HDV 78-03
Technical Report
May 1978
Truck Driving Pattern and Use Survey Phase II
Final Report Part II Los Angeles
by
Leroy Higdon
May,197*f
NOTICE
Technical Reports do not necessarily represent final EPA decisions or
positions. They are intended to present technical analysis of issues
using data which are currently available. The purpose in the release of
such reports is to facilitate the exchange of technical information and
to inform the public of technical developments which may form the basis
for a final EPA decision, position or regulatory action.
Standards Development and Support Branch
Emission Control Technology Division
Office of Mobile Source Air Pollution Control
Office of Air and Waste Management
U.S. Environmental Protection Agency
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Forward
This report presents the data collection procedures used in Phase
II Part II of the CAPE-21, Truck Driving Pattern and Use Survey. It
covers only the data collection in Los Angeles, and describes collection
processes, equipment, personnel, sample plans and resultant data base.
No attempts are made to show conclusions as to the validity of the
data since this topic will be covered in a separate report to be released
at a later date.
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Table of Contents
Page
I. Introduction 1
II. Program Structure 4
III. Data Collection 26
IV. Summary 41
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List of Illustrations
Page
Figure 1 Sample Plan for Los Angeles 6
Figure 2 Georgraphic Sample Plan for Los Angeles ... 7
Figure 3 Registration Listings 9
Figure 4 Agreement 13
Figure 5 Block Diagram Data Acquisition System .... 18
Figure 6 Metro Data Acquisition System 19
Figure 7 Cassette Data Format 31
Figure 8 "Z" Test Output 32
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List of Tables
Table 1 Truck Acquisition Response Summary . . .
Table 2 Channel Assignment
Table 3 Test Equipment
Table 4 L.A. Trucks by Manufacturers
Table 5 Survey Data Base
Page
12
20
23
27
36
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-1-
I. Introduction
A. Background
Phase II Part II of the CAPE-21, Truck Driving Pattern and Use
Survey Is the continuation of: a two city survey consisting of New York
and Los Angeles.
This report deals only with Part II of the CAPE-21 program, and
covers the Los Angeles survey. The New York portion of the CAPE-21
program was conducted by Wilbur Smith and Associates and is covered in
a final report under the heading Phase II Part 1, Truck Driving Pattern
and Use Survey.
The selection of the two cities which make up the study was made
•jointly by a panel of representatives from the U.S. Environmental
Protection Agency (EPA) and the Coordinating Research Council (CRC). It
was based on the need for in-use heavy-duty truck data which, when
analyzed, would indicate typical truck operation in urban areas of the
United States.
To test a statistically acceptable number of vehicles in each urban
area in the United States for the purpose of determining how heavy-duty
vehicles are operated in normal service in each case, would have involved
the expenditure of vast amounts of manpower and finances and would have
taken a significant amount of time to complete. To overcome these
restrictions the CAPE-21 panel decided to select two cities which, when
combined statistically, represented the extremes in driving conditions
under which heavy-duty vehicles must operate.
The city of New York was chosen as representative of one extreme,
because it is an old city having a dense population in a relatively
small area, with narrow streets, limited numbers of expressways, and
numerous restrictions to automotive traffic movement in the form of
traffic control devices (stop lights and signs). The choice of Los
Angeles for the second city in the survey was made because it represents
just the opposite in extremes from New York. The rationale for the
selection of the two cities has been shown to be correct in an earlier
study conducted by Wilbur Smith and Associates of Columbia, South
Carolina. "'
The program objective was to collect engine and vehicle operational
data on a number of in-use heavy-duty trucks and buses, which would,
when analyzed, describe the way these vehicles are operated in regular
use by their owners. The data collected during the survey were intended
for use in the development of representative driving cycles for use. in
the testing of heavy-duty trucks and/or truck engines for compliance
with emission standards for the control of air pollution. From the
standpoint of emission testing for air quality control, the optimum in
any test cycle is reached when a single representative cycle can be used
which is representative of the way vehicles 'are operated in the control
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-2-
area of interest as a whole. To acheive this, the data base used in the
development of such a cycle must be representative of types of vehicles
predominantly used in areas which, when combined, represent the mean in
operational characteristics within the control area.
The CAPE-21 program, through careful design of its sample plan, is
a comprehensive study which will supply a data base that is statistic-
ally representative of heavy-duty truck operations in two localities.
When combined, this data base should reasonably represent the mean in
truck operation within the continental United States (the control area
of interest).
Phase II of the CAPE-21 program was conducted at a cost of just
over $250,000.00, excluding salaries, and an expenditure in manpower of
approximately 19,000 manhours. The Los Angeles survey was started in
January, 1975, and ran to May 1975. This report deals only with the
statistical sample plan, data collection operations, and instrumentation
used in the Los Angeles portion of the survey. Analysis of the data is
the subject of a separate project and will be reported on under separate
cover.
B. Conclusion
In-use data collection of the type sought in the CAPE-21 Truck
Driving Pattern and Use Survey is, in the authors opinion, bordering on
the upper extremes of state of the art for in-use motor vehicle data
collection. This condition is aggravated by the fact that the owners
involved in studies of this type are commercial operators depending on
these vehicles for profit revenue, a condition which strongly influences
every facet of the study. Participation by owners in in-use programs of
this type is greatly dependent on their awareness of problems of air
pollution, and the need for its control. In addition to this, the will-
ingness to participate extends only to the point where economics are not
a factor.
During the performance of the Los Angeles portion of the CAPE-21
study, every effort was made to inform the participants of the EPA's
need for conducting the study. Wherever possible the cost to owners
caused by the use of his vehicle in the survey was absorbed by EPA. The
results of this effort was an exceptional response on behalf of the
participants to aid in the success of the study.
With the completion of the Los Angeles Study, EPA has established
the formation of the most in-depth data base of in-use heavy-duty truck
operation ever assembled. The data describe, in explicit detail, the
operational characteristics of heavy-duty vehicles in actual use by the
operators. It is free from the outside influences or restrictions in-
herent in studies of this type when conducted entirely by skilled test
drivers and technicians. It depicts the movement of heavy-duty vehicles
in normal traffic over unpredicted routes in terms of road speed, and
the engine operational characteristics (RPM and power) from which this
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-3-
road speed is derived.
There can be little question as to the representativeness of the
data collected in the Los Angeles survey, in that every precaution was
taken to insure that the operators were not influenced in any way by the
survey team or the on board equipment, in the performance of their
normal duties.
The data base resulting from the CAPE-21 study is applicable to a
wide variety of investigative endeavors and should prove to be unparal-
leled in its usefulness for some time to come. It is not, however,
unlimited in its ability to answer or satisfy all possible questions
concerning the movement of heavy-duty vehicle operation in urban areas
of the United States, and when used should be considered with the same
degree of technical understanding afforded any other data base for its
original intent.
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II. Program Structure
A. Purpose
The CAPE-21 program was designed, and conducted to provide a data
base from which heavy-duty engine and chassis emission test cycles might
be developed which are representative of operation in the real world.
The data then have the ability to represent the mean operational charac-
teristics in the sample area from which it came.
B. Sample Plan
When planning to undertake a program like CAPE-21, one must first
decide on the area to be sampled and having done so identify the para-
meters to be sampled within the area. If the data to be collected are
to be used to represent the mean of the measured parameters within the
area, or if the area under consideration is assumed to be represented by
the data as being the norm or average characteristics as a function of
the area, then some method must be devised to measure the extremes which
can then be used to predict the means. When considering the extremes of
the sample area, it is necessary to consider the kind of data needed and
identify those parameters, within the sample area of interest, which
most greatly influence these parameters.
