United States Air and Radiation EPA420-P-99-021
Environmental Protection May 1999
Agency M6.EXH.010
vvEPA Comparison of MOBILE6
Basic Emission Rates for
1981-1993 Model Year
Cars and Light-Duty
Trucks with FTP and
IM240 Data
DRAFT
> Printed on Recycled Paper
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EPA420-P-99-021
May 1999
of for
FTP
May
DRAFT
Phil Enns
Assessment and Modeling Division
Office of Mobile Sources
U.S. Environmental Protection Agency
NOTICE
This technical, report does not necessarily represent final EPA decisions or positions.
It is 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.
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- Draft -
Comparison of MOBILE6 Basic Emission Rates
for 1981-1993 Model Year Cars and Light-Duty Trucks
with FTP and IM240 Data
Report Number M6.EXH.010
April 1999
Phil Enns
U.S. EPA Assessment and Modeling Division
1.0 INTRODUCTION
The MOBILE6 emissions inventory model will compute basic start and running
emission rates (BERs) as a function of a vehicle's accumulated mileage. The equations
proposed for use in these calculations were developed from Federal Test Procedure (FTP)
and EVI240 data, as described in a series of reports on in-use deterioration. This paper
discusses analyses comparing FTP BER values from MOBILE6 (derived by a combined
weighting of the start and running BERs) with FTP emission levels found in actual data. The
purpose of this work is to obtain a measure of how well BER estimates from the model
replicate real-world emissions.
Two types of comparison are presented. The first is a graphical display of average
FTP emissions found in actual FTP data contrasted with MOBILE6 estimates of FTP
emissions at the same vehicle mileage. This is intended to show in condensed form how well
the MOBILE6 equations represent emissions found in real-world driving. In the second
comparison, data from the Colorado inspection and maintenance (I/M) program are
substituted for the Ohio program data used in MOBILE6 in order to measure the sensitivity
of the model to state-specific characteristics.
The next section reviews the data sources used in these analyses. Section 3 describes
how the comparisons were performed. Section 4 discusses conclusions drawn from the
study.
2.0 DATA Sources
2.1 FTP Data
Since MOBILE6 can produce estimates of FTP emissions, it was decided to compare
these estimates to available raw FTP data. Three sources of data were employed for these
comparisons.
M6.EXH.010 DRAFT 4/30/99
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1. The California Surveillance program is an ongoing effort in that state to monitor its
emission control activities. This program attempts to sample the population randomly
to obtain a representative picture of the fleet. A sample of 559 FTP tests from the
California program was obtained for use in this analysis.
2. Another source of FTP data is the 668 tests conducted on vehicles selected by EPA
in Hammond, Indiana. The vehicles in this sample were recruited from I/M lanes as
part of a program designed to establish the correlation between the IM240 and FTP
tests. Because they were intentionally selected to over-represent high emitting vehicles,
in the current analysis the Hammond data are reweighted so as to more accurately
represent the I/M pass and fail rates in the population of vehicles.1 This reweighting
scheme involved deleting some observations and duplicating others, which resulted in
a final sample of 998 observations.
The Hammond data are employed in MOBILE6 as part of an adjustment to the
in-use deterioration equations that are fitted to the EPA/AAMA/API data. Due to
concerns about possible sample bias in the FTP data of (1) above, the running emission
functions in the MOBILE6 model were adjusted using IM240 data from Dayton,
Ohio2. The Hammond data were used in this process to transform the Ohio IM240
measurements into estimates of running emissions. Thus, the Hammond data set
considered in the analysis of this report played an indirect part in the development of
the MOBILE6 BERs. Note that bias adjustment relied also on 270 IM240 and FTP
tests on vehicles sampled in Phoenix, Arizona. These values were not used in this
analysis because they were not included in the reweighting applied to the Hammond
data.
3. The largest set of FTP data comes from tests conducted by EPA and industry. This
set is referred to here as the EPA/AAMA/API data for the three organizations that
sponsored these tests. These data also were used to develop estimates of running
emissions versus mileage3 and start emissions versus mileage4 in MOBILE6. The API
'Heirigs, P. and L.Caretto, "Data to be Used for CALIMFAC Model," memo to California
Air Resources Board, March, 1994.
2Enns, P., E. Glover, P. Carey, and M. Sklar, "Analysis of Emissions Deterioration
Using Ohio and Wisconsin IM240 Data," Report No. M6.EXH.002, October 1998.
