r
ANALYSIS OF THE
RELATIVE EFFECTIVENESS OF DIFFERENT
SHORT TESTS
FOR 1980+ VEHICLES
DRAFT REPORT
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-------
ANALYSIS OF THE
RELATIVE EFFECTIVENESS OF DIFFERENT
SHORT TESTS
FOR 1980+ VEHICLES
DRAFT REPORT
Prepared for:
ENVIRONMENTAL PROTECTION AGENCY
Ann Arbor, Michigan
under Subcontract to:
SIERRA RESEARCH
Sacramento, CA
Prepared by:
ENERGY AND ENVIRONMENTAL ANALYSIS, INC.
1655 North Fort Myer Drive, Suite 600
Arlington, Virginia 22209
February 7, 1995
-------
ANALYSIS OF THE RELATIVE
EFFECI1VENESS OF DIFFERENT SHORT TESTS
FOR 1980+ VEHICLES
1. OVERVIEW OF TEST PROGRAM
The analysis of the effectiveness of different short tests is based on actual test data
obtained from California. The database consists of 640 vehicles tested through late
December 1994 at the Air Resources Board’s Haagen-Smit Laboratory (HSL) in El
Monte, California. The 640 vehicles are part of a random sample of 2,000 vehicles taken
from a list of 2,000,000 vehicles which were due for biennial I/M testing and were
garaged within a 25-mile radius of HSL The list of vehicles was provided to ARB by
the California Department of Motor Vehicles (DMV). The owners of the vehicles were
notified of inclusion in the test program via a solicitation letter, which instructed them to
bring the vehicle to HSL for testing. The letter also offered a list of incentives to the
vehicle owners.
When a vehicle was brought into HSL for testing, it was put through a series of
screening tests. First, the vehicle was inspected for safety and testability. If the vehicle
was determined to be safe and testable (or could be repaired to such a state), it was then
given an underhood inspection, including the assessment of evaporative emission control
system accessibility. The vehicle engine was allowed to idle throughout the screening
process and was turned off only if the underhood inspections required doing so.
Except for those vehicles which were given pre-test repairs, the testing sequence was to
begin within 20 minutes of the vehicle’s arrival at HSL In the event that the screening
process took longer than 20 minutes, the affected vehicles were to be given a “Second
Chance” test (i.e., the first 1M240 or ASM test was used as a conditioning test only, and
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the results from a second test were recorded). If more than 40 minutes elapsed prior to
testing, affected vehicles were to be warmed up with on road driving. It is not known
how many (if any) vehicles were given second chance tests, nor how many had to be
warmed up with on road driving.
After completing the screening tests, accepted vehicles were tested in as close to “as
received” condition as possible using the tank fuel. When necessary, tank fuel was
supplemented with commercial gasoline or gasoline from HSL’s underground storage
tanks. Vehicles were then given ASM 2525, ASM 5015, and 1M240 tests; vehicles with
even test numbers had the ASM tests performed first, and odd numbered test vehicles
had the 1M240 test performed first. FTP tests, when performed, were administered after
the ASM and 1M240 tests. For this analysis, only the “as received” test data was utilized
to compute the effectiveness of short tests. This analysis focused on only 1980 + vehicles
featuring “closed loop” emission controls, although additional analysis may be performed
in the future for oxidation catalyst equipped 1980+ vehicles and pre-1980 vehicles.
2. DESCRIPTION OF DATA AS RECEIVED
The emissions test results for the 640 vehicles tested through late December was
“preliminarily screened” by ARB and provided on five diskettes. The first two diskettes
contain data relating to ASM and 1M240 repairs, and the third diskette contains Smog
Check data on vehicles tested at ARB. The fourth diskette contains the 1M240, ASM,
and FTP test results, and the vehicle description data. The fifth diskette contains
information on any pre-acceptance repairs performed, a list of the vehicles placed into
the 1M240 and ASM bins, and the cutpoints used to determine if a vehicle failed the
1M240, ASM 25/25, or ASM 50/15 tests. As this phase of the task is an analysis of
baseline emissions, the data files on the first three diskettes were not used.
The flies on diskettes four and five that were used in this analysis are:
FTPDKP.XLS - FTP results at baseline (as received) and after repair.
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• IM24ODKP.XL.S - 1M240 results at baseline and after repair.
• T1TEST.XLS - ASM 50/15 results at baseline and after repair.
• T2TEST.XLS - ASM 25/25 results at baseline and after repair.
• VEHDESC.XLS - vehicle description data.
• CUTPOINT.XLS - model year grouped cutpoints, by inertia weight, for
ASM and 1M240 tests.
The data processing was to be done in SAS, which does not have the capability to read
Microsoft Excel (.xls) files. Therefore, the six files were converted into Dbase format
(.dbf), which SAS can import. The first five files were converted to Dbase format
without any alterations to their content, but the structure of the file containing the
cutpoints had to be modified in Excel so that each record (i.e., line of data) in the file
contained short test cutpoints for a single combination of vehicle type, model year group,
and inertia weight class. The resulting file was then saved in Dbase format.
All six files were imported into SAS and merged to form one dataset. The five files that
contain the test results and the vehicle description information were merged on the basis
of the Vehicle Number and Project fields, the combination of which uniquely identify
each vehicle in the program. The vehicles were grouped according to model year and
vehicle type groups, both of which are based on similarities of certification standards.
Passenger cars and light duty trucks were treated as one vehicle group, and medium duty
vehicles (6000 to 8500 pounds gvw) and heavy duty trucks (over 8500 pounds) comprise
the other two vehicle groups. The 640 vehicles for which vehicle information was
supplied are listed in Table 1. Over 75 percent of the vehicles (488 of 640) are 1983 and
later passenger cars and light trucks.
The short test cutpoints (i.e., the cutpoints for 1M240, ASM 5015, and ASM 2525 tests)
were merged onto each vehicle record by means of matching the vehicle model year,
vehicle type, and vehicle inertia weight (rounded down to the nearest 100 pounds) to the
-3-
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TABLE 1
DATA SET BY VEHICLE TYPE
AS RECEIVED
MODEL YEAR
GROUP
PASSENGER
CARS & LIGHT
DUTY TRUCKS
MEDIUM
DUTY
VEHICLES
HEAVY
DUTY
TRUCKS
TOTAL
Pre-1975
43
2
0
45
1975-76
12
2
0
14
1977-79
41
5
0
46
1980-82
42
0
0
42
1983-87
228
0
1
229
1988+
260
0
4
264
TOTAL
626
9
5
640
-4-
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appropriate short test cutpoint. As part of its data preparation, the ARB had appended
to each record the FTP standards to which the vehicles were certified. Short test
cutpoints for each of the three short tests are provided in Appendix A.
The FTP, 1M240, ASM 5015, and ASM 2525 test results collected from the vehicles “as
received” and prior to any test related repairs are referred to as the baseline test results.
The baseline test results for each vehicle (prior to any cleanup of the dataset) were
compared to the FTP standards and short test cutpoints to determine the FTP and short
test pass/fail rates. These baseline results are shown for passenger cars and light trucks
in Table 2, and for medium duty vehicles and heavy duty vehicles in Table 3. The
results under the “Missing/Invalid” columns indicate that the HC, CO, or NO emissions
for a vehicle were either not included in the dataset or were less than zero. (Apparently,
some very low emissions were recorded as less than zero due to improper zero point
calibrations of the test benches used to measure emissions during the short tests.)
3. DATA CLEANUP
As illustrated above, some of the baseline data were invalid and needed to be corrected
or removed. Given the short time period in which the analysis was to be completed, it
was not deemed practical to try to collect new test data to replace missing data or to
redefine or reinterpret negative values, so these data points were eliminated from the
analysis. Consequently, since the purpose of this study is to compare short test results
with FTP results, if one or more short test results were incomplete or invalid, the vehicle
was removed from the analysis dataset.
This phase of the analysis focused on 1980 and later vehicles with three way catalysts,
which effectively eliminated all medium duty vehicles (all were pre-1980) and all heavy
duty vehicles (none had FTP test results). Upon examination of the baseline dataset,
many of the certification standards that ARB had appended to the vehicle data were
.5-
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TABLE 2
FtP AND SHORT ThST RESULTS
FOR PC AND LLYf, AS RECEIVED
MODEL
YEAR
GROUP
FtP
1M240
ASM5O15
ASM2525
MISSING!
