emissions.
Strategy 3 (combined emission and traffic control strategies) is
the only transportation control strategy with a direct impact on NOX
emissions. The approximately 10 percent additional reduction in mobile
emissions is a result of reduced VMT due to vehicle restraints.
The distribution of predicted NO concentrations is given in the
A
isopleth patterns for NOX in Section 4.4. Obviously, these patterns
are grossly affected by major stationary sources and are not representa-
tive of the impact of mobile sources or transportation controls.
Table D.C.Slists the predicted annual emissions for the entire
grid network for each transportation control condition. Both total
emissions and mobile source emissions are given. The annual mobile
source emissions in this table could be used in conjunction with a
detailed inventory of other NOX sources to obtain total emission
estimates for "rollback" calculations.
4-16
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4.3 COMPARISON OF CALCULATED CONCENTRATIONS WITH AMBIENT MEASUREMENTS
It is of interest to compare the calculated concentrations value witn
the available measurements of air quality.^ The available data for
Washington, D.C., which are those from the CAMP station in grid numuer
403 of Figure D.C.I, were obtained from the D.C. Bureau of Air and Water
Quality Control. The CAMP station data show worst case one-hour and
eight-hour averages for CO of 50 and 32 mg/m3 and nominal values in the
ranges of 22 to 40 and 10 to 12 mg/m3. The calculated values agree quite
closely with those as shown in Table D.C.4.
CAMP station data for non-methane type hydrocarbons are given in
Table D.C.4. The basic modeling assumptions and variables as well as
ambient measurement methods should be carefully reconsidered before
comparing the calculated values with ambient values. As explained in
the preceding discussion of methodology, the area source assumption
is more valid for CO than for HC or NO . Grids containing large stationary
A
sources create small anomalous regions in the generally smooth isopleth
pattern. This distortion would be more prominent in the HC and NO isopleths
A
because of the large percentage of their emissions due to stationary sources.
The HC and NOY are chemically and photochemically reactive species
A
and the products of these reactions are dependent on many variables,
including radiation input and time. These variables are not explained
by the Gifford-Hanna model and, in fact, can only be explained oy complex
chemical reaction models requiring data input which are not readily
available for most cities.
^'Comparison of ambient data with predicted data required that sufficient
data for each pollutant be available for the specific time period required
by the model, i.e., the maximum eight-hour traffic period and the peak
traffic hour. Most major cities do maintain records of ambient concen-
trations for each of the three pollutants in some form; however, the
data are rarely available for the time periods required. Comparison
of predicted values for Washington, D.C., with ambient data was made
possible through discussions with D.C. air quality control personnel
intimately familiar with the data, who reviewed the available original
recorded data charts or applied their familiarity with the data to
obtain estimates of the concentration averages most representative of
the time period desired.
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CARBON MONOXIDE (CO)
(mg/m3)
CAMP
Predicted
Standard
Eight
Nominal
10-12
8-12
1
Hour
I'laximuii:
32
24
0
One
Nominal
22-40
18-24
Hour
Maximum
50
bl
40
HYDROCARBONS (HC)
(mg/rn3)
CAMP
Predicted
Standard
Total
1.3 - 2.0
(maximum)
Non-Methane
.33(6-9a.m.)
(maximum)
5.7
(3 hr. avg.)
.16(6-9a.m.)
NITROGEN OXIJES (NO )
(mg/m3) x
CAMP
Predicted
(NOX as N02)
Standard
N02
.12(8-hr. max.)
.T(8-hr. annual
mean)
NOX
.4-.8(8-hr. est.
max.)
•9(8-hr. max.)
Table D.C.4.
Washington, D.C., 1968 Ambient and Predicted
Pollutant Concentrations at the CAMP Station
4-18
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The impact of the unexplained variables and deviation from model
assumptions appears to be greatest for the hydrocarbons as seen in Table
D.C.3. The model utilizes emissions from mobile sources, which are pre-
dominantly non-methane hydrocarbons, to predict air quality. Since the
methane fraction of the total emissions is very small compared to the
non-methane emissions, removal of the methane fraction as input to the
model would not totally explain the gross disparity in calculated air
quality as compared to ambient measurements of non-methane hydrocarbons.
Comparison of predicted values with total hydrocarbons would have to
account for the large amount of ambient methane measured.
Ambient nitric oxide values and nitrogen dioxide values are given in
Table D.C.3. NO is not routinely monitored at the CAMP station. To
A
compare with the NOV ambient air quality as calculated by the model, an
A
estimate of nominal NO ambient air quality is also given in the table.
A
Air quality standards are written for NOg although the model emission
factors are given for NO as N09; the reason for this being that N0? is
A £ ^
a secondary pollutant and the model cannot explain atmospheric reactions.
Therefore, the model output should, perhaps, be compared to N0x values
rather than ambient N02 avalues. A rough estimate of NOX is obtained
from the nitric oxides and N02 ambient measurements at the CAMP station.
Comparison of these values still shows a large unexplained discrepancy.
Deviation from the area source assumption is most obvious in the NO
A
emissions (see Section 2.1); however, the extent or the impact of this
deviation on the calculated air quality values cannot be quantitatively
determined due to the complex nature of the other unexplained variables
such as atmospheric reactions.
4-19
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In summary, carbon monoxide is the gaseous pollutant which is most
compatible with the basic modeling assumptions; and the basic agreement
of ambient carbon monoxide measurements with the calculated a-tr quality
is felt to recommend the modeling approach selected for carbon monoxide
for D.C. The hydrocarbons and NCL deviate from some of the basic modeling
/\
assumptions or parameters. A quantitative analysis of these deviations
would require many more ambient samples which are not available for u.C.
and a detailed study of such factors as atmospheric reactions and ambient
monitoring methods which is beyond the scope of this current study. The
model does indicate the areas of worst case emissions for hydrocarbons and
NO and could be used as a "first guess" indicator of air quality in these
A
worst case areas; however, the numerical values of the predicted air
quality for these pollutants would not be reliable.
4-20
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APPENDIX A
WASHINGTON, D.C., ISOPLETHS*
The following isopleths are representative of the dispersion patterns
estimated for each pollutant for each of the given transportation conditions.
Isopleths D.C.I - D.C.8 represent the current carbon monoxide eight-
hour and peak-hour concentration patterns for each of four meteorological
conditions. Case 4 is the "worst case" as described in the text. Cases
1,2, and 3 are given to illustrate representative dispersion patterns.
Isopleths O.C.9 represents the one-hour "worst case" 1968 HC
dispersion pattern.
Isopleth D.C.10 represents the eight-hour "worst case" 1968 NOX
concentration pattern.
Isopleth D.C.ll - D.C.18 are the 1977 uncontrolled carbon monoxide
concentration patterns for those cases discussed above for 1968.
Isopleth D.C.I9 shows the one-hour "worst case" 1977 uncontrolled
HC concentration pattern.
Isopleth D.C.20 represents the eight-hour "worst case" 1977 uncontrolled
NUX concentration pattern.
Isopleths O.C.21 - D.C.26 show the effects of Strategy 1A, lb, and
1C on CO "worst case" concentrations.
Isopleths D.C.27 - D.C.29 represent Strategy 2 impact on CO and
HC "worst case" concentrations.
Isopleths D.C.30 - D.C.33 represent Strategy 3 impact on CO, HC,
and NO "worst case" concentrations.
*Isopleths for the other five metropolitan areas are available upon
request.
A-l
" ' ,«TJ. S. GOVERNMENT PRINTING OFFICE: 1978—746-767/4140
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