The sample area, in this case, is the United States, and the mean
can be derived if the extremes of the area are known. The total area of
the selected extremes can further be reduced in size when consideration
is given to the fact that, the EPA is primarily concerned with urban
areas in its efforts to control air quality. The test means (sample
size) can now be confined to vehicle operation within these extremes.
Because the study is concerned with traffic flow within the selected
portions of the extremes, the controlling factors in the types of data
that will result from the testing of vehicles within the recognized
confines of the sample area are directly relatable to the means in the
types of restrictions to traffic flow.
With the above considerations in mind, the city of New York was
considered as meeting one extreme because it is an old city having
narrow roadways, few limited access roads (freeways), a traffic control
system which consists of stop lights and stop signs requiring frequent
stop and start type operation, and external interference to traffic
flow, in the form of pedestrian crossing, in high volume at peak traffic
hours. Additionally, New York's major industries have been distinctly
located in specific sections of a city of relatively small area compared
to Los Angeles, the second city used in the survey. It was felt that
Los Angeles represents the opposite in every category mentioned above.
These two cities then were considered the area extremes for the CAPE-21
Truck Driving Pattern and Use Survey.
To satisfy the requirement for data which can be used for engine
and/or chassis cycle development, the parameters of major concern are 1)
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—5—
engine RPM, 2) engine horsepower and, 3) vehicle road speed. Sample
area parameters which most greatly effect these operational parameters
are, ]) topography, 2) degree of congestion which attributes restric-
tions to traffic flow, 3) traffic control systems, and 4) uncontrollable
and periodic interference to traffic flow (i.e., pedestrian movement).
In order to select the survey sample configuration, a Heavy-Duty
Vehicle Driving Pattern and Use Survey was conducted by Wilbur Smith and
Associates (WSA) ' under joint contract from EPA and CRC (Coordinating
Research Council) .. This survey (referred to as CAPE-21 Phase 1 Parts 1
and 2 for New York and Los Angeles respectively) was conducted in order
to acquire information pertaining to the composition, function, and
travel behavior of urban truck travel in the two cities. From Part 2 of
these data, a sample plan, which for economical reasons was restricted
to fifty (50) vehicles, was designed by WSA which, statistically, was
representative of the truck population in the Los Angeles Basin. (See
figure 1.)
After reviewing the Phase I Part 2 data and the resultant sample
plan submitted by WSA, several changes were made to better facilitate
the engineering and economical considerations of the data collection
program. The final sample plan used in the. Phase II Part 2 Los Angeles
survey (see figure 2) called for a total of fifty (50) vehicles to be
tested from five (5) geographical areas in the greater Los Angeles
basin. Each vehicle was required to have a gross vehicle weight (GVW)
of not less than ten (10) thousand pounds and would be tested for from
two (2) to five (5) days of normal in-service operation. A day of
operation was defined as any twenty-four (24)"hour calendar period
during which a vehicle Left its normal storage location, for one hour or
more duration, to perform a task or number of tasks, the length of which
was immaterial.
In addition to the fifty (50) vehicles originally scheduled to be
tested in the CAPE-21 program, five city busses were added to the study
in both New York and Los Angeles. These vehicles were to be. tested both
as inter-city as well as intra-city vehicles and were acquired from the
major transportation agencies in each location.
As an afterthought, and because the opportunity presented itself
favorably. Two trucks, one two axle tractor trailer, gas, and one two
axle single unit, gas, were instrumented and driven over the road be-
tween Los Angeles and San Francisco, California, and between Los Angeles,
California and Ann Arbor, Michigan. Similarly, a Trailways over-the-
road bus was tested between Los Angeles, California and Denver, Colorado.
Vehicles were divided into four (4) groups by axle configuration.
Two axle single unit (2A), three axle single unit (3A), two axle tractor
trailer (2TT) and three axle tractor trailer (3TT), busses were consid-
ered as a separate category. The sample was further divided into two
fuel classes, gasoline and diesel. In order to qualify as being repre-
sentative of operation in a given geographical area, a vehicle had to
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FIGURE 1
SAMPLE PLAN FOR LOS ANGELES
Strata
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.
6-10
6-10
10-15
10-15
15-20
15-20
6-10
6-10
10-15
10-15
15-20
15-20
20-25
20-25
6-10
6-10
10-15
10-15
15-20
15-20
20-25
20-25
25-30
25-30
30-35
30-35
+35
,000,
,000,
,000,
,000,
,000,
,000,
,000,
,000,
,000,
,000,
,000,
,000,
,000,
,000,
,000,
,000,
,000,
,000,
,000,
,000,
,000,
,000,
,000,
,000,
,000,
,000,
,000,
2
2
2
2
2
2
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
4
4
4
Axle,
Axle,
Axle,
Axle,
Axle,
Axle,
Axle,
Axle,
Axle,
Axle,
Axle,
Axle,
Axle,
Axle,
Axle,
Axle,
Axle,
Axle,
Axle,
Axle,
Axle,
Axle,
Axle,
Axle,
Axle,
Axle,
Axle,
Number
of Trucks
RC
BE
RC
BE
RC
BE
RC
BE
RC
BE
RC
BE
RC
BE
RC
BE
RC
BE
RC
BE
RC
BE
RC
BE
RC
BE
BE
TOTAL
10
8
2
1
0
0
0
1
1
3
1
1
0
0
0
0
0
0
1
1
2
4
1
8
1
3
1
50
Number
of Days
4 -
4
4
4
-
-
-
4
5
5
3
4
-
-
-
-
-
-
4
3
3
4
2
2
2
2
2
Truck Days
of Data
40
32
8
4
-
-
-
4
5
15
3
4
-
-
-
-
-
-
4
3
6
16
2
16
2
6
2
172
RC - Regular Commercial; BE - California Board of Equalization
Column 2 indicates the number of days truck is to be tested.
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FIGURE 2
GEOGRAPHIC SAMPLING PLAT; FOR
LOS ANGELES COUNTY
(CAPE-21)
Truck
Type
2A
3A
2TT
3TT
All
Areas
Gas Diesel
No.
No.
No.
No.
No.
No.
No.
No.
Trucks
Truck Days
Trucks
Truck Days
Trucks
Truck Days
Trucks
Trucks Days
20
80
3
12
5
16
2
8
3
8
4
20
5
10
8
18
Los
Angeles
Gas Diesel
8
32
1
4
2
4
1
4
1
4
1
5
2
4
3
6
Inglewood
Gas Diesel
3
12
1
4
1
4
0
0
0
0
0
0
1
2
1
3
Van Nuys/
Pasadena
Gas Diesel
3
12
0
0
1
4
0
0
0
0
1
5
0
0
1
3
Whittier/
Long Beach
Gas Diesel
4
16
0
0
1
4
1
4
1
2
1
5
2
4
2
4
Alhambra
Gas Diesel
2
8
1
4
0
0
0
0
1
2
1
5
0
0
1
2
Totals
23
88
7
32
10
26
10
26
oo
2TT
3TT
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-8-
have originated its daily operation in that area.
C. Vehicle Acquisition
Olson Laboratories Inc. (OLI) of Anaheim, California, under contract
to EPA to support the survey team, was supplied with listings of commer-
cially registered vehicles of the truck classes sought, by the Department
of Motor Vehicles for the state of California. The listing, a copy of
which is seen in figure 3, consisted of information regarding type of
truck, number of axles, weight, fuel type, and registered owner's name
and address. Using the listing OLI personnel contacted 480 owners by
phone in an attempt to locate the required vehicle in the required
operating locale. Two hundred twelve (212) owners meeting both truck
type and location requirements were contacted, of which sixty-two (62)
agreed to participate in the study. The difficulties experienced in
finding willing participants lie primarily in the information source
employed. As can be seen in figure 3, only the registered name and
address of owners are listed, this information does not indicate if the
vehicle is based at that location. During the survey it was found that,
in fact, some vehicles were not even based in the state of California.