INVALID
FAIL
PASS
MISSING!
INVAliD
FAIL
PASS
MiSSiNG!
INVAUI)
FAIL
PASS
MiSSING!
INVALID
PAIL
PASS
Pre-75
N
%
17
39.5
26
60.5
0
-
1
2.3
21
48.8
21
48.8
2
4.7
13
30.2
28
65.1
4
9.3
9
20.9
30
69.8
1975-
1976
N
%
1
8.3
11
91.7
0
-
1
8.3
10
83.3
1
8.3
1
8.3
ii
91.7
0
-
2
16.7
9
75.0
1
8.3
1977-
1979
N
%
4
9.8
37
90.2
0
-
0
-
33
80.5
8
19.5
I
2.4
23
56.1
17
41.5
1
2.4
25
61.0
15
36.6
1980-
1982
N
%
8
19.0
33
78.6
1
2.4
3
7.1
26
61.9
13
31.0
9
21.4
24
57.1
9
21.4
8
19.0
26
61.9
8
19.0
1983-
1987
N
%
65
28.5
157
68.9
6
2.6
8
3.5
118
51.8
02
44.7
18
7.9
111
48.7
99
43.4
0
-
2
40.0
3
60.0
1988+
N
%
156
60.0
68
26.2
36
13.8
4
1.5
23
8.9
33
89.6
64
24.6
25
9.6
71
65.8
50
19.2
25
9.6
.85
71.2
4 , ’
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TABLE 3
FIT AND SHORT ThST RESULTS
FOR MDV AND HDT, AS RECEIVED
MODEL
‘jp
FIT
1M240
ASM5OI5
ASM2525
MISSING!
INVALID
FAIL
PASS
MISSING!
INVAIJ1)
FAIL
PASS
MISSING!
INVALID
FAIL
PASS
MISSINGJ
INVAUD
FAIL
PASS
MDV
Pre-75
N
%
0
-
2
100
0
-
0
-
2
100
0
-
0
-
0
-
2
00
0
-
0
-
2
00
MDV
1975-
1976
N
%
0
-
2
100
0
-
0
-
2
100
0
-
0
-
1
50.0
1
50.0
0
-
2
100
0
-
MDV
1977-
1979
N
%
1
20.0
4
80.0
0
-
1
20.0
2
40.0
2
4.0.0
1
20.0
3
60.0
1
20.0
1
20.0
3
60.0
1
20.0
HDT
1983-
1987
N
%
1
100
0
-
0
-
1
100
0
-
0
-
1
100
0
-
0
-
1
100
0
-
0
-
HDT
1988 +
N
%
4
100
0
-
0
-
4
100
0
-
0
-
4
100
0
-
0
-
4
100
0
-
0
-
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found to be in error. Communications with ARB personnel through Sierra resulted in
ARB providing a dataset with corrected certification standards, and Table 4 lists the FTP
certification standards for the vehicles in the resulting analysis dataset. At this point in
the cleanup process, the dataset included of 242 1980 and later passenger cars and light
trucks that had valid test results for the FTP and all three short tests.
Next, the FTP emissions were regressed against the short test emissions in an effort to
identify any vehicles whose short test emissions would grossly underpredict or overpredict
FTP emissions. Several vehicles were identified as potential outlier vehicles using the
criterion that the absolute value of the residual divided by the standard error of the
residual was greater than 2.0. Further examination of these vehicles revealed that almost
all were high FTP emitters for HC and CO, but were capable of passing a short test (i.e.,
they were likely to be “errors of omission”). It was decided that these vehicles should be
retained in the analysis data set, since high cold start emissions.
Of greater concern was identifying those vehicles which had abnormally high emissions
on only of the short tests, which indicated that some transient malfunction had
occurred during that test only. Such vehicles were likely to be short test false failures, or
“errors of commission.” Twenty-nine 1980 and later vehicles were found to have passed
two short tests and failed one short test. The individual test results for each of these
vehicles were then examined, and it was found that the majority had failed for one
pollutant by a small percentage (less than 20 percent) of the short test cutpoint, or that
they were moderate to high FTP emitters for one or more pollutants that had (correctly)
failed one short test for the same pollutant.
Three vehicles (numbers 44, 117, and 294) were normal FTP emitters that had failed
only one short test by 35 percent of the short test cutpoint or more. These vehicles were
likely to have transient malfunctions that may not result in the vehicle failing a “second
-8-
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TABLE 4
FTP STANDARDS, g/mile
PC & LOT, AS RECEiVED
MODEL YEAR
FUEL FEED
HC/CO/ NO 1
N
PERCENT
1980-1982
1980-1982
1980-1982
MPI
MPI
MPI
0.39/ 7/ 0.7
0.41/ 7/ 0.7
0.41/ 9/ 1
1
2
2
0.4
0.8
0.8
1980-1982
1980-1982
1980-1982
1980-1982
1980-1982
Carb
Carl,
Carb
Carb
Carb
0.5/ 9/1.5
039/ 7/ 0.7
0.39/ 9/ 1
0.41/ 7/ 0.7
0.41/ 9/ 1
1
3
1
4
2
0.4
1.2
0.4
1.7
1.8
1980-1982
1980-1982
TB!
TB!
0.41/ 7/ 0.7
0.41/ 3.4/ 1
1
1
0.4
0.4
1983-1987
1983-1987
1983-1987
1983-1987
1983-1987
1983-1987
1983-1987
MPI
MPI
MN
MPI
MPI
MPI
MPI
0.5/ 9/ 1
039 7/ 0.4
039 7/ 0.7
039/ 9/ 1
0.41/ 7/ 0.4
0.41/ 7/ 0.7
0.41/ 3.4/ 1
2
1
20
5
1
17
5
0.8
0.4
8.3
2.1
0.4
7.0
2.1
1983-1987
1983-1987
1983-1987
1983-1987
1983-1987
1983-1987
1983-1987
1983-1987
1983-1987
Carb
Carb
Carb
Carb
Carb
Carb
Carb
Carb
Carb
0.5/ 9/ 1
1.7/ 18/2.3
039 7/ 0.4
0.39 7/ 0.7
039 9/ 1
039 9/ 0.7
0.41 7/ 0.7
0.41 9/ 1
0.41 3.4 1
5
1
2
29
17
1
8
3
3
2.1
0.4
0.8
12.0
7.0
0.4
3.3
1.2
1.2
1983-1987
1983-1987
1983-1987
1983-1987
1983-1987
1983-1987
TB!
TB!
TB!
TB!
TB!
TB!
0.39/ 7/ 1
039/ 7/ 0.7
039/ 9/ 1
0.41/ 7/ 1
0.41/ 7/ 0.7
0.41/ 3.4/ 1
1
13
2
1
5
1
0.4
5.4
0.8
0.4
2.1
0.4
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TABLE 4
VI P STANDARDS, g/mile
PC & LDT, AS RECEIVED
(CONTINUED)
MODEL YEAR
FUEL FEED
HC/CO/NOX
N
PERCENT
Post 1987
Post 1987
Post 1987
Post 1987
Post 1987
Post 1987
Post 1987
Post 1987
Post 1987
MN
MPI
MPI
MN
MPI
MN
MN
MPI
MN
0.5/ 9/ 1
0.39/ 7/ 0.4
039/ 7/ 0.7
0.39/ 9/ 1
039/ 9/ 0.4
0.41/ 7/ 0.4
0.41/ 7/ 0.7
0.41/ 9/ 0.4
0.41/ 3.4/ 1
8
19
5
4
4
1
1
1
3
3.3
7.9
2.1
1.7
1.7
0.4
0.4
0.4
1.2
Post 1987
Post 1987
Post 1987
Post 1987
Post 1987
Carb
Carb
Carb
Carb
Carb
039/ 7/ 0.4
0.39/ 7/ 0.7
039/ 9/ 1
0.41/ 7/ 0.4
0.41/ 7/ 0.7
1
3
1
1
3
0.4
1.2
0.4
0.4
1.2
Post 1987
Post 1987
Post 1987
Post 1987
Post 1987
Post 1987
Post 1987
TB!