3Enns, P., E. Glover, P. Carey, and M. Sklar, "Determination of Running Emissions
as a Function of Mileage for 1981-1993 Model Year Light-Duty Cars," Report No.
M6.EXH.001, October 1998.
4Glover, E. and P. Carey, "Determination of Start Emissions as a Function of Mileage
and Soak Time for 1981-1993 Model Year Light-Duty Vehicles," Report No. M6.STE.003,
M6.EXH.010 -2- DRAFT 4/30/99
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sample of 103 vehicles intentionally includes vehicles with high mileage
accumulation. The EPA vehicles, tested over a number of years, show comparatively
lower mileages. The AAMA data were collected only for 1990-93 vehicles with lower
mileages also. All these samples were obtained through voluntary response to
solicitations for test participation. This gives rise to concerns about their
representativeness which were addressed in MOBILE6 by the use of an adjustment
based on EVI240 data.
Table 1 provides summary statistics for each of the three FTP data sets. The data are
classified into the categories of vehicle type, fuel metering and model year group defined in
MOBILE6. In the model, functions of emissions deterioration are fitted for each of these
categories.
Using the EPA/AAMA/API and Hammond data in the construction of MOBILE6
casts suspicion on their use in validating the model. With the former, it is perhaps best to
view the exercise as simply confirming that the model is indeed based on these data. But the
path from the data to the final model equations is not entirely straightforward, especially in
light of the bias adjustment step. With the Hammond data the relation between the model
and the data is much less obvious, making these values more like a truly independent set of
observations.
2.1 IM 240 Data
In addition to direct FTP comparisons, this report considers the impact of the EVI240
bias-adjustment in terms of the state source of I/M data. EPA acquired a sample of
approximately 1.2 million tests conducted in Colorado in 1995 and 1996. As described in
Section 3.2, these data were substituted for the Ohio data in the adjustment phase of the
development of MOBILE6 BER functions. The distribution of model year, vehicle type and
technology for both the Colorado and Ohio EVI240 data is given in Table 2.
3.0 COMPARISONS TO MOBILE6
3.1 FTP Data
In order to compare the MOBILE6 estimates with FTP data, it is necessary to
combine the start and running estimates to compute composite FTP emissions. For this
analysis the following equation is used:
FTP=(7.5*Running + .521* Start)/?. 5
which yields a value in units of grams per mile.
October, 1998.
M6.EXH.010 -3- DRAFT 4/30/99
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A variety of comparisons are possible between the FTP data and the MOBILE6 BER
estimates. In the approach used here, a regression equation was estimated for each pollutant,
data source, and model year-technology category. For example, in the category of 1988-93
TBI cars, the California surveillance sample contains 32 tests. Within this sample, both
emissions and vehicle mileage vary for a given pollutant. This variation implies uncertainty
about the true average emissions of vehicles in that category. To measure this uncertainty,
confidence intervals for the mean of emissions were developed.
As an illustration, in Figure 1 the CO values for the same 32 tests are plotted against
accumulated mileage. Also shown is a 95% confidence band, which can be used to estimate
mean CO with 95% confidence at a given mileage level. The figure displays the
characteristic pattern in which the confidence band widens as mileage diverges from the
sample mean. For this analysis, it was decided to compare the sample data from each model
year to MOBILE6. In order to synthesize results, the mean mileage of a model year
subsample was used to compute the MOBILE6 estimate and also the corresponding 95%
confidence interval from the regression of the sample data.
Figure 2 shows the outcome of these calculations for each of the vehicle type, fuel
metering and model year categories. On a given graph, each vertical bar represents a 95%
confidence interval of the type described above for a particular model year and data source.
The horizontal axis gives the MOBILE6 estimate of emissions at the mean mileage for that
model year subsample. A 45-degree line, labeled ' 1:1' is included to help visualize the
comparison of actual data to the model fit. A point on this line represents exact equality of
the data and the MOBILE6 estimate. Thus, if the bar lies above this line, the FTP data
suggest actual FTP emissions higher than is predicted by MOBILE6. The opposite
conclusion is implied by a bar falling below the 1:1 line. When the bar intersects the 1:1
line, evidence of a difference is inconclusive at the 95% level of confidence. Note that the
number of intervals is not always the same from one data source to another because not all
model years are represented in each of the data sets.
The size of the confidence intervals varies considerably, reflecting great differences
in the group sample sizes as well as the inherent variation in emissions within a sample.