Vehicles were finally obtained by starting with registered owners and
tracing the truck whereabouts by phone until a definite answer could be
obtained from the operator as to his willingness and ability to partici-
pate.
In addition to difficulties experienced in locating the required
vehicles, it was found that owners were reluctant to participate in the
program when it was learned that the study was being conducted by a
government agency. This problem stemmed from the fact that not only was
the truck to be instrumented, but that an on-board observer working for
the government would ride with the equipment. The thought was expressed
by owners that more was being monitored than vehicle operation. To
overcome this distrust, personal visits were made to prospective parti-
cipants to explain the intent of the survey and answer any questions,
this reduced declines to acceptable levels in California. Table 1 shows
the statistics for truck acquisition, and the resultant sample population.
Once the required vehicle was found the owner was required to sign
a written agreement authorizing the installation of the instrumentation,
and describing the legal obligations and limitations. The vehicle was
then delivered to one of two dynamometer facilities for installation and
calibration.
D. Vehicle Instrumentation Installation Scheduling
Once a participation agreement was secured, a vehicle was entered
into the scheduling process. This process consisted of obtaining a
signed agreement with the owner of the vehicle (figure 4), inspection of
the vehicle prior to instrumentation installation, and scheduling of the
vehicle for installation.
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FIGURE 3
DEPARTMENT OF MOTOR VEHICLES, STATE OF CALIFORNIA
REGISTRATION LISTINGS
Axle
Group
3
3
3
3
3
3
3
3
3
Weight
Group
15-20K
15-20K
15-20K
15-20K
15-20K
15-20K
15-20K
15-20K
15-20K
Year
65
73
69
71
69
69
66
64
67
Model
PTB
KEN
MCK
WST
KEN
KEN
WHI
KEN
PTB
Truck
Type
TAN
TRA
TRA
FLA
TRA
TAN
TRA
TRA
TRA
Cab
Loc.
U
U
U
U
U
U
U
U
U
Wheels
Fuel Tot.
D 9
D 9
D 9
D 9
D 9
D 9
D 9
D 9
D 9
Dr.
9
9
9
9
9
9
9
9
9
State
Weight
060
054
057
060
050
060
050
050
050
Name
Douglas Oil
Co.
Seven Flags
Co-Op
Dresser In-
dustries
Inc.
Sun Lumber
Co.
Selectruk,
Inc.
Southern
Tank Lines
Mr . Donald
W. Smith
Davidson C.
L. Truck-
ing, Inc.
Mr. Clifford
J. Turner
Address 1
816 West
5th St.
12420 Bloom-
field Av.
10960 Wil-
shire Bl.
3435 Wil-
shire Bl.
5030 Gif-
ford Av.
16613 Minn-
esota Av.
12004 S.
Louis Av.
420 Camino
De Encnt.
10919 S.
Van Ness Av.
Address 2
Los Angeles,
CA 90017
Sante Fe
Springs , CA
90670
Los Angeles,
CA 90024
Los Angeles,
CA 90010
Los Angeles,
CA 90058
Paramount ,
CA 90723
Whittier,
CA 90605
Redondo
Beach, CA
90277
Inglewood,
CA 90303
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FIGURE 3—Continued
Axle Weight Truck Cab Wheels State
Group Group Year Model Type LOG. Fuel Tot. Dr^ Weight Name Address 1 Address 2
3 15-20K 65 PTB DUM U D 9 9 057 Mr. David C. 10342 Rio El Monte,
Delacruz Hondo Pkwy. CA 91733
3 15-20K 64 KEN TRA U D 9 9 050 Wilennis, 1136 E. Los Angeles,
Inc. 58th Dr. CA 90001
3 15-20K 72 KEN TRA U D 9 9 054 Mr. Richard 3308 N. Burbank,
F. Millar Lamer St. CA 91504
3 15-20K 67 PTB TRA U D 9 9 054 Mr. Walter 15002 Kings- San Fernan-
C. Welty bury St. do, CA 91340
3 15-20K 64 KEN TRA U D 9 9 054 Mr. Anthony 247 N. San- La Puente,
G. Resales dalwood Av. CA 91744
3 15-20K 65 PTB TAN U D 9 9 057 Colbro Corp. 14011 S. Los Angeles,
Central Av. CA 90059
3 15-20K 68 KEN TRA U D 9 9 050 Berkeley In- 355 S. Los Angeles,
vestments, Flower St. CA 90017
Ltd.
3 15-20K 67 KEN TRA U D 9 9 054 Mr. James 2356 S. Los Angeles,
B. Hicks Sepulveda CA 90064
Bl.
3 15-20K 67 WHI TRA U D 9 9 050 Mr. Essix 2820 Cen- Lynwood,
Harris tury Bl. CA 90262
3 15-20K 68 PTB TRA U D 9 9 050 Gray Trk. 4280 Ban- Los Angeles,
Co. dini Bl. CA 90023
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FIGURE 3—Continued
Axle Weight Truck Cab Wheels State
Group Group Year Model Type LOG. Fuel Tot. Dr. Weight Name Address 1 Address 2
3 15-20K 67 KEN TRA U D
3 15-20K 69 FOR TMX U D
3 15-20K 66 AUT TRA N D
3 15-20K 71 KEN TRA U D
3 15-20K 72 KEN TRA U D
3 15-20K 69 WHI DIM U D
3 15-20K 72 WFT TRA C D
9 9 054
9 9 050
9 9 050
9 9 050
9 9 050
9 9 060
9 9 050
Ball Son
Transfer
Greenes
Ready Mixe'd
Griffith
Co.
J. V.
Trucking
Jersey Maid
Milk Prod.
Alusa West-
ern , In c .
Ameron
1136 Clint-
wood Av.
19030 S.
Normandie
Av.
3650 Cherry
Av.
510 W. 6th
St.
1040 W.
Slauson Av.
Box 575
400 S.
Atlantic
Bl.
La Puente,
CA 91744
Torrance,
CA 90502
Long Beach,
CA 90807
Los Angeles
CA 90014
Los Angeles
CA 90044
Azusa, CA
91702
Monterey
Park, CA
91754
15-20K 70 WFT TRA C D 9 9 054 Atlantic 515 S. Los Angeles,
Richfield Flower St. CA 90017
Co.
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-12-
TABLE 1
TRUCK ACQUISITION RESPONSE SUMMARY
No longer own or not in service . 20
Lease truck-owner not willing 12
No room in cab for observer 21
Too busy (too much trouble) 40
Don't want to be bothered 10
Unqualified refusal 9
Other reasons for refusal 3
Security problems 2
No longer business 4
.Several contacts and call backs with no response or decision 12
Not listed in telephone directory or unlisted number 2
Legal problems 5
Insurance problems 7
Union problems 3
TOTAL 150
Total sample available for testing out of 212 possible—62.
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-13-
FIGURE 4
AGREEMENT
This agreement is between
whose address is
and who is the owner or operator of a motor vehicle bearing the license
and hereafter referred to as owner, and Olson Laboratories
Incorporated, a corporation in the State of Minnesota, whose home of-
fice is 421 East Cerritos Avenue, Anaheim, California, and hereafter
referred to as the consultant.
The purpose of the agreement between the two parties is to describe
the participation of the owner in certain experiments to be conducted by
the consultant under a study sponsored by the U.S. Environmental Pro-
tection Agency. The experiment involves the instrumentation of the
owner's vehicle described above by the Environmental Protection Agency
and the placing of a consultant's observer on the vehicle as a passenger
during normal operations of the owner's vehicles, during days be-
tween and , hereinafter referred to as the experi-
ment period.