TB!
TB!
TB!
TB!
TB!
TB!
0.5/ 9/ 1
039/ 7/ 0.4
0.39/ 7/ 0.7
039/ 9/ 1
0.41/ 7/ 0.4
0.41/ 7/ 0.7
0.41/ 3.4/ 1
7
6
4
2
1
3
3
2.9
2 . 5
1.7
0.8
0.4
1.2
1.2
-10-
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chance” test, and therefore, would not be good candidates for including in an analysis of
repair effectiveness. Therefore, these three vehicles were classified as “outliers”.
A fourth vehicle also failed only one short test by a significant amount: Vehicle 88
failed the ASM 2525 CO test by 85 percent of the standard. Although this vehicle was a
high FTP emitter, it was also classified as an “outlier” on the basis of its relatively low
test scores on the 1M240 and ASM 5015 test. Table 5 lists the four vehicles that were
classified as outliers.
4. ANALYSIS DATASET
After the four outlier vehicles were removed, the dataset consisted only of vehicles with
HC, CO, and NO test results for all four test types. At this point, certain model year
groups were combined so that there would be sufficient vehicles in those groups to
produce significant results Thus, 1980 to 1982 MPI and TB! vehicles were combined
with the 1983 to 1987 Ml ’! and TB! groups, respectively, and all carbureted vehicles were
combined into one group.
Two additional vehicles were removed from the analysis dataset because their
certification standards were significantly different from the other vehicles in the dataset.
One vehicle had certification standards of 0.5 g/mi HC, 9.0 g/mi CO, and 1.5 g/mile
NOR, and the other had certification standards of 1.7 HC/18 CO/2.3 NOr
Finally, any vehicles that were certified to a nonmethane hydrocarbon (NMHC) standard
of 039 g/mile were grouped with those vehicles that were certified to a 0.41 g/mi total
hydrocarbon standard. Table 6, then, lists the certification standards of the 236 1980 and
later vehicles in the analysis dataset, grouped by model year and fuel delivery system
(“fuel feed”). The table shows that only 74 of the 236 vehicles (31 percent) with a
complete set of test results are 1988 and later fuel injected vehicles. Further, only 48
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TABLE 5
OUTLIER VEHICLES WITH POTENTIAL TRANSIENT
MECHANICAL FEATURES
VEHICLE
NUMBER
MODEL YEAR
GROUP
FUEL
SYSTEM
REASON FOR CLASSIFICATION
294
1983-1987
Carb
Normal FTP HC and N0 , moderate FTP CO.
Failed ASM NO only; 35% over cutpoint.
44
1988
MPI
Normal FTP HC, CO and NOr Failed ASM
25/25 NO only; 65% over cutpoint.
117
1988
Carb
Normal FTP HC, CO, and NOR. Failed MM
25/25 HC and CO; CO was 10 times cutpoint.
88
1983-1987
MPI
.
Moderate FTP HC and NOR, high FTP CO.
Failed ASM 25/25 CO only; 85% over cutpoint.
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TABLE 6
FF1’ STANDARDS, g/mile
PC & LDT, AFFER CLEAN UP
MODEL YEAR
FUEL FEED
HC/COf NO 1
N
PERCENT
1980-1987
1980-1987
1980-1987
1980-1987
MPI
MP!
MP!
MP!
oil 9/ 1
0.41/ 7/ 0.7
0.41/ 9/ 1
0.41 3.4/ 1
2
39
7
5
0.8
16.5
3.0
2.1
Post 1980
Post 1980
Post 1980
Post 1980
Post 1980
Post 1980
Cart,
Carb
Carb
Carb
Caxb
Carb
0.5/ 9/ 1
0.41/ 7/ 0.4
0.41/ 7/ 0.7
0.41/ 9/ 1
0.41/ 9/ 0.7
0.41/ 3.4/ 1
5
4
47
24
1
3
2.1
1.7
19.9
10.2
0.4
1.3
1980-1987
1980-1987
1980-1987
1980-1987
TB!
TB!
TB!
TB!
0.41/ 7/ 1
0.41/ 7/ 0.7
0.41/ 9/ 1
0.41/ 3.4/ 1
2
19
2
2
0.8
8.1
0.8
0.8
Post 1987
Post 1987
Post 1987
Post 1987
Post 1987
Post 1987
MP!
M l ’!
M I’!
Ml’!
M l ’!
Ml’!
0.5/ 9/ 1
0.41/ 7/ 0.4
0.41/ 7/ 0.7
0.41/ 9/ 1
0.41/ 9/ 0.4
0.41/ 3.4/ 1
8
22
6
4
5
3
3.4
9.3
2.5
1.7
2.1
1.3
Post 1987
Post 1987
Post 1987
Post 1987
Post 1987
TEl
TB!
TB!
TB!
TB!
0.5/ 9/ 1
0.41/ 7/ 0.4
0.41/ 7/ 0.7
0.41/ 9/ 1
0.41/ 3.4/1
7
7
7
2
3
3.0
3.0
3.0
0.8
13
-13-
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vehicles (20 percent of the analysis dataset) are 1988 or later niultipoint fuel injected
vehicles.
5. ANALYSIS OF DATA
The ARB sample of vehicles that were subject to FTP testing what primarily those that
failed either the ASM tests or the 1M240 test. Hence the sample is heavily biased
towards high emitters making it relatively difficult to evaluate the error of commission
rate with any degree of statistical precision.
Initially, EEA has hoped to separate at the 1980-82 vehicles as a group due to the fact
that they represent first generation closed-loop control technology. Unfortunately the
total sample of 1980-82 vehicles with FTP tests was 17 vehicles, almost all of which were
high emitters. As a result, 1980-1987 vehicles were treated as one group, and 1988+
vehicles as a second group (except for a few carburetted 1988 + that were combined with
the 1980-1987 group). This sample was divided into normal moderate, and high emitters
using the actual certification standards and moderate emitter cutpoints as defined below:
Pollutant
Certification Std
Moderate Emitter
Cutpoint
HC
0.41
0.50 (LDT)
0.82
0.82
CO
3.4
7.0
9.0
10.5
10.5
13.5
NO
1.0 (LDT)
1.0 (PC)
0.7 (PC)
0.4
2.0
1.4
1.4
0.8
Based on these parameters the available sample of cars was divided into normal,
moderate, and high emitters, classified on the basis of the highest emission level relative
-14-
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to the standard for any pollutant. Table 7 shows the distribution of the sample among
the three emitter categories, by fuel system type. As can be seen, there are only 31
normal emitters in the sample, and 21 of these are in the 1988 + MPI group. Hence, the
error of commission analysis is subject to large statistical uncertainty. The sample under
the alternative moderate emitter cutpoints is larger, but still very small for some groups.
The tests were rated in three bases:
• Failure rates
• Excess Emissions Identified
Errors of Commission
Both error of commission and excess emission identification rates were calculated at
normal and moderate cutpoints. Cutpoints used for the short test varied HC, CO and
NO,, cutpoints specified in Appendix A by + 20, -20 and -40 percent for each pollutant.
Analysis was performed only the same level of reduction (or increase) in HC, CO and
NO,, cutpoints, and no attempt was made to optimize each cutpoint separately due to
resource constraints. The cutpoints in Appendix A are labelled as “C’, while the others
are labelled as C + 20, C-20, and C-40, respectively.
Failure Rates
The analysis of failure rates is presented first. In this case, the unique sample content
should be recognized for its bias towards high emitters so that conventional numbers in
the range of 20 to 30 percent cannot be expected. One measure of an “ideal” failure rate
is a rate representing the fraction of high emitters in the sample. If there were no errors
of commission, a failure rate equal to the ideal failure rate would be optimal.