The performance of the MOBILE6 estimates appear rather different among model year-
technology groups. In general, the model tends to equal or overstate emissions in the newer
fuel-injected vehicle classes. With the older model years the results are more mixed. In some
cases, e.g., 1984-93 carbureted trucks, the direction of the discrepancies is clearly a function
of the data source. The overall pattern appears to support the general hypothesis that
MOBILE6 estimates equal or perhaps overestimate emission rates found in actual data.
That the model would overstate the data is clearly to be expected for the
EPA/AAMA/API set since those data were used to fit the deterioration model before the
bias adjustment. In most cases, that adjustment increased the emission rate using the Ohio
EVI240 data.
It has been noted that the Hammond data also are used. The influence of the
Hammond data on this adjustment is less obvious. Because the California surveillance data
was not used in MOBILE6, its relation to the model's estimates is perhaps most useful.
There is no apparent overall tendency in the model to overstate or understate the California
M6.EXH.010 -4- DRAFT 4/30/99
-------
values, although clear patterns are seen in individual model year-technology groups. It
should be noted that emissions, in general, standards in California differ from those of the
other states. For example, for 1988-93 cars the California CO standard is 7.0 grams per mile
compared to the Federal standard of 3.4 gpm. For the same model years, the California NOx
standard varies from 0.4 to 1.0 gpm while the Federal standard is 1.0 gpm. However, it is
difficult to identify a clear pattern in the confidence interval graphs that is consistent with
these differences in standards.
3.2 IM240 Data
The MOBILE6 bias adjustment procedure mentioned earlier relies on a sample of
more than 200,000 EVI240 test measurements collected in Dayton, Ohio during 1996 and
1997. In particular, these were fast-pass tests in which the test length was abbreviated to as
little as 30 seconds for vehicles with sufficiently low emissions. To use these data, it was
necessary to first estimate each vehicle's full 240 second emissions. The resulting values
then were converted to running emission estimates using regression equations developed
from the Hammond, Indiana data.
One question that is raised by this work concerns the sensitivity of the results to the
state-specific characteristics of the EVI240 program. State programs and driving conditions
vary, suggesting the possibility that the Ohio EVI240 data may not be typical of all regions.
To examine this issue, EPA repeated the adjustment calculations using EVI240 data from
Colorado. In particular, regression equations developed from EVI240 data collected in
Wisconsin were used to estimate full EVI240 values (reference 4). The Wisconsin data
offered second-by-second measures of all 240 seconds, enabling the proper correlation of
partial test to full test emissions. Using the same conversion procedure for both Ohio and
Colorado should provide the most direct and specific comparison of the effects of the two
states' data.
The adjustment for FTP sample bias is captured in a term that is added to the running
emissions component of the FTP as computed in MOBILE6. In Version 6, vehicle emissions
are separated into start and running components to provide the model's users greater
flexibility. Start emissions, measured in grams, are the emissions occurring at the beginning
of a trip when the engine is turned on. Running emissions are produced during actual driving
and are measured in grams per mile. The basic emission rate of a vehicle, start or running, is
a function of the vehicle's accumulated mileage. The EVI240-based bias adjustment term
increases linearly with mileage, starting at zero for a new vehicle. It is applied only to
running emissions because the EVI240 test does not properly measure start emissions. For
each pollutant, model year-technology group and vehicle type, the adjustment factor was
calculated from the Colorado EVI240 data in the same way as for the Ohio data. Table 3
shows a comparison of the two states' adjustment factors. In general, the Colorado-based
factors are larger than those of Ohio. To gauge these differences in the context of FTP
emissions, graphs were constructed showing the proposed MOBILE6 deterioration of
emission rates versus mileage and the modified deterioration rates using Colorado's data in
place of Ohio's (Figure 3). The graphs also include the in-use deterioration modeled by
M6.EXH.010 -5- DRAFT 4/30/99
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MOBILES for representative model years. Because MOBILES has different deterioration
line for each model year, the years 1981, 1987 and 1992 were chosen as representative of
their MOBILE6 model year groups. The graphs for model year 1981 are of questionable
value since the Colorado EVI240 data contain only a few vehicles from that year. The method
of computing the adjustment factor for a given model year group requires at least two model
year points (see reference 1). Since one of the two years in the 1981-82 group is poorly
represented, the resulting adjustment factor is dubious.
Several observations can be made. First, differences between the two states are
considerably muted when the adjusted running emission value is merged with start
emissions to form an FTP estimate. Second, the effect of the difference is obviously smaller
at low mileage accumulation than at higher mileages. Finally, these differences are quite
small relative to the change from version 5 to version 6 of MOBILE.