The owner agrees to deliver at his expense and using his driver,
the said vehicle to the consultant's facility at , on
between the hours of and for the purpose
of installation and calibration of equipment to automatically monitor
that vehicle's engine speed, vehicle speed, engine load factor and other
vehicle parameters by equipment and means provided by the Environmental
Protection Agency and the consultant.
The Environmental Protection Agency and the consultant agree to
perform this installation in a manner and location so as to not inter-
fere with the normal function or operation of the said vehicle.
The consultant will provide an observer during the experiment pe-
riod to ride on said vehicle during its normal operation and to make
such observations and enter into the consultant's log such data that
might be observed by him during the experiment period. The consultant
agrees that the observer will not engage in any other function than his
observation activity and the owner will not require the observer to en-
gage in any such activity other than that described.
The consultant will be responsible for all damages and liabilities
resulting from the installation, data recording and removal of equip-
ment on the owner's vehicle, and all actions of the consultant's employ-
ees, the consultant's subcontractor's employees, and other agents acting
for the consultant. The consultant will hold the owner free from per-
sonal and property damages and other liabilities related to said equip-
ment and the actions of the consultant's employees.
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FIGURE 't—Continued
The owner will hold the consultant free from any liabilities or re-
sponsibilities for any act or damages caused by or to the owner's vehi-
cle and employees, including delays, accidents, or other incidences re-
lated to all normal functions, operations and use of the said vehicle.
The rights in the data collected shall be vested in the consu]tant
and assignees for the purposes of the study, except however, the con-
sultant agrees not to identify or otherwise relate the owner or his em-
ployees to the data so collected without specific written permission of
the owner or the employee so involved.
To compensate the owner for all expenses involved in the participa-
tion in the experiment and all conditions related thereto, the consult-
ant agrees to pay to the owner the sum of within 30 days of the
conclusion of said experiment.
This agreement is accepted by both parties, this day ,
19 , and is executed in , in the county of
and the State of
Witnesseth:
For the Owner For the Consultant
OLSON LABORATORIES, INC.
By By
Title Title
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-15-
Vehicle inspection prior to installation, although planned to take
place two days before installation, was difficult to achieve in most
cases because it involved holding a vehicle out of service for one or
more hours while the inspection was performed. Owners who chose to
participate in the program did so somewhat reluctantly when told that
the vehicle would be out of service for from three to five hours on the
day of instrumentation installation. When asked to hold a vehicle out
of service for an additional period of time for an inspection, refusals
were quite common. In addition to owner reluctance, vehicle pre-inspec-
tion was discontinued in Los Angeles because in those instances where it
was performed and defects found that would influence the test if not
repaired, owners were not agreeable to making such repairs unless it
effected the normal work the vehicle was to do. For example, worn tires
that might blow during dyno testing but were considered acceptable for
normal driving would not be replaced, broken speedometer cables or
related parts were of no importance to owners from an operation stand-
point, but were vital to the survey needs. Whenever possible, items in
need of repair or replacement were put in operating condition by the
survey team at their expense, in order to prevent losing the use of the
vehicle. Obviously, this did not apply to high cost items such as
tires. When repairs were considered unreasonable and the owner could
not be persuaded to perform them, the vehicle was rejected and a replace-
ment vehicle located.
Calibration and installation of instrumentation was performed at
two (2) locations in Los Angeles. Each installation was equipped with
a Clayton tandom water brake chassis dynamometer. These dynamometers
were owned and operated by the 1) State of California Vehicle Mainte-
nance Department of the California Department of Transporation, located
in Hollywood, California, and 2) the California Air Resources Board at
El Monte, California. Five (5) sets of instruments were used in the
conduction of the survey. These instruments were mounted in the vehicle
in a location which allowed easy access by the on-board observer without
interfering with the driver. Vehicle scheduling depended totally on 1)
an instrument being available for use and 2) the ability of an owner to
deliver the promised vehicle. Initial operation program plans called
for the instrumenting of four vehicles per day (assuming instrumentation
availability) during normal working hours. In practice, however, only
two vehicles proved to be the practical extent to which instrumentation
installation could be expanded. This means that on the average four
trucks could be tested per week, instead of eight, the number originally
targeted.
Loss of a given day's operation for a vehicle because of instrument
failure, or vehicle breakdown required the slippage of all subsequent
vehicles. Most owners required a minimum of one day advance notice for
vehicle insturmentation. This was necessary to allow for scheduling of
a replacement vehicle to cover scheduled routes or tasks for that com-
pany's operation during the four to five hours required for instrument
installation. In most cases, if slippage occurred due to a loss of data
-------
-16-
it was not known until late in the day. This meant owners scheduled for
installation the next day were unavailable and cancellation of that
vehicle meant a loss of as many days as needed for rescheduling or
replacement. Close control of instrument repair, and quick response to
in-operation failure reduced loss time substantially in Los Angeles,
however, a total of fourteen (14) days were lost to this problem.
E- Vehicle! Calibration
As will be discussed in more detail later in this report, the
primary data parameters collected in the CAPE-2.1 survey were:
\
1. Road speed,
2. Load factor, and
3. Engine RPM.
Of the three parameters, load factor represented the most difficult
parameter to measure. The reasons for this stem from the fact that when
testing heavy-duty engines for compliance with emission control regula-
tions, an engine dynamometer is used to exercise the engine through the
test procedure. Power measurements are then engine shaft power.
For economical as well as practical reasons engine shaft power mea-
surements were not possible while the vehicle was being operated in
normal use as in the Los Angeles or CAPE-21 study. An alternative solu-
tion then would be to measure some other parameter more easily accessible
and relative to engine shaft horsepower.
The relationship between fuel flow and power in diesel engines as
well as manifold pressure in gasoline engines is well known in the
automotive industry and was therefore used in the CAPE-21 study. This
alone did not completely solve the unique problem created by the CAPE-21
program structure because the program did not allow for removal of the
engine from the vehicle for calibration of the load factor measurement
with shaft horsepower.
It was decided that calibration of load factor measurements could
be accomplished by relating load factor measurements to the vehicles
rear wheel horsepower and later adding the characteristic losses in
transmissions, and differentials (i.e., drive train) to arrive at shaft
horsepower. This assumption holds true when horsepower is expressed in
terms of percent of maximum wheel horsepower and must equal 100% or
maximum shaft horsepower, and can be expanded to intermediate power
settings if one assumes the same relationship at all intermediate powers,
i.e., drive train losses are linear with RPM. Later in other reports
dealing with the CAPE-21 data analysis , this assumption will be shown
to be false, but for discussion purposes, it will be maintained here.
F. Data Acquisition Package
The data acquisition system used included sensors to measure engine
-------
-17-
RPM; vehicle speed; engine load factor; engine.temperature; and throttle
valve position; sensor signal conditioning electronics; and a digital
data logger with integral clock and magnetic tape recorder. Manually
operated switches were included to enable recording of road type and
traffic conditions for subsequent correlation with the sensor data. The
above signals, along with time of day from the data logger clock, were
sampled and recorded at the rate of one data set every 0.863 seconds.
A system block diagram is shown in figure 5.
1. Data Logger
The central component of the data acquisition system is the Metra-
data Model DL620B Data Logger, figure 6. This unit accepted eight
differential data inputs of 0 to + 1 Vdc, scanned them sequentially, and
converted the analog signal to a 16-bit (3 digits plus sign) digital
signal. These eight channels, plus two channels of time, pre-parity,
and parity bits, were assembled into a scan which was recorded at a rate
of 1.2 scans per second. This digital data was recorded on a 4-track,
1/4-inch tape in a BCD complement format at a density of 150 bits per
inch. The tape was loaded in a 1200-foot endless loop cassette, which
provided 12 hours of continuous recording. Front panel controls on the
Data Logger included the POWER switch, Analog Display with CHANNEL
SELECT switch, and TIME SET controls. Time was displayed on Channels 1
and 2 in the same manner as other channels. The channel format for all
tests has been listed in Table 2.