Table 8 shows the “ideal” failure rates and at the four alternative cutpoints for the
1M240, ASM 5015 and ASM 2525 tests. Since each car can only pass or fail the test, the
standard error of the failure rate estimate is (p • f/n) ° where f is the failure rate, p
-15-
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TABLE 7
SAMPLE BY EMITThR CAThGORY
MYR Group Fuel System Normal Moderate I-Ugh Total
1980-87 MN 5 7 41 53
(9.43) (13.21) (77.36)
1988+ MN 21 14 13 48
(43.75) (29.17) (27.08)
1980-87 TB! 1 1 23 25
(4.0) (4.0) (92.0)
1988+ TB! 3 12 11 26
(11.54) (46.18) (42.31)
1980÷ CARB 1 12 71 84
(1.19) (14.29) (84.52)
TOTAL
Percent of sample in parenthesis; rows add up to 100 percent. High emitters indudes super
emitters.
-------
TABLE 8
FAILURE RATES (Percent of Sample)
Cutpoint Level
Group Test C + 20% - 20% - 40%
1980 - 1987 MPI 1M24() 47.17 64.15 67.92 75.47
(Ideal Rate = 77.36) ASM5O15 47.17 54.72 67.92 75.47
ASM 2525 47.17 56.60 64.15 71.70
1988 + MPI 1M240 8.33 20.83 27.08 37.50
(Ideal rate = 27.08) ASM5 O I5 14.58 20.83 31.25 45.83
ASM2525 12.50 25.00 31.25 33.33
1980 - 1988 TBI 1M240 56.00 72.00 76.00 92.00
(Ideal rate = 92.0) ASM5 O 15 56.00 64.00 76.00 80.00
ASM2525 56.00 72.00 fl.00 84.00
1988 + TB! 1M240 19.23 26.92 34.62 42.31
(Ideal rate = 42.31) ASM5 O 15 38.46 46.15 46.15 50.00
ASM2525 23.08 30.77 38.46 57.69
(All) CARB 1M240 58.33 69.05 fl.62 88.10
(Ideal rate = 84.52) ASM5 O I5 63.09 72.62 78.57 83.33
ASM2525 61.90 fl.62 80.95 86.90
Statistically different rate from other short tests rates at 90% confidence.
-------
the pass rate, and n the sample size. For a sample size of 50 vehicles and p = f = O.5,
the sample standard deviation is 7%. Hence, failure rates for the MPI samples have a
standard deviation of 6 to 7 percent, the TB! samples have standard deviation of 4 to 10
percent, while the CARB samples have a standard deviation of 4 to 5 percent.
Based on these observations, it can be easily concluded that all three tests show
statistically similar failure rates and the variations in failure rates between tests seen at
some cutpoint levels are associated with vehicles marginally above or below a specific
cutpoint for a given test. Hence, all three tests should provide equivalent failure rates in
the field, unless the error of commission rates are substantially different. However, the
!M240 test appears to provide a slightly higher failure rate for the 1980-1987 vehicles
while the ASM tests provide a slightly higher failure for the 1988 + vehicles.
Excess Emission Identification Rates
Total excess emissions are the emissions in excess of standards summed over all
moderate and high emitters in the sample. Excess emission identification rates also must
account for the unusual composition of the sample with its overweighting of high
emitters. Table 9 shows that a very small fraction of total excess emissions is in the
moderate emitter category for the 1980-1987 vehicles of all fuel system types. Given that
the excess emissions are so heavily associated with the high emitters, it can be expected
that all three tests report very high identification rates. The excess emissions shown in
Table 9 are also indicative of the optimal excess emission identification rates for any
short test.
Excess emissions identification rates are shown in Table 10, arid a clear pattern among
the pre-1988 and 1988 + vehicles is obvious. Direct statistical analysis of excess
This does not vary much with failure rates. For f = 0.75, 5 = 6.1%.
-18-
-------
TABLE 9
PERCENT OF TOTAL EXCESS EMISSIONS
AMONG HIGH EMITr RS IN SAMPLE
HC Co NO _
1980-87 MPI 97.69 98.93 96.28
1988+ MPI 95.05 97.42 83.62
1980-87 TB! 100.00 100.00 97.91
1988+ TB! 88.79 89.84 59.09
CARB (All) 99.60 9929 96.77
-19-
-------
TABLE 10 EXCESS EMISSIONS IDENTIFICATION RATES
HC
CO
NOx
fi
1M240
ASM5O15
ASM2525
E—ASM fi
1M240
ASM5O15
ASM2525
E-ASM fi
1M240
ASM5O15
ASM2525
E—ASM
MPI 80-87 I I
I I
I I
C+20
7853
7328
7131
772111
82.79
7797
8082
81.74 I I
6751
6047
6300
6899
C
90.18
77.16
7874
82.2211
9294
8387
81.74
871511
8214
6599
74.12
77.68
C—20 J
9227
8402
6078
857911
9540
89.71
8265
89.71
84.14
77.08
81.78
85.7
C—40 fl
94.39
8740
6422
8803fl
9644
9250
8677
926911
93.12
91.17
8864
93.42
II
I I
II
MP11988+ II
II
I I
C+20 fi
5091
70.76
45.74
72.97 fi
31.45
64 14
42 17
64.14 fi
50.41
61.06
5771
7335
C
56.59
7666
79 76
94 56 fi
31 45
7021
8723
97.42 fi
71.70
79.03
67.27
84 59
C—20
64.50
9456
6866
94 56
5347
97 42
91 35
97.42
8323
8637
81.79
86 37
C—40 fi
81.45
9499
8866
949911
5954
9742
9135
97.4211
9374
91.16
81.79
91.16
I I
II
I I
TBI8O—87 II
II
II
t ’J
C÷20 fl
C fi
C—20 fi
81.85
88.72
91.65
71.27
7860
8817
7339
7976
8812
820911
916611
91.6611
7690
9157
9250
8284
8593
8974
6970
7864
7884
87911
91711
91.711
82.14
90.11
94.13
7914
8209
94.73
6854
94.70
94.70
8209
94.73
94.73
C—40
96.69
93 99
93.15
96 69
97 28
93 07
84 41
97.28 fi
99 80
94 73
96 80
96 83
II
I I
I I
TB 11988+ I I
I I
I I
C+20
5036
6846
40 90
6846 fi
61 70
6697
5557
66.97 fi
39.76
6301
53.86
63.01
C fi
5484
68,46
6399
6846fl
6697
7130
6697
71.3 I I
4685
6773
5592
6773
C—20 fi
58.09
68 46
63 99
68 46
6697
71 30
71 30
71.3 fi
62 90
67 73
6064
67.73
C—40 fi
68.46
68.50
72 64
72.68 fl
71.90
71 30
74 95
7495 fl
67.73
67 73
7933
79 33
II
II
I I
CARB(ALt.)II
II
II
C+20 fi
93.47
90.83
9072
927311
8999
8645
8784
886211
8066
85.04
8281
8617
C fi
96.20
9395
9545
974511
9395
8934
81.74
91.3 I I
8936
8968
9086
9454
C—20 fi
9825
9566
9669
99.14 I I
9540
9552
9184
973411
9332
90.76
94.27
9617
C—40 I I
99.52
9673
9825
992811
9863
9650
9780
9808fl
9894
9148
9501
97.16
II
II
II
PERCENT OF TOTAL EXCESS ABOVE FTP STANDARD
-------
emissions identification rates is difficult as the variance depends on the underlying
distribution of emissions, which is nQI log-normal due to the biased sample. Hence a
non-parametric ranking test must be used. The ranking of that test is based on excess
emission identification rate at 4 cutpoints by model year/fuel system group and is as
follows for HC/CO:
Ranki Rank2 Rank3
MPI, 1980-87 1M240 (8) ASM5O15 (6) ASM2525 (6)
MPL, 1988+ ASM5OI5 (6) ASM2525 (5) 1M240 (7)
TB!, 1980-87 1M240 (7) ASMSO15 (6) ASM2525 (6)
TB!, 1988+ ASM5O15 (6) ASM2525 (4) 1M240 (5)
CARB (All) 1M240 (8) ASM2525 (5) ASM5O15 (5)
These rankings are based on excess emission identification rates being higher in at least
5 of 8 HC and CO cutpoint combinations relative to the next lower rank test. The
numbers in parenthesis refer to the number of times that particular test had the ranking
under which it is listed. In general the ASM 5015 and 2525 tests are ranked relatively
close together, but it appears that the 1M240 test is superior for pre-1988 vehicles while
the ASM tests are superior for 1988+ vehicles, an unexpected result. The rankings for
NO emission identification rates are very similar except that the ASM5O1S appears
slightly worse than the ASM2525.