4.0 Conclusions
The estimates of FTP emission rates generated by MOBILE6 appear to agree rather
well on average with rates observed in actual data measurements. Some of the evidence
presented here must be qualified due to the relation between the data and model itself.
Additional sources of independent FTP data would help better illuminate this issue.
State EVI240 data play a key role in the MOBILE6 estimates of running emissions.
The analysis presented here suggests that substituting Colorado EVI240 data for that of Ohio
increases these estimates substantially. When combined with start emission estimates to
obtain full FTP values, the relative effect of this substitution is considerably diminished, and
with either state's data the new model emission rates are much smaller than in MOBILES.
M6.EXH.010 -6- DRAFT 4/30/99
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Table 1: Distribution of Vehicles by Model Year and Technology
for the Combined FTP Data set
[ SOURCE
I i
1
[ CAL SURVEIL
1 4.
1
| ODOMETER
I
1
1
VEH TYPE | MY -TECH
CARS 81-82 CARS
[81-82 FI
[83-85 CARS
[83-87 FI
[86-93 CARS
[88-93 PFI
[88-93 TBI
[ALL
TRUCKS 81-83 CARS
[81-87 FI
[84-93 CARS
[88-93 PFI
[88-93 TBI
[ALL
MEAN
130
126
104
104
100
70
72
90
167
119
109
72
76
99
,028
,617
,863
,615
,565
,975
,035
,078
,371
,129
,451
,045
,373
,995
EPA/AAMA/API
ODOMETER
N
13
12
50
107
40
162
32
416
13
27
38
50
15
143
MEAN
33
42
34
53
56
40
49
41
34
59
47
44
38
42
,954
,609
,940
,556
,097
,759
,127
,960
,934 |
,413
,952
,486
,427
,261
N
I
HAMMOND REWGT*]
i
i
ODOMETER
1166[
126
253
726
96
1605
444
4416
180 [
94
134
330
467
1205
MEAN
92, 408 [
87, 439 [
83, 629 [
70, 988 [
56, 002 [
37, 869 [
38, 524 [
61 ,703 [
•I
•I
N
84 |
I
I
9|
I
I
57 |
I
I
384 [
i
54 |
I
I
202 [
I
I
108 [
I
I
898 [
•I
I
I
•I
I
I
•I
I
I
•I
I
I
•I
I
I
*Weighted total from original sample of 668 tests.
M6.EXH.010
DRAFT 4/30/99
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Table 2: Distribution of Vehicles by Model Year and Technology
for the Colorado IM240 Data set
COLORADO
CARS I TRUCKS
+ +
FI CARS | FI | CARS | FI
OHIO
CARS | TRUCKS
I CARS | FI | CARS
| MY
19
19
19
19
19
19
19
19
19
19'
19'
19'
19'
19'
19'
ALL
1981 [ 2 1
1982 | 5,269]
1983 [ 9,393]
1984 [ 16,064]
1985 | 29,209]
1 986 | 34 , 996 1
1987 | 47,897]
1988 | 52,663]
1989 | 60,572]
1 990 | 64 , 924 |
1991 | 71,911]
1992 | 60,421]
1993 | 70,135]
1994 | 62,901]
1995 [ 33,049]
4. 4.
6]
17,079]
23,346]
27,429]
29,306]
22,937]
20,519]
14,601 |
11 ,816]
1,087]
320]
64]
2]
0]
0]
4.
0]
176]
129]
660]
2,129]
14,670]
19,768]
27,238]
29,956]
27,493]
34,487]
33,407]
42,666]
45,567]
19,985]
4-
2] 140]
7,209] 882] 2,
12,210] 998] 2,
20,430] 4,146 7,
24,403] 4,542 4,
11,914] 11,207 6,
6,436] 8,041 2,
2,177] 16,367 3,
1,761] 10,117 1,
2,038] 16,606
233] 9,519]
108] 16,604]
45] 10,646]
0] 13,740]
0] 7,895]
4- 4-
924] 7] 15E
767 19 862
791 5 73E
105 87 2,18S
329 316 1,74£
771 2,873 1,80E
777 2,278 626
092 5,236 44C
399 3,231 82
267 4,271 11E
7 3,074 (.
0 5,289 C
0] 3,517 C
0] 5,061 C
0[ 2,528 C
4. 4.