2. Signal Conditioning Module
Signals from the transducers were fed into the Signal Conditioning
Module. The Signal Conditioning Module provided interfacing and conver-
sion between transducer and data logger.
3. Power Supply
A separate 12 V battery powered the data acquistion system, and was
controlled by a front panel switch. An indicator switch showed system
power status.
4. Road Type and Traffic Conditions
Manual inputs for road type (freeway arterial and local) and traf-
fic conditions (heavy, medium, and light) were programmed by two sets of
switches on the front panel of the signal conditioner. These switches
were operated by the on-board observers, and were interlocked to prevent
selection of more than one condition for either of the two parameters.
Selection of a given road type or traffic condition switch applied one
of three voltages to the recorder coded as follows:
-------
-18-
VEHICLE
SPEED
FILTER
RPM
LOAD
FACTOR
IDLE
STOP
SWITCH
ENGINE
TEMP.
F/V
CONVERTER
L
ATTEN-
UATOR
F/V
CONVERTOR
ATTEN-
UATOR
± 15V
CONVERTER
WYLE
MANUAL
SWITCHES
5 VOLT
REG
SIGNAL CONDITIONER
12V
BATTERY
"I
VEHICLE
BATTERY
DL-620-B
DATA
LOGGER
FAN
FIGURE 5
Block Diagram - Data Acquisition System
-------
-19-
1. System Power
2. Manual Input - Traffic
3. Manual Input - Road Type
4. Power Indicator
5. 5 Amp. Power Fuse
6. RPM Sensitivity Adjust
7. Load Factor Sensitivity
8. Vehicle Speed Adjust
9. Inverter Power Fuse
10. Illuminated Power Switch
11. Illuminated Mode Switch -
Standby/Record
12. Record Rate Switch (locked)
13. Thumbswitches to set Real Time
14. Time Reset Button - Starts Real Time
15. Channel Select - Displays in Item 16
16. Channel Data Display 3-Digit + Sign
17. Polarity Display - Lights on (-)
18. Cassette Release Lever
19. Mode Test Switch
FIGURE 6
-------
-20-
TABLE 2
CHANNEL ASSIGNMENTS DURING CALIBRATION
Channel No. Measurement
1 Truck No. and Time (hours tens)
2 Time (hours units and minutes)
3 Engine RPM
4 Load Factor
5 Vehicle Speed
6 Road Type
7 Traffic Conditions
8 Slow Idle Position
9 Engine Temperature
10 Channel 5 Techgenerator Verifi-
cation
-------
-21-
Selected Coded Input
Switch Condition Voltage Level
Road type Freeway -860 + 30 mv
" Arterial 0 + 30 mv
" Local +860 + 30 mv
Traffic Condition Light -860 + 30 mv
" Medium 0 + 30 mv
" Heavy +860 + 30 mv
5. Vehicle Speed
The input signal for vehicle speed was an AC signal from a Shaft
Encoder. The frequency of the encoder was converted to a voltage level
which was proportional to vehicle speed.
A recurrent problem with vehicle speed shaft encoders producing an
output when the vehicle was not in motion was experienced during field
operations. The problem was solved by installing an additional speed
transducer, of the tachometer-generator type, in the speedometer cable
drive. The output from this transducer was connected to Channel 10 on
the data logger to indicate when the vehicle was stopped. The tachometer
generator output was reliably zero when the vehicle was stopped. The
presence of a signal from this unit was used to confirm the validity of
the Channel 5 readings.
6. Engine RPM
The engine RPM input was derived from the ignition coil or a shaft
encoder and was a series of pulses with a DC level of 0.5 to 6 volts and
a frequency proportional to RPM. The resultant pulse train was converted
fo a DC signal proportional to input frequency by a frequency to voltage
(F/V) converter and adjusted to a scale factor approximately 0.1 v/1000
RPM. An alternate RPM input to the Signal Conditioner was provided for
on vehicles with mechanical tachometers. For engines which had a mechan-
ical tachometer drive, engine RPM was measured by use of an optical
shaft encoder.
7. Load Factor
Load factor signal sources were pressure transducers for gasoline
and Cummins Diesel engines, and a displacement transducer for Detroit
Diesel engines.
a. Gasoline Engines - The engine load factor for gas engines was
obtained using a Bourns Model 556 Pressure Transducer with a range of 0-
15 psig to measure intake manifold pressure. The unit was mounted on
the inside of the signal conditioning box. The transducer connected to
the intake manifold with a section of 1/4-inch automotive vacuum tubing
approximately ten feet long. A snubber valve was placed in the vacuum
-------
-22-
line to protect the transducer from damage.
b. Detroit Diesel Engines - The engine load factor for Detroit
Diesel engines was obtained by measuring the angular displacement of the
rack using a Research Inc. Model 4045-3 linear displacement transducer.
The "rack" is a mechanical device which alters the settings of the
engines fuel injectors thereby changing the fuel charge to the cylinders
which in turn control the available engine power.
c. Cummins Diesel Engines - The load factor transducer for Cummins
Diesel engines was a 0-300 psig pressure transducer measuring rail
pressure at the fuel pump outlet. The transducer used was a Viatran
Model 218-12 strain-guage type. Rail pressure is the measurement of
fuel pressure present in the fuel manifold to the engines fuel injection
valves. This pressure varies as a function of throttle movement which
in turn controls fuel pump pressure. Rail pressure is, then, directly
relatable to engine horsepower and RPM.
8. Throttle Valve Closure
A microswitch, installed on the carburetor throttle linkage was
used to sense closed throttle condition. This generated a step function
voltage input to the signal conditioner to be recorded in Channel 8 to
indicate closed throttle conditions.
9. Engine Temperature
To sense engine temperature, a themistor unit, type ID751 (National
Laboratories Industries) was clamped to the coolant output header as
close to the engine as possible. This unit provided a scaled analog
voltage proportional to coolant temperature.
G. Support Equipment and Personnel
Support equipment used in the execution of the survey can be
divided into three categories:
1. Instrumentation,
2. Transportation and,
3. Communications.
a. Support Equipment (Instrumentation)
Support equipment for the instrumentation ranged in type from
standard electronic test equipment (volt meters, counters, function
generators, etc.) used in basic trouble shooting and calibration, to a
specially designed cathode ray tube (CRT) display used in verifying tape
quality. Two heavy-duty chassis dynamometer were used in the vehicle
calibration procedure. A listing of the major pieces of test equipment
and their general use has been shown in Table 3.
-------
-23-
TABLE 3
MAJOR TEST EQUIPMENT REQUIREMENTS
Cathode ray tube cassette
reader
Dead weight pressure standard
Function generator
Tandom chassis dynamometers
Varian model mini computer
system
Use
Tape quality control
Fuel pressure transducer cali-
bration
Calibration of D/A converters
(signal conditioners)
Horsepower calibration of in-
strument installations
1/4 to 1/2 inch tape conversion
-------
-24-
B. Support Equipment (Transportation)
Seven (7) vehicles were used to support the Los Angeles program:
two (2) equipment, vans, three (3) leased passenger cars, and two (2)
General Service Administration (GSA) cars. A total of fifty-four
thousand miles was driven in the vehicles during the program. The vans
were equipped as portable instrument labs and carried a complete set of
test equipment used in the service, maintenance, and calibration of the
on-board recorders. These vehicles were primarily used during installa-
tion and maintenance operations, but were sometimes used as backup
vehicles for servicing. Four of the five passenger cars were used as
chase vehicles which meant they were the prime mode of transportation
used when a test vehicle developed trouble while in the performance of
its normal work duties. These vehicles were also used for performing
normal on-board instrument servicing such as changing tape cassettes and
batteries, and performing in-service checkout. A third use of these
vehicles was to transport data tapes to the processing center. The
fifth passenger car was used in the management of the program.