Table 11 shows the excess emission identification rates based on the “moderate” cutpoint
(i.e. only high emitters contribute to excess emissions) and the ranking of the tests is
unchanged from the above table, although the 5015 and 2525 tests provide near
equivalent results in more cases. The excess emission identification rate is more
consistent for similar model year groups, than by fuel system type. For the pre-1988
vehicles, the IM 240 test identifies 96 percent of both excess HC and excess CO
emissions (±2 percent), and 94 percent of excess NO emissions at the base California
• 2 first place rankings.
-21-
-------
TABLE 11 EXCESS EMISSiONS IDENTIFICA11ON RATES
I-C Co NOx
MOO STDS fi 1M240 ASM5O15 ASM2525 E—ASM fi tM240 ASM5O15 ASM2525 E-ASM fi 1M240 ASM5O15 ASM2525 E-ASM
— II II
MPI 80-87 II II I I
C+20 fi 88.04 80.45 7814 839711 8683 81 27 8411 84.5711 77.40 6623 72.63 73.71
C 96.48 82.79 84.84 87 18 fi 96.17 86 86 84.57 90.16 I I 8649 8875 82.66 85.18
C—20 fi 97.57 8741 8499 88,27 9790 91 88 8491 91 88 fl 86.49 78.31 8800 90.1
C-40 fi 9845 8852 8633 68.52 I I 9826 9396 8834 10011 9636 9544 9426 9636
I I I I I I
MP11988+ I I I I I I
C+20 I I 6413 8079 5025 60.79 fi 1818 7050 4657 705 fi 7906 8796 7784 9675
C fi 6749 8354 8887 100H 1818 7050 10000 lOOft 8985 9875 8196 9875
C—20 69.87 10000 9725 10011 4657 10000 10000 10011 9461 9875 9875 9875
C —40 fi 7784 10000 97 25 100 fi 4657 10000 10000 100 fl 10000 9875 98.75 9875
II II II
TBI8O—87 II II II
C+20 8981 77.10 78.14 857611 7962 9046 7393 929611 90.61 8493 7209 8543
C 9291 6304 8542 948511 9427 9181 7923 938811 9395 8542 9887 9887
• ( —20 9484 92 13 9206 9485 94,27 92 73 7923 9388 9661 9887 9887 9887
C—40 II 97.53 95.92 9475 975311 9789 9427 9861 978911 10000 9887 96.67 9887
• I I II II
TBI 1988+ II II I I
C+20 6993 8539 5220 853911 7711 7896 6880 789611 8160 8160 8160 816
C fi 6993 85.39 8539 853911 8099 7896 7896 789611 8160 8160 8160 81.6
C—20 fl 69.93 85.39 8539 653911 6099 7896 7896 789611 8160 8160 8160 816
C—40 8539 85.39 8539 853911 8099 7896 7896 789611 8160 8160 10000 100
II II II
GARB (ALL) I I I I II
C+20 9707 9348 9369 947711 9449 8924 9067 909311 8701 8980 87.49 898
C fl 9863 9533 9733 984811 9707 9101 9232 923911 9562 9312 9365 97.61
C—20 fl 9977 9669 97.58 998511 9746 9708 92.48 982811 9761 9312 95.64 9761
C—40 9998 9763 9895 998511 9974 9764 9861 986111 10000 93.11 9584 9761
PERCENT OF TOTAL EXCESS FROM HIGH EMITFERS ONLY
-------
cutpoints, when defining excess emissions on the basis of high emitters only. In contrast
the ASM tests identify about 87 percent of HC and 90 percent of CO for the same group
of vehicles. NO 1 emission identification rates are near equivalent to those for the 1M240
test.
For 1988 + vehicles, the situation reverses, with the ASM tests showing significantly
better results, especially for the vehicles with M l ’! fuel systems. However, the emission
identification rates are significantly lower than those for pre-1988 vehicles.
EEA also examined the failure rates for super emitters, defined as vehicles exceeding
NO 1 standards by a factor of 4, or HC/CO standards by a factor of 10. There are 35
vehicles in the data base that would be classified as super emitters, and more than half
of these are due to their high NO 1 emissions, as shown below:
Number of Super Emitters
Reason for Classification
Fuel System High HC/CO High NO 1
MPI, 1980-87 4 4
MN, 1988+ 0 1
TB!, 1980-87 2 6 (1 with High HC)
TB!, 1988+ 0 1
CARB (All) 9 10(1 with High HC)
Total 22(2 with High HC)
Cars certified to a 0.4 NO 1 standard could be classified as super emitters if their
emissions exceed 1.60/mi for NO 1 . Both 1988+ vehicles classified as super emitters on
the basis of their NO 1 emissions are certified to the 0.4 NO 1 standards, with one at 1.84
g/mi and the other 2.83 g/mi. Two other super emitters are also super NO 1 emitters
relative to the 0.4 standard, one a 1984 M l ’! vehicle at 3.92 g/mi and the other a 1986
-23-
-------
vehicle at 1.74 g/mi. These vehicles would not be classified as super emitters under a I
g/mi NO standard, and only I vehicle would qualify as a super emitter under a 0.7 g/mi
NO standard.
Nevertheless, the IM/240 test fails ll super emitters at California cutpoints. Both ASM
short tests curiously pass one HC/CO super emitter, a carburetted 1985 vehicles with
FTP emissions of 2.54 HC/8 1.42 CO/0.49 NO,,. Each ASM test also passes one super
NO,, emitter; the ASM 5015 passes a 1985 carburetted vehicle at 2.95 g/mi NO while
the ASM 2525 passes the 1986 vehicle at 1.74 g/mi (a car certified to a 0.4 NO,,
standard, described above). Hence, the ASM test super emitter identification rate for
HC/CO super emitters is 93.3 percent, and is 90.9 percent for NO super emitters.
Because of the relatively small sample, these values are not statistically different from
the 100 percent identification rate observed for the I/M 240.
Tables 10 and 11 also shows the excess emission identification rates for the case of
vehicles failing either one of the ASM tests. While this increases the error of
commission rates, it does help the ASM excess emission identification rates for 1980-
1987 vehicles. Although the conclusion regarding ranking for the 1M240 vis-a-vis either-
ASM test are not changed, the combined set of ASM tests are almost equivalent to the
!M240 for the pre-1988 vehicles, and are significantly better than the 1M240 test for the
1988 + vehicles, in terms of excess emissions identification rates.
Errors of Commission
Errors of commission are those vehicles that would fail a short test but pass the FTP.
The ARB has adopted a second definition, to include vehicles failing a short test that are
moderate emitters. Typically, the error of commission rate . using either definition, is the
errors of commission normalized by the total failure rate or by the total sample. Due to
the biased sample in this study, the rate as normally defined is not very mepningful.
-24-
-------
Errors of commission (in absolute number of vehicles) can be defined with some
statistical significance for only vehicles in the 1988 + MPI group, as all other groups
contain five or fewer normal emitters. The 1988+ MPI group contains 21 normal
emitters and the errors of commission at the four different cutpoints are listed below.
1M240 ASM5 O I5 ASM2525
C+20 0 0 0
C 1 0 1
C-20 1 0 2
C-40 2 5 3
Conversion to a error of commission rate will be very misleading since the sample is so
heavily biased towards failing vehicles. In this case of the 1988 + MPI group, 4.76
percent of all FTP normal emitters fail the IM 240 at California cutpoints. The standard
deviation of this rate is ± 4.647; hence it is possible to have a zero sample error of
commission and not be different from the 4.76 percent rate at 90 percent confidence.
The errors of commission for the ASM5O1S and ASM2525 are statistically similar at
C + 20%, C, and C-20%, but the ASM 5015 has a significantly different error of
commission rate at C-40%.
All other groups had five or fewer normal emitters, and the uncertainties surrounding
the sample error of commission rate is very large. Nevertheless, among the entire
sample of 10 normal emitters in all groups other than 1988+ MPI, these was only one
error of commission. This vehicle was an error of commission at all cutpoints expmined
for 1M240 and ASM5O15, but was an error of commission only at the C-40% cutpoint on
the ASM2525 test.