619,406] 168,512] 298,331] 88,966 131,450 32,229 37,792 8,771
M6.EXH.010
DRAFT 4/30/99
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Table 3: IM240-Based Additive Adjustment Factors
Colorado vs. Ohio, grams/mile per 1000 miles
CARS
1
1
1
1
1
1
1
1
1
| MY -TECH
I
1
[81-82 CARS
I
I
[81-82 FI
I
I
[83-85 CARS
I
I
[83-87 FI
I
I
[86-93 CARS
I
I
[88-93 PFI
I
I
[88-93 TBI
TRUCKS
[GROUP
I
I
[81-83 CARS
I
I
[81-87 FI
I
I
[84-93 CARS
I
I
[88-93 PFI
I
I
[88-93 TBI
[ HC [ CO
I + +
I f f
[ STATE STATE
I + +
I f f
[COLORADO OHIO COLORADO OHIO
I I I I I
I I I I I
"I I I I I
0.0087 0.0048 0.2402 0.1419[
0.0113 0.0094 0.1443 0.1825[
0.0029 0.0003 0.0209 -0.0200[
0.0013 -0.0001 0.0031 -0.0048[
0.0045 0.0039 0.0854 0.0729[
0.0018 0.0013 0.0356 0.0313[
0.0018 0.0013 0.0356 0.0313[
I I I I I
I I I I I
"I I I I I
0.0094 0.0018 0.3499 0.1044[
-0.0008 -0.0037 0.0973 0.0550[
-0.0012 -0.0053 0.0097 -0.0658[
0.0021 0.0013 0.0471 0.0329[
0.0021 0.0013 0.0471 0.0329[
NOX
STATE
COLORADO [
0.0002 [
-0.0065[
0.0000 [
0.0026 [
0.0025 [
0.0022 [
0.0022 [
-0.0020[
-0.0015[
-0.0034[
0.0015[
0.0015[
1
1
1
1
OHIO [
0.0002[
-0.0060[
0.0003[
0.0023[
0.0021 [
0.0010[
0.0010[
0.0008[
-0.0028[
-0.0040[
0.0002[
0.0002[
M6.EXH.010
DRAFT 4/30/99
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25^
Figure 1: 1988-93 CO for CALIFORNIA SURVEILLANCE SAMPLE
with 95% CONFIDENCE BANDS for MEAN EMISSION RATE
20:-
15:
0
o
10:
5:;
• •-*•-•-
w ^ * A
^-1 • •
-* • * I
i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i r
0
40
80
MILES (X1000)
120
160
-------
Figure 2: HC COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILE6 ESTIMATES
1988-93 PFI CARS: 95% CONFIDENCE INTERVALS
0.0
0.0
0.2
0.4
HC MOBILES (g/mi)
1:1
EPA/AAMA/API
CAL SURVEIL
HAMMOND REWGT
0.6
-------
Figure 2: HC COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILE6 ESTIMATES
1988-93 TBI CARS: 95% CONFIDENCE INTERVALS
0.0
0.0
0.2
0.4
HC MOBILES (g/mi)
1:1
EPA/AAMA/API
CAL SURVEIL
HAMMOND REWGT
0.6
-------
Figure 2: HC COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILE6 ESTIMATES
1986-93 CARB CARS: 95% CONFIDENCE INTERVALS
I
I
O
X
2.(H
1.5:
1.0:
0.5:
0.0:
-0.5:
\ i i i i i i i i i i i i i i i i i i i i i i i i r
0.0
0.5
1.0
HC MOBILES (g/mi)
1:1
EPA/AAMA/API
CAL SURVEIL
HAMMOND REWGT
1.5
-------
Figure 2: HC COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILE6 ESTIMATES
1983-87 Fl CARS: 95% CONFIDENCE INTERVALS
0.0
0.5
1.0
HC MOBILES (g/mi)
1:1
EPA/AAMA/API
CAL SURVEIL
HAMMOND REWGT
1.5
-------
Figure 2: HC COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILE6 ESTIMATES
1983-85 CARB CARS: 95% CONFIDENCE INTERVALS
0.0
0.5
1.0
HC MOBILES (g/mi)
1:1
EPA/AAMA/API
CAL SURVEIL
HAMMOND REWGT
1.5
-------
Figure 2: HC COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILE6 ESTIMATES
1981-82 Fl CARS: 95% CONFIDENCE INTERVALS
8
6:
I
I
O
X
2:
0:
\ i i i i i i r
0
i i i i i i i i i r
HC MOBILES (g/mi)
1:1
EPA/AAMA/API
CAL SURVEIL