C. Support Equipment (Communications)
As mentioned earlier, the California program was totally dependent
on operator participation for its success. In view of this, every
effort was made to insure that once a vehicle was instrumented it com-
pleted its test period on schedule.
One important part of meeting schedules was the ability to respond
to any situation which threatened to alter the schedule in any way. To
accomplish this, a communication system was put into use which allowed
all personnel to be in contact with each other and the program manager
in a minimum amount of time (usually five (5) minutes) twenty-four hours
a day. An area paging system was employed and each man on the two
technical crews used in Los Angeles was given remote pagers. In addi-
tion to this, the project manager's vehicle was equipped with a mobile
telephone which allowed him to communicate with any crewmember while en-
route to or from any trouble spot. On-board observers could, using
either the paging system or calling the mobile operator, contract any
key survey personnel at any time to report problems with in service test
vehicles.
D. Personnel
The personnel requirement for the Los Angeles survey consisted of
technical as well as unskilled individuals. Two (2) crews of four
qualified test technicians were used for equipment maintenance and
installation. Five non-skilled persons were employed to act as on-
board observers. Their responsibilities included operational monitoring
of test equipment, manual input of selected data, and the manual record-
ing of route information. In addition to these tasks, the observers were
used as runners for tape delivery, parts and equipment pick-up, and
general program assistance.
-------
-25-
e. Program Logistics
In addition to the responsibility of arranging for the acquisition
of test vehicles, OLI was also responsible for the program logistics.
The question of logistical control was given highest consideration early
in the program because of the early recognition of the problem of owner
and program manager relations. The necessity for fast turnaround on re-
quest for equipment and personnel demanded that normal delays in these
areas be reduced to bear minimums wherever possible. The use of OLI for
purchasing, manpower acquisition, payroll administration, equipment ren-
tals etc. proved to be the soundest approach to on-time completion of
the program. Normal governmental channels would not have allowed this.
-------
-26-
III. Data Collection ,
A. Type of Data
As previously mentioned, the CAPE-21 data base was intended for use
in the development of heavy-duty test cycles for engine and/or chassis
dynamometers. The optimum goal in the cycle development program was to
develop cycles which are representative of the way heavy-duty vehicles
are operated in normal service. To accomplish this, the Los Angeles
portion of the CAPE-21 study was conducted using commercially owned and
operated vehicles selected at random and operated in the normal service
of the company by the company's normal drivers. Every precaution was
taken to prevent interference with the operation of the driver of the
vehicle during the survey period of a given vehicle. The primary data
collected in the survey were that data which were considered vital to
the testing of emission characteristics of heavy-duty engines or vehi-
cles. These data consisted of RPM, load factor, and road speed measure-
ments. The remaining data collected in the Los Angeles survey were time
of day, road type, traffic condition, relative engine temperature,
throttle closure, and vehicle identification. It is important that the
logic associated with the methodology used in data collection and the
type of data collected be reviewed at this time in order to clearly
indicate the limits of the data base.
1. Vehicle Identification
Each vehicle tested in the Los Angeles survey was assigned an
identification number. A complete listing of the vehicles tested in
Los Angeles is given in table 4.
2. Time of Day
Time of day for operating periods was recorded in hours and minutes
from a twenty-four hour interval clock. Since the data scan rate is
.864 seconds, the time between minutes for any given scan location can
be calculated. The scan rate was also used as a back-up for the normal
time channels, hence data tape rejection for time channels was not
necessary.
3. Engine RPM
Engine RPM was recorded in millivolts at a 10:1 ratio (RPM/milli-
volts). Because RPM was a pulse derived signal in all cases, precision
calibration of the signal conditioner was achievable by use of a variable
frequency function generator and an event/unit time counter (EPUT).
Input versus output data was manually recorded during calibration so
that crosschecking of the RPM to millivolt conversion could be accom-
plished at a later date, should the need arise.
-------
-27-
TABLE 4
LOS ANGELES TRUCKS BY MANUFACTURER OF ENGINE
Manu-
facturer
Ford
Ford
Ford
Ford
Ford
Ford
Ford
Ford
Ford
Ford
Ford
Ford
Ford
IH
IH
IH
IH
IH
IH
IH
IH
Com.
Com.
Com.
Com.
Com.
Com.
Com.
Com.
CMC
CMC
Truck
Number
7
10
11
12
16
17
18
19
24
28
35
39
48
Ford
Engine CID/Fuel
V8-390/G
V8-352/G
V8-330/G
V8-532/G
V8-225/D
V8-330/G
V8-150/D
V8- /G
V8-361/G
V8-391/G
V8-391/G
V8-534/G
V8-361/G
International Harvester
8
13
14
21
26
40
43
47
9
20
31
34
37
38
44
46
V-549/G
I6-265/G
V-304/G
V8-345/G
V-304/G
V-345/G
V-549/G
V-304/G
Commins Engine
NTC335/D/855
NTC350/D/855
NH220/D/743
NTC290/D/855
NTC335/D/855
NH250/D/855
NHC250/D/855
NHC250/D/855
General Motors
Year
1973
1965
1972
1966
1968
1974
1972
1964
1971
1971
1967
1964
1968
1968
1969
1973
1970
1974
1970
1971
1969
1963
1973
1969
1969
V6-305/G
V6-351/G
1970
1970
-------
-28-
TABLE 4—Continued
Manu-
facturer
CMC
CMC
CMC
CMC
CMC
CMC
DDAD
DDAD
DDAD
DDAD
DDAD
DDAD
DDAD
DDAD
DDAD
DDAD
Dodge
Truck
Number
4
5
25
30
32
42
6
15
22
23
27A
27
29
41
41A
45
Engine CID/Fuel
General Motors
V8-350/G
I6-250/G
V6-305/G
V6-351/G
V8-350/G
V8-366/G
Detroit Diesel
8V71/568/D
8V71N/568/D
8V71/568/D
8V71/568/D
8V71/568/D
8V71/568/D
8V71T/568/D
8V71/568/D
8V71/568/D
8V71/568/D
Dodge
36
V8-318/G
Year
1971
1974
1967
1970
1972
1960
1974
1963
1974
1973
1973
1973
1971
1974
1969
G
D
Gasoline
Diesel
-------
-29-
4. Load Factor
Load factor measurements taken in the Los Angeles portion of the
CAPE-21 program were designed to relate rear wheel horsepower measure-
ments to one of three (3) engine parameters depending on the engine fuel
system. As discussed in section II F-7, the three fuel systems were:
a. Manifold vacuum in the case of gasoline engines,
b. Rail pressure in the case of vehicles equipped with Cummins
Diesel engines, and
c. Rack position in the case of vehicles equipped with Detroit
Diesel Allison division Diesel engines.
As previously discussed in section E of this report, it was ori-
ginally proposed that load factor data recorded during the survey be
converted to engine shaft horsepower through the use of math models
derived for each vehicle from calibration data on that vehicle; i.e.,
engine shaft horsepower, can be considered linear to rear wheel horse-
power at all RPMs when normalized to maximum power. This proposal was
found to be inadequate in later phases of the data analysis program and
the final procedure adopted is discussed in two EPA reports on the
subject-^ > 4 which deal with the specifics of horsepower modeling tech-
niques.