Using the ARB definition of error of commission, it is possible to expmine the number
of errors of commission for all groups except the 1983-87 TBI group which had only 2
-25-
-------
vehicles under the moderate emitter cutpoint. Table 12 lists the errors of commission
using this revised definition.. The 1M240 error of commission rate is almost identical to
the ASM error of emission rates at “C” cutpoints for pre-1988 vehicles, but is higher for
the 1988 + MPI group and lower for the 1988 + TB! group. None of these differences
are statistically significant; across the entire set of 1980+ vehicles, the ASM2525 and
1M240 have similar error of commission rates, whole the ASM5O15 has a slightly higher
rate. At the California cutpoints, the errors of commission divided by the total number
of normal and moderate emitters is 14.3 percent for the 1M240, 15.58 percent for the
ASM5O15, and 1035 percent for the ASM2525.
In order to derive the error of commission rate for an unbiased sample the failure rates
of (normal + moderate) emitters and the failure rate of high emitters must be calculated
separately. Due to the inadequacy of the sample at the model year group/fuel system
level, we have analyzed all 1988 + vehicles together, and these failure rates are listed in
Table 13. An unbiased total sample failure rate can then be used to derive the percent
of high emitters in the unbiased sample. For the IM 240 test, this is done as follows at
the California cutpoint for the short test.
(Normal + Moderate) Emitter Failure Rate 0.1428
High Emitter Failure Rate 0.7295
Unbiased Sample Failure Rate 0.3130
If the percent of high emitters in the unbiased sample is “x”, then
0.7295 x + 0.1428 (1-x) 0313
x 28.98%
-26-
-------
TABLE 12
ERRORS OF COMMISSION (Alternative)
NORMAL + MODERATE EMIT mRS
Group
Cutpoint
1M240
ASM5O15
ASM2525
E-ASM
Ml ’ !, 1983-1987
(N=12)
C + 20
C
C-20
C-40
2
2
3
3
0
2
5
5
2
2
4
5
2
2
5
6
NIP! 1988+
(N=35)
C+20
C
C-20
C-40
0
4
6
7
0
1
3
10
1
2
4
5
1
3
5
12
TB! 1988+
(N=15)
C+20
C
C-20
C-40
1
2
4
5
4
6
6
7
2
2
4
8
4
6
6
9
CARB(A11)
(N=13)
C+20
C
C-20
C-40
1
3
3
6
1
3
4
6
1
2
4
6
1
3
5
9
All 1980+
(N=77)
C+20
C
C-20
C-40
4
11
16
22
5
12
18
28
6
8
16
25
8
14
21
37
E-ASM is failing either ASM.
-27-
-------
TABLE 13
FAILURE RATE BY
EM1imR CATEGORY ACROSS ALL GROUPS
(as percent of sample in category)
Cutpoint IM 240 ASM 5015 ASM 2525
Normal + Moderate Emitters
C + 20 5.19 6.49 7.79
C 14.28 15.58 10.29
C - 20 20.78 2338 20.78
C - 40 28.57 36.36 32.46
High Emitters
C + 20 58.49 65.40 61.00
C 72.95 72.95 76.10
C - 20 7736 81.76 81.13
C - 40 90.56 86.16 86.79
-28-
-------
Hence the error of commission rate is
E = 0.1428 (1-x
0.313
= 32.4% (based on failed vehicles)
or 10% (based on the total sample)
Similarly for the ASM 5015
E = 28.7% (or 10.18% based on total sample)
and for the ASM 2525
E = 29.7% (or 10.15% based on total sample)
These values appear very high, and were re-evaluated at C + 20% cutpoints. Based on
the same set of calculations we can find that for the EM 240.
E = 14.0% (based on failed vehicle)
= 3.4% (based on total sample)
The E based on failure rate is nearly identical for all three tests, because the ASM tests
have higher errors of commission and a higher overall failure rate, so that the ratio of
the two does not vary. Based on the total sample, the E is 4.2% for the ASM 5015, and
5.1% for the ASM 2525. These differences are not statistically significant, but non-
parametric tests show that across all cutpoints the IM 240 does have a lower error of
commission rate than the ASM 5015 that is significant at the 90 percent confidence level.
Conclusions
Analysis of the data provided by ARB from a sample of cars tested on the FTP, 1M240
and ASM 5015/2525 tests allowed comparisons of short test effectiveness. However, the
sample was heavily biased towards high ( FTF ) emitters so that firm conclusions could
not be reached on errors of commission.
-29-
-------
Short tests were rated on the failure rate, excess emission identification rate, and error of
commission rate. The test were examined at the California short test standards as well
as standards 20% percent higher, and 20 and 40 percent lower than those specified by
California. The findings are as follows:
All three short tests demonstrate statistically equivalent failure rates at all
cutpoints examined. However, the 1M240 yields a slightly higher failure
rate on pre-1988 vehicles, while the ASM tests yields a slightly higher
failure rate on 1988 + vehicles. These differences are not statistically
significant, except at isolated cutpoint/test combinations.
• Excess identification rates are also equivalent for all three short tests. A
non-parametric test using short test rankings by excess emissions
identification rates indicates that the 1M240 is better on pre-1988 vehicles,
while the ASM test perform better on 1988+ vehicles.
• Due to the very small sample of normal emitters, no conclusions regarding
errors of commission are possible. If an alternative error rate is defined on
the basis of normal or moderate emitters failing a short test, a pooled
sample of all vehicles shows the 1M240 to have a nearly identical error of
commission rate to the ASM2525, which in turn has a slightly lower rate
than the ASM5O15 at each of the four cutpoints examined. Non-
parametric tests indicate that the latter finding is statistically significant.
• At California cutpoints, the actual error of commission rates appear very
high, using a combined analysis of the unbiased and biased samples. The
error of commission (Er) rate is about 30 percent if calculated as a fraction
of all failures, and 10 percent if calculated as fraction of all cars tested. If
cutpoints are relaxed by 20 percent, than E falls to 24 percent of all failed
vehicles or 3.4 percent of the total. This finding could have a very
significant impact on the actual cutpoints used in any program, and the
resultant excess emission identification rate.