HAMMOND REWGT
\ i i i i r
-------
Figure 2: HC COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILE6 ESTIMATES
1981-82 CARB CARS: 95% CONFIDENCE INTERVALS
0
HC MOBILES (g/mi)
1:1
EPA/AAMA/API
CAL SURVEIL
HAMMOND REWGT
-------
Figure 2: CO COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILES ESTIMATES
1988-93 PFI CARS: 95% CONFIDENCE INTERVALS
I
0
O
0
CO MOBILES (g/mi)
1:1
EPA/AAMA/API
CAL SURVEIL
HAMMOND REWGT
8
10
-------
Figure 2: CO COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILES ESTIMATES
1988-93 TBI CARS: 95% CONFIDENCE INTERVALS
12
0
CO MOBILES (g/mi)
1:1
EPA/AAMA/API
CAL SURVEIL
HAMMOND REWGT
8
-------
Figure 2: CO COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILES ESTIMATES
1986-93 CARB CARS: 95% CONFIDENCE INTERVALS
40
30:
Z 20
I
0
o
10:
0:
0
10
CO MOBILES (g/mi)
15
1:1
EPA/AAMA/API
CAL SURVEIL
HAMMOND REWGT
20
-------
Figure 2: CO COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILES ESTIMATES
1983-87 Fl CARS: 95% CONFIDENCE INTERVALS
40
8 10
0
10
CO MOBILES (g/mi)
15
1:1
EPA/AAMA/API
CAL SURVEIL
HAMMOND REWGT
20
-------
Figure 2: CO COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILES ESTIMATES
1983-85 CARB CARS: 95% CONFIDENCE INTERVALS
40
8 10
0
10
CO MOBILES (g/mi)
1:1
EPA/AAMA/API
CAL SURVEIL
HAMMOND REWGT
20
-------
Figure 2: CO COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILES ESTIMATES
1981-82 Fl CARS: 95% CONFIDENCE INTERVALS
60
40
2 20-
I
0
o
0:
-20:
\ i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i r
0
10
20
30
CO MOBILES (g/mi)
1:1
EPA/AAMA/API
CAL SURVEIL
HAMMOND REWGT
40
50
-------
Figure 2: CO COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILES ESTIMATES
1981-82 CARB CARS: 95% CONFIDENCE INTERVALS
70
0
20
40
CO MOBILES (g/mi)
1:1
EPA/AAMA/API
CAL SURVEIL
HAMMOND REWGT
60
-------
Figure 2: NOX COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILES ESTIMATES
1988-93 PFI CARS: 95% CONFIDENCE INTERVALS
0.0
0.0
0.2
0.4
0.6
NOX MOBILES (g/mi)
1:1
EPA/AAMA/API
CAL SURVEIL
HAMMOND REWGT
0.8
1.0
-------
Figure 2: NOX COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILES ESTIMATES
1988-93 TBI CARS: 95% CONFIDENCE INTERVALS
0.0
0.0
0.2
0.4
0.6
NOX MOBILES (g/mi)
1:1
EPA/AAMA/API
CAL SURVEIL
HAMMOND REWGT
0.8
1.0
-------
Figure 2: NOX COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILES ESTIMATES
1986-93 CARB CARS: 95% CONFIDENCE INTERVALS
f
0.0
0.0
0.5
1.0
NOX MOBILES (g/mi)
1:1
EPA/AAMA/API
CAL SURVEIL
HAMMOND REWGT
1.5
-------
Figure 2: NOX COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILES ESTIMATES
1983-87 Fl CARS: 95% CONFIDENCE INTERVALS
I
8
1.0:
0.5:
0.0
0.0
0.5
1.0
NOX MOBILES (g/mi)
1.5
1:1
EPA/AAMA/API
CAL SURVEIL
HAMMOND REWGT
2.0
-------
Figure 2: NOX COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILES ESTIMATES
1983-85 CARB CARS: 95% CONFIDENCE INTERVALS
0.0
0.0
0.5
1.0
NOX MOBILES (g/mi)
1:1
EPA/AAMA/API
CAL SURVEIL
HAMMOND REWGT