5. Road Speed
Vehicle road speed was taken from the speedometer take-off at the
vehicle transmission or front wheel take-off in those vehicles so equip-
ped. The accuracy associated with this measurement is equivalent to
that associated with SAE standards for motor vehicle speed measurement
systems. Some vehicles, however, were equipped with two speed uncom-
pensated rear-ends which, under normal circumstances, introduce an error
in the speedometer, and hence the road speed data. This error was
corrected for in the CAPE-21 survey by the use of a road speed compen-
sating network, which was manually activated by the on-board observer
whenever the axle was placed in high gear by the driver.
6. Road Type
Road type information is a manual input accomplished by the on-
board observer. Instructions to these observers on the operation of the
switches controlling this input included not placing a road type switch
in the "on" position until such time as the vehicle was actually on the
particular road type indicated by that switch (i.e., freeway, arterial,
or local street). This proved to be a most difficult requirement to
control from the standpoint of accuracy in total time spent on a parti-
cular road type. For example, there is no way to determine precisely
where the observer decided to change from one road type to another,
-------
-30-
i.e., at the on ramp to a freeway or after completing the merge with
freeway traffic. Obviously, the total time associated with a given road
type will depend on such a decision. Depending on the importance placed
on this parameter by a user of this data during data analysis, a certain
degree of special editing may be required to insure accuracy levels
desired.
7. Traffic Condition
Traffic conditions were recorded in the same manner as was road
data, that is, it was a manual input. It therefore, is subject to the
same limitations in accuracy as the road type inputs discussed in item
6 above.
8. Throttle Position
Throttle position is a measure of driver demand rather than true
throttle position. The measurement involves a detection system which
simply indicates when the throttle is on the low speed stops, i.e.,
there is no demand for drive power.
9. Engine Temperature
Engine temperature is a relative measurement of thermal operating
conditions. Because the sensing device was not physically located in
the engine coolant system, only temperatures relative to ambient can be
relied on, i.e., engine compartment temperatures which are predominantly
made up of engine block temperature, but which are effected by temper-
atures associated with other devices in the engine compartment. Cold,
warm, and hot operations can be identified by establishing cut points in
temperature spreads, but assumed accuracies in absolute temperature
beyond this is not recommended.
B. Data Format
The data from the Los Angeles survey were stored on 1/4-inch mag-
netic tape cassettes.
1. Signal Levels and Recording Format
Data from each transducer were converted to single levels of 0, +
or -1 V. The signals from the ten data channels were then multiplexed
and converted to Binary Coded Decimal (BCD) form and recorded serially
in four bit words, 4 bite/channel, see figure 7. Each data scan con-
sisted of 56 words, thirty (30) data words (3 per channel x 10), eight
sign words (one per channel except time and vehicle ID), and one pre-
parity word and one parity word. The data are recorded in complement
format at a density of 150 bits per inch.
C. Data Processing
Because the format described in Section Bl was not acceptable to
-------
-31-
•'/V'TAPE
BCD
8
DECIMAL
CHANNEL
Ill II III III
+200+815+710-526-000+1 34-000-825+1 11+000
i i i i i i i i i I !
I 234567 89 10?
I DATA SCAN
a:
Q.
IDEALIZED CASSETTE DATA FORMAT
-------
-32-
FIGURE 8
CASETTE CONVERSION - ZERO SCAN OUTPUT
Truck 3 Day 2
I J>0
00058
00004
00001
ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ
zzzzzzzzzzzzzzzzzzzzzz 0001
zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz
zzzzzOOOOl
zzzzzzzOOOOl
zzzzzzzzzzzOOOOl
zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz
zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz
zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz
00001
zzzzzzzzzzzzzzzzzzzzzOOOOl
zzzzzzzOOOOl
00001
zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz
zzzzzzzzOOOOl
zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzOOOOl
zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz
zzzzzzzzzzzzzzz PE 0
RUN 7
SC 34,436
EC 78
-------
-33-
most Automatic Data processing machines, a conversion process was re-
quired to convert the tape cassettes to, in this case, 9-track IBM com-
patible format.
During the conversion process a number of tests were performed on
the data to establish the acceptability of the'recorded information.
These tests did nothing to substantiate the validity of the recorded
data, but merely determined if, in fact, the recording format was cor-
rect. A test of this type was necessary because 1) the recorder when
subjected to electrical noise could write erroneous data bits or char-
acters, 2) the parity and/or pre-parity bits could be in error invali-
dating a particular data scan; and 3) the recorder had no provisions for
read after write operation, and recorded data tapes were susceptible to
skew errors caused by read head misregistration.
The test performed in the conversion process were:
a. "Z" test, this test checked the validity of a scan by checking
the parity against the bit count in the scan. If the bit
count did not match the parity word the scan was set to zero.
The "Z" test, shown in figure 8, simply counted the number of
zeroed records in a block of 60 consecutive records and
printed a Z if none were zeroed, or the number equal to the
total number of zeroed records counted.
b. Acceptance criterion check. This test, based on the "Z" test,
rejected a tape if the total number of zeroed scans exceeded
10% of the total scans for the tape.
c. Readability check. This check consisted of dumping every 20th
record to insure that the transcription process was producing
a good IBM tape.
One additional task was performed during data processing, that task
consisted of adding a header to the IBM tape which identified the vehicle
by test number, indicated the number of days the vehicle was to be
tested, and indicated the type of vehicle, i.e., Diesel or gasoline,
number of cylinders, and the license number of the vehicle.
D. Data Tape Quality Control
To insure delivery of the best possible quality in data tapes to
the processing center, a quality control process was used to allow
rejection or acceptance of data tape cassettes in the field. The
quality control procedure was also used as a diagnostic tool for iso-
lating problems in instrumentation as well as personnel errors.
An on-board observer was assigned to each test vehicle. The ob-
server was present at instrument installation and remained with the
vehicle throughout testing. During testing it was the responsibility of
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-34-
each observer to read and manually record each data channel every thirty
minutes. Because the readings taken from the recorder display did not
reflect what was being written on tape (the recorder did not have read
after write capability), a cathode-ray tube (CRT) display system was
used to read each cassette after a days running. The CRT's electronics
were programmed to read each scan of data and display that line, then
when the parity word was read the CRT retraced and began writing the
next scan of data directly under the first. If for any reason the
parity word was incorrect there would be no retrace and the next line of
data would be displaced indicating an error. Since the time channel
could be used for locating any point in the data within 51 seconds
(seconds were not recorded), the observer's log could be used to verify
the approximate data that should have appeared on tape at a given time.
Using the CRT and the observer log, data tapes were checked after
each days run. If for any reason the tape was found to be defective a
decision was made as to what course of action could be taken to prevent
loss of the vehicle to the survey, or the instrumenting of a new vehicle
waiting for an entrance into the survey.
E. Resultant Data Base
At the end of the Los Angeles survey fifty-six vehicles were tested,
the breakdown of which is:
1. 48 urban operated trucks,
2. 5 city buses,
3. 2 over-the-road (long haul) trucks (not intended for use in
cycle development data base) and,
4. 1 over-the-road (long haul) bus.
Table 5 shows the final data base description.
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-35-
TABLE 5
Truck
Number
1
1
1
1
1
1
2
2
3
3
3
4
4
4
5
5
5
6
6
6
7
7
7
7
8
8
8
8
9
9
9
9
9
10
10
10
10
11
11
11
11
Day
Number
4
5
6
7
8
9
2
3
1
3
4
1
2
4
1
2
4
1
2
3
2
3
4
5
1
2
3
4
1
2
3
4
5
1
2
3
4
2
3
4
5
Tape
Error*
1
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Total Zero
Scans
154 + 60
206
308
70
116
41
58
56
30
76
38
12
122
46
133 + 60
62
121
78
19
33
66
17
20
22 + 60
914
17
140
102
103
30
1,257
5,715
3,086
357
1,012
37
25
21
730
86
42
Total
Scans
23,758
44,446
28,162
26,211
38,328
26,628
19,260
20,228
22,672
16,742
5,008
7,834
17,162
16,809
12,049
5,820
8,070
22,668
18,664
24,771
4,529
23,714
21,624
22,008
29,573
32,074
35,929
31,954
31,648
27,468
27,667
40,110
40,018
11,213
21,918
14,686
13,300
19,897
18,523
17,667
16,378
*Note: If an error on 9-track tape happened during translation, the num-
ber of scans appears and 60 scans are added to the total zero scans for
every tape error. 1 Record = 60 scans on 1/2 inch 9-track tape.