-30-
-------
APPENDIX A
List of Cutpoints
Used By California On
The Short Tests
-------
TABLE A-i
Predicted cutpoiils forl98l andn wermod yearvehIdesat2.5%EC
______ PASSENGER CARS
HYDROCARBONS CARBON MONOXiDE OXIDES OF NITROGEN
INERTIA lM240 ASM5O15 ASM2525 1M240 ASM5O15 ASM2525 1M240 ASM5O15 ASM2525
W&ght (it (g/mI) (ppn,) (ppm) (gJm ) (%) (%) I I (g/mi) (ppm) (ppm) I I
175( 0.97 119.02 11474 23.30 0.67 0.65 II 1.99 1223.99 1105.07 II
200( 0.97 105 64 101 89 23.30 0.59 0.57 II 1.99 1074.99 970.94 II
210( 0.97 101 18 9761 II 23.30 0.57 0.55 II 1.99 1025.32 926.23 II
220( 0.97 97.13 93.72 II 23.30 0.55 0.53 II 1.99 980.17 885.58 I I
230( 0.97 93.42 90.17 II 23.30 0.52 0.51 II 1.99 938.95 848.47 I
240C 0.97 90.03 86.91 II 23.30 0.50 0.49 II 1.99 901.16 814.45 I I
250( 0.97 86.91 83.92 II 23.30 0.49 0.47 II 1.99 866.39 783.15 I
260( 0.97 8403 81.15 II 23.30 0.47 0.45 II 1.99 834.30 754.26 I I
270( 0.97 81.38 7859 II 23.30 0.46 0.44 II 1.99 804.59 72751 I
280( 0.97 78.88 76.21 II 23.30 0.44 0.43 I 1.99 776.99 702.67 I
290( 097 7658 74.00 II 23.30 0.43 0.41 II 1.99 751.30 679.55 1
300( 0.97 74.43 71.93 I 23.30 0.42 0.40 I I 1.99 727.33 657.96 II
310( 0.97 72.41 70.00 23.30 0.40 0.39 I 1.99 704.90 637.77 II
320( 0 97 7052 68.18 I 23.30 0.39 0.38 I 1.99 683.87 618.84 I I
330( 0.97 68.75 66.48 I 23.30 0.38 0.37 II 1.99 664 12 601.05
340( 0.97 67.08 64 88 I I 23.30 0.37 0.36 I I 1.99 645.52 584.32
350C 0.97 65 51 63 37 I I 23.30 0.36 0.35 I I 1.99 62799 56854
360C 0 97 64 02 61 94 I I 23.30 0.36 0.34 I I 1.99 611.44 553 63
370C 0 97 62.62 60 59 I 23.30 0.35 0.34 I I 1.99 595.78 53954 I I
380C 0.97 61.28 59.31 I 23.30 0.34 0.33 II 1.99 580.94 526.18 II
390C 097 60.02 58.10 23.30 0.33 0.32 II 1.99 566.87 513.51 I
4004 0.97 58.82 56.96 23.30 0.33 0.32 I I 1.99 553.50 501.47 II
4104 0.97 57.68 55 85 I 23.30 0.32 0.31 I 1.99 540.78 49002 I I
4204 0.97 56.59 54.81 I 23.30 0.31 0.30 I I 1.99 528.66 479.11
4304 0.97 55.55 53.81 23.30 0.31 0.30 II 1.99 517.11 468.72 I
4404 0.97 54.56 52 86 II 23.30 0.30 0.29 II 1.99 506.09 458.79 II
4504 0.97 5362 51.96 II 23.30 0.30 0.29 1.99 49555 449.31 H
4604 0.97 52.71 51 08 II 23.30 0.29 0.28 1.99 485.47 440.24 II
4704 0.97 51.85 5025 2330 029 0.28 II 1.99 47583 431.55 II
4804 0.97 51.02 49.46 II 2330 0.28 027 II 1.99 466.58 42323 I
4904 0.97 5022 48.69 23.30 028 0.27 II 1.99 457.71 415.24 II
5004 0.97 49.46 47.96 II 23.30 0.27 0.26 II 1.99 449.20 407.58 II
5254 0.97 47.67 46.25 II 23.30 0.26 0.26 II 1.99 429.33 389.69 I
5504 0.97 46.05 4469 I I 23.30 0.25 0.25 I I 1.99 411.27 373 43 I I
6004 0.97 43.21 41.96 II 23.30 0.24 0.23 II 1.99 379.66 344.98 I I
6504 0.97 40.81 39.66 I I 23.30 0.22 0.22 I 1.99 352.92 32090 I
7004 0 97 38.75 37.68 I 23 30 0.21 0.21 1.99 330.00 30027 II
Page A-I
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TABLE A-i
rec cte cutp for 1975-1960 rno iei y veI es at 2.5% EC
_____ PASSENGER CARS
HYDROCARBONS CARBON MONOXIDE OXIDES OF NITROGEN
INERTIA 1M240 ASMSO15 ASM2525 1M240 ASM5O15 ASM2525 1M240 ASM5O15 ASM2525
Weight (II (g/mi) (ppm) (ppm) (gJmI) (%) (%) I (g/mi) (ppm) (ppm) I I
1754 1.45 172.09 158.21 20.27 0.92 0.61 I I 5.13 4100.95 4278.62
200( 1.45 152.08 139.93 20.27 0.82 0.54 II 5.13 3588.33 3743.79
210( 1.45 145.41 133.84 20.27 0.78 0.52 I I 5.13 341746 3565.52
220( 1.45 139.35 128.30 20.27 0.75 0.50 II 5.13 3262.12 3403.45 II
230C 1.45 133.81 123.25 20.27 0.72 0.48 II 5.13 3120.29 3255.47 II
240( 1.45 128.74 118.61 20.27 0.69 0.46 II 5.13 2990.27 3119.83 II
25 X 1.45 124.07 11435 20.27 0.66 0.45 II 5.13 2870.66 2995.03 II
260( 1.45 119.76 11041 20.27 0.64 0.43 II 5.13 2760.25 2879.84 I
27 X 1.45 115.76 106.76 20.27 0.62 0.42 II 5.13 2658.02 2773.18 II
280( 1 45 112.06 103.38 20.27 0.60 0.40 I I 5.13 2563.09 2674.14
290( 1.45 108.61 100 23 2027 0.58 0.39 II 5.13 2474.71 2581 93 II
300( 1.45 105.39 9729 20.27 0.56 0.38 I 5.13 2392.22 249586 II
310( 1.45 102.38 94 54 2027 0.55 0.37 I 5.13 2315.05 2415.35
320( 1.45 9955 91.96 2027 0.53 0.36 II 5.13 2242.70 233987 H
330( 1.45 96.90 89.53 20.27 0.52 0.35 II 5.13 2174 74 2268.97 II
340( 1 45 94.40 8725 20.27 0.50 0.34 II 5.13 2110.78 2202.23 II
350( 1.45 92.05 85.10 20.27 0.49 034 II 5.13 2050.47 2139.31 II
360( 1.45 89.82 83.07 2027 0.48 0.33 II 5.13 199352 2079.88
370( 1.45 87.72 81.15 2027 0.47 0.32 I 5.13 1939.64 2023.67 II
380( 1.45 85.73 79.33 20.27 0.46 0.31 I I 5.13 1888.59 1970.42 I
390( 1.45 83.84 77 61 20.27 0.45 0.31 5.13 1840.17 1919 89
400( 1.45 82.04 75.97 20.27 0.44 0.30 I 5 13 1794.16 1871.90 II
410( 1.45 80.33 74.41 20.27 0.43 0.30 II 5 13 1750.40 1826.24 II
420C 1.45 78.71 72.92 20.27 0.42 0.29 5 13 1708.73 1782 76 II
43(X 1.45 77.15 71.50 20.27 041 0.28 I I 5.13 1668.99 1741.30 II
440C 1.45 75.67 70.15 20.27 0.40 0.28 5.13 1631.06 1701.72 II
45 X 1.45 74.26 68.86 2027 0.40 0.27 I 5 13 1594.81 1663 91 II
46(X 1.45 72.91 6762 20.27 0.39 0.27 I 5.13 1560.14 162774 1
470( 1.45 71 61 6644 20.27 0.38 0.27 I I 5 13 1526.95 1593 10 I
48 X 1.45 70.37 65.30 20.27 0.38 0.26 II 5.13 1495 14 1559.91 II
490C 1.45 69.18 64.22 20.27 0.37 0.26 I I 5.13 1464.62 1528.08 I
500( 1.45 68.03 63.17 2027 0.36 0.25 I I 5.13 1435.33 149752 I
525( 1.45 65.36 60.74 20.27 0.35 0.24 I 5.13 1366.98 1426.21 II
550( 1.45 62.94 58.52 2027 0.33 0.24 I I 5.13 1304.85 1361.38 II
600( 1.45 58.69 5464 2027 0.31 0.22 II 5.13 1196.11 1247.93 II
650( 1.45 55.10 51.36 20.27 0.29 0.21 I 5.13 1104.10 1151.94 II
700C 1.45 52.02 48.55 20.27 028 20lI 5.13 1025.24 1069.66 11