1.5
-------
Figure 2: NOX COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILES ESTIMATES
1981-82 Fl CARS: 95% CONFIDENCE INTERVALS
f
8
1-
0.0
0.5
1.0
NOX MOBILES (g/mi)
1.5
1:1
EPA/AAMA/API
CAL SURVEIL
HAMMOND REWGT
2.0
-------
Figure 2: NOX COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILES ESTIMATES
1981-82 CARB CARS: 95% CONFIDENCE INTERVALS
f
8
1-
0.0
0.5
1.0
NOX MOBILES (g/mi)
1.5
1:1
EPA/AAMA/API
CAL SURVEIL
HAMMOND REWGT
2.0
-------
Figure 2: HC COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILE6 ESTIMATES
1988-93 PFI TRUCKS: 95% CONFIDENCE INTERVALS
0
0
1:1
HC MOBILES (g/mi)
CAL SURVEIL
EPA/AAMA/API
-------
Figure 2: HC COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILE6 ESTIMATES
1988-93 TBI TRUCKS: 95% CONFIDENCE INTERVALS
0
0
1:1
HC MOBILES (g/mi)
CAL SURVEIL
EPA/AAMA/API
-------
Figure 2: HC COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILE6 ESTIMATES
1984-93 CARB TRUCKS: 95% CONFIDENCE INTERVALS
I
I
O
I
-1-
0.0
0.5
1.0
HC MOBILES (g/mi)
1.5
1:1
CAL SURVEIL
EPA/AAMA/API
-------
Figure 2: HC COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILE6 ESTIMATES
1981-87 Fl TRUCKS: 95% CONFIDENCE INTERVALS
0
0.0
0.2
0.4
0.6
HC MOBILES (g/mi)
0.8
1.0
1:1
CAL SURVEIL
EPA/AAMA/API
-------
Figure 2: HC COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILE6 ESTIMATES
1981-83 CARB TRUCKS: 95% CONFIDENCE INTERVALS
4:
z 3
i
o
I
1:
0
0.0
0.5
1.0
HC MOBILES (g/mi)
1.5
1:1
CAL SURVEIL
EPA/AAMA/API
-------
Figure 2: CO COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILES ESTIMATES
1988-93 PFI TRUCKS: 95% CONFIDENCE INTERVALS
50
0
0
10
20
30
40
50
CO MOBILES (g/mi)
1:1
CAL SURVEIL
EPA/AAMA/API
-------
Figure 2: CO COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILES ESTIMATES
1988-93 TBI TRUCKS: 95% CONFIDENCE INTERVALS
60
0
0
\ i i i i i i i i i i i i i i i i i r
i i i i i i i i i i i i i i r
10
20 30
40
50
60
CO MOBILE6 (g/mi)
1:1
CAL SURVEIL
EPA/AAMA/API
-------
Figure 2: CO COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILES ESTIMATES
1984-93 CARB TRUCKS: 95% CONFIDENCE INTERVALS
40
0
0
10
15
20
25
CO MOBILES (g/mi)
1:1
CAL SURVEIL
EPA/AAMA/API
-------
Figure 2: CO COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILES ESTIMATES
1981-87 Fl TRUCKS: 95% CONFIDENCE INTERVALS
50
0
0
10
15
CO MOBILES (g/mi)
1:1
CAL SURVEIL
EPA/AAMA/API
-------
Figure 2: CO COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILES ESTIMATES
1981-83 CARB TRUCKS: 95% CONFIDENCE INTERVALS
70-
50-
I
i
0
o
30-
10
T
\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ r
0
10
15
20
25
CO MOBILES (g/mi)
1:1
CAL SURVEIL
EPA/AAMA/API
-------
Figure 2: NOX COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILES ESTIMATES
1988-93 PFI TRUCKS: 95% CONFIDENCE INTERVALS
0.0-
0.0
0.5
1.0
NOX MOBILES (g/mi)
1.5
2.0
1:1
CAL SURVEIL
EPA/AAMA/API
-------
Figure 2: NOX COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILES ESTIMATES