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-36-
TABLE 5—Continued
Truck
Number
11
12
12
12
12
13
13
13
13
14
14
14
14
15
15
16
16
17
17
17
17
17
18
18
18
19
19
19
19
19
20
20
20
21
21
21
21
22
22
23
23
24
24
24
Day
Number
6
1
2
3
4
1
2
3
4
5
6
7
8
1
2
1
2
1
2
3
4
5
2
3
4
1
2
4
5
6
2A
2B
3
1
2
4
5
1
3
1
2
1
2
3
Tape
Error*
0
0
0
0
0
2
1
1
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
2
0
0
0
0
0
0
0
0
0
0
Total Zero
Scans
6
131
139
195
26
6 + 120
77 + 60
77 + 60
25
22
17
11
17
58
48 + 60
17
39
245
12
37
4,451
360
15
88
32
110
19
57
50
11
486
12
993 + 60
33 + 120
25
48
28
72
399
171
497
35
22
269
Total
Scans
37,027
18,989
19,260
23,602
22,566
15,253
20,389
13,109
17,172
14,880
12,030
16,044
22,731
22,822
26,409
16,975
27,960
19,687
8,785
17,099
15,263
16,982
13,176
8,360
13,919
7,844
13,369
10,098
14,241
8,045
15,490
1,672
17,365
22,099
15,459
15,684
17,104
42,126
34,938
16,909
20,336
25,586
23,870
19,948
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-37-
TABLE 5—Continued
Truck Day Tape Total Zero Total
Number Number Error* Scans Scans
24 4 0 23 25,166
25 1 0 1,384 9,190
25 2 0 19 21,027
25 3 0 2,766 18,388
25 4 0 10 7,751
25 5 0 16 16,187
25 6 0 13 22,212
26 1 0 34 9,250
26 2 0 20 15,827
26 3 0 10 19,095
26 4 0 5 8,009
26 5 1 20+60 12,815
27 1 0 17 21,949
27 2 0 137 11,870
28 1 0 17 6,140
28 2 1 78+60 6,374
28 3 0 118 9,454
28 4 0 86 6,464
28 5 0 116 7,373
28 6 0 77 15,848
29 1 0 86 18,242
29 2 0 88 17,203
29 3 0 26 20,306
29 4 0 171 30,024
29 5 0 15 15,381
29 6 0 33 16,750
30 1 0 332 21,104
30 3 0 47 31,776
30 4 0 238 29,828
31 3 0 19 15,970
31 4 0 13 14,327
31 5 1 28+60 34,032
32 1 0 13 4,872
32 2 0 11 10,354
32 3 0 29 8,445
32 4 0 29 7,287
34 1 0 7 21,876
34 2 0 20 22,802
35 1 0 1,386 15,945
35 2 1 1,335 + 60 15,437
35 3 0 670 15,633
35 4 0 947 21,393
36 2 0 79 15,416
36 3 0 603 18,186
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-38-
TABLE 5—Continued
Truck
Number
36
36
37
37
37
37
37
38
38
39
39
39
39
40
40
40
41A
41A
41
41
42
42
42
42
43
43
43
43
44
44
44
44
44
45
45
45
45
45
46
46
47
47
47
47
Day
Number
4
6
1
2
3
4
5
1
3
1
2
3
4
1
2
3
1
2
2
3
2
3
4
5
1
2
3
4
1
2
5
7
11
3
4
5
6
7
1
2
2
3
4
5
Tape
Error*
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2
1
0
0
1
0
0
0
Total Zero
Scans
6
43
66
142
25
103
10
119
47
24 + 60
21
217
23
21
322
144
808
25
34
3,596
4,160
43
22
30
1,817
1,151
492
838
12
18
46
9
222
41
102
40
13 + 120
463 + 60
48
169
43 + 60
641
63
16
Total
Scans
23,409
7,496
24,606
29,331
26,279
28,541
37,141
11,645
3,895
25,631
27,628
12,202
21,228
13,580
13,029
13,377
15,857
12,476
13,295
18,696
10,358
8,618
7,903
9,469
36,329
12,274
11,556
13,239
6,215
10,356
12,951
6,546
14,439
15,174
25,914
40,256
38,156
27,471
14,727
17,645
10,952
19,554
15,862
16,941
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-39-
TABLE 5—Continued
Truck
Numbei
48
48
48
48
48
51
51
80
85
85
85
85
85
85
85
Day
Number
1
2
3
4
6
1
2
1
1
2
3
4
5
6
7
Tape
Error*
0
1
0
1
2
0
1
0
0
0
0
0
0
0
0
Total Zero
Scans
159
52 + 60
25
28 + 60
37 + 120
36
25 + 60
36
61
42
19
50
44
99
18
Total
Scans
14,582
10,560
14,441
9,273
17,809
21,437
23,089
35,896
15,324
38,363
35,640
19,459
41,146
31,600
33,816
Bus
Number
90
90
90
91
91
91
92
92
92
93
93
94
94
94
95
95
Day
Number
1
2
4
1
2
3
3
4
5
1
2
2
3
1
1
2
Tape
Error*
0
1
0
0
0
0
1
1
0
0
0
1
0
1
0
0
Total Zero
Scans
403
24
101
78
48
152
51 + 60
20 + 60
209
77
93
102 + 60
166
199 + 60
32
5
Total
Scans
17,468
24,418
25,560
58,658
57,658
56,808
45,469
12,298
40,058
50,167
49,707
46,725
43,084
44,693
84,198
19,408
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-40-
IV. Summary
The combined, New York and Los Angeles CAPE-21 data base, repre-
sents the most comprehensive in-use heavy-duty truck study ever under-
taken by any segment of the heavy-duty truck industry. There are still
those who would comment that it is not complete. In any study of this
magnitude, cost is the greatest restrictor to completeness, as was true
in this case. The data collection, in the case of the CAPE-21 study,
was confined to the needs of EPA for a data base designed for use in
cycle development for heavy-duty truck testing. From this standpoint,
the major parameters of interest were engine RPM, load factor, and
vehicle speed. Other parameters measured during the survey may be used
separately or in conjunction with the primary parameters, but only with
a great deal of discretion.
Every possible precaution has been .taken to insure that the data
collected was of exceptional quality and presented in its purest form.
But this is not to suggest that it was intended for use in all phases of
heavy-duty truck testing or development. As previously mentioned, this
report deals only with the particulars of data collection, the analysis
of the collected data is the subject of another report, and will be
presented at a later date. For this reason no reference has been made
to any conclusions as to the validity of the data or its ability to meet
the requirements of the cycle development goals of EPA.
-------
LIST OF REFERENCES
1. Heavy Duty Vehicle Driving Pattern and Use Survey: Part I. New
York. EPA Report APT. D-1523, Wilbur Smith and Associates, May
1973.
2. Heavy Duty Vehicle Driving Pattern and Use Survey: Part II. Los
Angeles Basin, EPA Report EPA-460/3-75-005, Wilbur Smith and
Associates, February 1974.
3. Engine Horsepower Modeling for Gasoline Engines, EPA Report
HDV 76-04, Leroy Higdon, December 1976.
4. Engine Horsepower Modeling for Diesel Engines, EPA Report HDV
76-03, Chester J. France, October 1976.
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