PageA-2
-------
TABLE A-i
Predicted cLdpokll for 1974 an4 esiller mod year vehides at 2 5% EC
PASSENGER CARS
ii 65.63
II 65.63
H 65.63
II 65.63
II 65.63
II 65.63
H 65.83
II 65.63
II 66.63
II 86.63
II 6563
I! 65.63
H 65.63
II 65.63
II 65.63
II 65.63
II 65.63
II 65.63
II 65.63
II 65.63
II 85.63
II 65.63
II 65.63
II 65.63
II 65.63
II 65.63
H 65.63
II 65.63
65.63
H 65.63
H 65.63
H 65.63
H 65.63
II 65.63
II 65.63
H 65.63
H 6563
4.26
3.75
3.58
3.42
3.28
3.15
3.03
2.92
2.81
2.72
2.63
2.55
2.47
2.40
2.33
2.27
2.21
2 15
2.09
2.04
1.99
1.95
1.90
1.86
1.82
1.79
1 75
1.71
1.68
1.65
1.62
1.59
1.52
1.46
1.35
1.26
1.18
OXI
1 1 .4240
I (a/mi)
DES OF NITROGEN
ASM5O15 ASM2525
(porn) (oom I I
6.11
j
5.67
536726
4998.40
II
5.37
I
5.67
4696.36
4373.60
I I
5.12
5.67
4472.72
4165.33
I
4.89
5.67
4269.41
3976.00
I I
4.69
I
5.67
4083.79
3803.13
II
4.50
I
5.67
3913.63
3644.67
II
4.32
I
5.67
3757.08
3498.88
I I
4.16
I
5.67
3612.58
3384 31
4.01
I
5.67
3478.78
3239.70
I
3.88
5.67
3354.54
3124.00
II
3.75
I
5.67
3238.87
3016.28
II
3.63
I
5.67
3130.90
2915.73
II
3.52
I
5.67
3029.91
2821 68
I I
3.41
I
5.67
2935 22
2733.50
I I
3.31
j
5.67
2846.28
2650 67
I I
3.22
I
5 67
2762.56
2572.71
I I
3.13
I
567
2683.63
249920
1
3.05
I
5.67
2609.09
2429.78
I I
2.97
I
567
253857
236411
II
2.90
I
5.67
2471.77
2301.89
I
2.83
I
5.67
2408.39
2242.87
2.76
I
5.67
2348 18
2186.80
I
2.69
I
5 67
2290.91
2133.46
I I
2.63
5.67
2236.36
2082.67
I I
2.58
I
5.67
2184.35
2034 23
II
2.52
I
5.67
2134.71
1988.00
I I
2.47
I
5.67
208727
1943.82
I
2.42
5.67
2041.89
1901.57
II
2.37
I
5.67
1998.45
1861.11
II
2.32
5.67
1956.81
1822 33
I I
2.28
I
5.67
1916.88
1785.14
I I
2.24
I
5.67
1878.54
1749.44
I I
2.14
I
5.67
1789.09
1666.13
II
2.05
5.67
1707.77
1590.40
II
1.89
5.67
1565.45
1457.87
II
1.76
I
567
1445.03
1345.72
II
1.64
I
5.67
1341.82
124960
II
1M240
CARBON MONOXIDE
ASM5O1 5 A5M2525 1M240 ASM5O1 5 ASM2525
5.83
5.83
5.83
5.83
5.83
5.83
5.83
5.83
5.83
5.83
5.83
583
5.83
5.83
583
5.83
5.83
5.83
5.83
583
583
5.83
5.83
583
583
583
5.83
5.83
5.83
5.83
5.83
5.83
5.83
5.83
5.83
5.83
521.07
496.83
474.79
454.67
436.23
419.26
403.59
389.09
375.62
363.08
35138
34043
330.17
320.53
311.45
302.90
29482
287.17
279.93
273.06
266.54
260.33
254.41
248.78
243.40
238.25
233.34
228.63
224.11
219.78
215.63
205.93
197.12
181.69
168.64
15745
512.02
488.21
466.57
446.80
428.88
412.02
396.63
382.39
369.16
356.84
345.35
33459
324 51
315.04
306.13
297.73
289.79
282.28
275.17
268.42
262.01
255.91
250.11
244.57
239.28
234.23
229.40
224.78
220.34
216.09
212.01
202.48
193.83
178.67
165.85
154.86
Page A-3
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TABLE A-i
Predicted cutpolr*s for 1980 and ee er model year veh des at 2.5% EC
MEDIUM DUTY’ VEHICLES
HYDROCARBONS CARBON MONOXIDE OXIDES OF NITROGEN
INERTiA 1M240 ASM5OI5 ASM2525 1M240 ASM5OI5 ASM2525 1M240 ASM5O15 ASM2525
Weight ( (g/mI) (ppm) (ppm) I I (gJmI) (%) (%) I (g/ml) (ppm) (ppm) I I
490€ 5.83 219.78 216.09 II 65.63 1.62 2.28 j 5.67 1916.88 1785.14 II
500€ 5.83 215.63 212.01 II 65.63 1.59 2.24 I 5.67 1878.54 174944 I
5 10C 5.83 211.64 208.09 II 6563 1.56 2.20 5.67 1841.71 1715 14 II
520€ 5.83 207.80 204.32 II 65.63 1.53 2.16 I 5.67 1806.29 1682.15 I
530€ 5.83 204.10 200.69 I 65.63 1.51 2.12 I 5.67 1772.21 1650.42 II
540€ 5.83 200.54 197.19 II 65.83 1.48 2.08 I 5.67 1739.39 1619.85 II
550€ 5.83 197.12 193.83 I 66.63 1.46 2.05 I 5.67 170777 1590.40 II
560€ 5.83 193.81 190.58 II 65.63 1.43 2.01 I 5.67 1677.27 1562.00 II
570€ 5.83 190. 187.45 II 65.63 1.41 1.98 I 5.67 1647.84 1534.60 II
580€ 5.83 187.54 184.42 II 66.63 1.39 1.95 I 5.67 1619.43 1508.14 II
590€ 5.83 184.57 181.50 II 6563 1.37 1.92 I 5.67 1591.99 1482.58 H
600€ 5.83 181.69 17867 II 65.63 1.35 1.89 I 5.67 1565.45 1457.87 I I
810€ 5.83 178.91 175.94 I 65.63 1.33 1.86 I 5.67 1539.79 1433 97 II
620€ 5.83 176.22 173.30 II 65.63 1.31 1.83 I 5.67 1514.95 1410.84
630€ 5.83 173.61 170.74 II 65.63 1.29 181 I 5.67 1490.91 138844 1
640€ 5.83 171.08 16826 II 65.63 1.27 1.78 I 5.67 1467.61 1366.75 II
650€ 5.83 168.64 165.85 II 65.63 126 1.76 567 1445.03 1345.72 II
660€ 5.83 166.26 163.52 II 65.63 1.24 1.73 I 5.67 1423.14 1325 33 II
670€ 5.83 163.96 161.26 II 6563 1 22 1.71 5.67 1401.90 1305 55 II
680€ 5.83 161.73 159.07 I j 65.63 1.21 1.68 I 5.67 1381.28 128635
690€ 5.83 159.56 156 93 I I 65.63 1.19 1 66 5 67 1361 26 1267 71 II
700€ 5.83 157 45 154.86 II 65.63 1.18 1.64 I 5.67 1341.82 1249.60 I
710€ 5.83 155.40 152.85 65.63 1.16 1.62 I 5.67 1322.92 1232.00 I
720€ 5.83 153.41 150.89 II 65.63 1.15 1.60 5.67 1304.54 1214.89 I
730€ 5.83 151.47 148.99 65.63 1.14 1.58 I 5.67 1286.67 1198.25 II
740€ 5.83 149.59 14714 II 65.63 1.12 1.56 I 5.67 1269.29 1182.05 II
750€ 5.83 147.75 145.34 I 65.63 1.11 1.54 I 567 1252.36 1166.29 II
760€ 5.83 145.97 143.58 II 6563 1.10 1.52 I 567 1235.88 1150.95 II
770€ 583 144.23 141.88 II 65.63 1.08 1.51 I 567 1219.83 1136.00
780€ 5.83 142.53 140.21 II 6563 1.07 1.49 I 567 120419 1121.44 I
790C 5.83 140.88 138.59 II 65.63 1.06 1.47 I 5.67 1188.95 1107.24 II
800€ 5.83 139.27 137.01 II 65.63 1.05 1.45 5.67 1174.09 1093.40 I
810€ 5.83 137.70 135.46 H 65.63 1.04 1.44 I 5.67 115959 1079.90 II
820€ 5.83 136.16 133.96 II 65.63 1.03 1.42 I 5.67 1145.45 1066.73 II
830€ 5.83 134.87 132.49 I 65.63 1.02 1.41 I 5.67 1131.65 1053.88 I
840€ 5.83 133.21 131.05 II 65.63 1 01 1.39 I 5.67 1118.18 1041.33 II
850€ 583 131.78 129.65 II 65.63 1.00 1.38 I 5.67 110502 102908 II
PageA-4
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