1988-93 TBI TRUCKS: 95% CONFIDENCE INTERVALS
0.0-
0.0
0.5
1.0
NOX MOBILES (g/mi)
1.5
2.0
1:1
CAL SURVEIL
EPA/AAMA/API
-------
Figure 2: NOX COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILES ESTIMATES
1984-93 CARB TRUCKS: 95% CONFIDENCE INTERVALS
2-
l
1
\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \
0.0
0.5
1.0
NOX MOBILES (g/mi)
1.5
1:1
CAL SURVEIL
EPA/AAMA/API
-------
Figure 2: NOX COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILES ESTIMATES
1981-87 Fl TRUCKS: 95% CONFIDENCE INTERVALS
0)
2-
1
8
1-
0
0.0
0.5
1.0
NOX MOBILES (g/mi)
1.5
1:1
CAL SURVEIL
EPA/AAMA/API
-------
Figure 2: NOX COMPARISON OF ACTUAL FTP DATA WITH PROPOSED OHIO-BASED MOBILES ESTIMATES
1981-83 CARB TRUCKS: 95% CONFIDENCE INTERVALS
I
1
i
0.0
0.5
1.0
NOX MOBILES (g/mi)
1.5
2.0
1:1
CAL SURVEIL
EPA/AAMA/API
-------
Figure 3: FTP COMPARISON OF PROPOSED MOBILES HC EMISSION FACTORS
1992 CARS: OHIO vs COLORADO IM240 ADJUSTED
HC (g/mi)
5:
4:
3:
2:
1:
0:
0
50
100
MILES (xlOOO)
150
200
OHIO -ADJUSTED MOBILES
COLORADO -ADJUSTED MOBILES
MOBILE5
-------
Figure 3: FTP COMPARISON OF PROPOSED MOBILES HC EMISSION FACTORS
1987 CARS: OHIO vs COLORADO IM240 ADJUSTED
HC (g/mi)
5:
4:
3:
2:
1:
0:
0
50
100
MILES (xlOOO)
150
200
OHIO -ADJUSTED MOBILES
COLORADO -ADJUSTED MOBILES
MOBILE5
-------
Figure 3: FTP COMPARISON OF PROPOSED MOBILES HC EMISSION FACTORS
1981 CARS: OHIO vs COLORADO IM240 ADJUSTED
HC (g/mi)
5
4
2-
0
0
50
100
MILES (xlOOO)
150
200
OHIO -ADJUSTED MOBILES
COLORADO -ADJUSTED MOBILES
MOBILE5
-------
Figure 3: FTP COMPARISON OF PROPOSED MOBILES CO EMISSION FACTORS
1992 CARS: OHIO vs COLORADO IM240 ADJUSTED
CO (g/mi)
70
60
50
40
30:
20:
10
0
0
50
100
MILES (xlOOO)
150
200
OHIO -ADJUSTED MOBILES
COLORADO -ADJUSTED MOBILES
MOBILE5
-------
Figure 3: FTP COMPARISON OF PROPOSED MOBILES CO EMISSION FACTORS
1987 CARS: OHIO vs COLORADO IM240 ADJUSTED
CO (g/mi)
70
60
50
40
30:
20:
10
0
0
50
100
MILES (xlOOO)
150
200
OHIO -ADJUSTED MOBILES
COLORADO -ADJUSTED MOBILES
MOBILE5
-------
Figure 3: FTP COMPARISON OF PROPOSED MOBILES CO EMISSION FACTORS
1981 CARS: OHIO vs COLORADO IM240 ADJUSTED
CO (g/mi)
70
60
50
40
30:
20:
10
0
0
50
100
MILES (xlOOO)
150
200
OHIO -ADJUSTED MOBILES
COLORADO -ADJUSTED MOBILES
MOBILE5
-------
Figure 3: FTP COMPARISON OF PROPOSED MOBILE6 NOX EMISSION FACTORS
1992 CARS: OHIO vs COLORADO IM240 ADJUSTED
NOX (g/mi)
3:
2:
1:
0
0
50
100
MILES (xlOOO)
150
200
OHIO -ADJUSTED MOBILES
COLORADO -ADJUSTED MOBILES
MOBILE5
-------
Figure 3: FTP COMPARISON OF PROPOSED MOBILE6 NOX EMISSION FACTORS
1987 CARS: OHIO vs COLORADO IM240 ADJUSTED
NOX (g/mi)
3:
2:
1:
0
0
50
100
MILES (xlOOO)
150
200
OHIO -ADJUSTED MOBILES
COLORADO -ADJUSTED MOBILES
MOBILE5
-------
Figure 3: FTP COMPARISON OF PROPOSED MOBILE6 NOX EMISSION FACTORS
1981 CARS: OHIO vs COLORADO IM240 ADJUSTED
NOX (g/mi)
3:
2:
1:
0
0
50
100
MILES (xlOOO)
150
200
OHIO -ADJUSTED MOBILES
COLORADO -ADJUSTED MOBILES
MOBILE5
------- |