United States Air and Radiation EPA420-R-01-011
Environmental Protection April 2001
Agency M6.FLT.003
vvEPA Soak Length Activity
Factors for Start
Emissions
> Printed on Recycled Paper
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EPA420-R-01-011
April 2001
for
M6.FLT.003
Edward L. Glover
David J. Brzezinski
Assessment and Standards Division
Office of Transportation and Air Quality
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.
-------
1.0 INTRODUCTION
MOBILE6 will compute and report (as a user option) hourly emission factors for start,
running, and evaporative emissions. These outputs will be in addition to the standard daily emission
estimates which are currently calculated by MOBILES. The hourly emission factors will allow the
MOBILE6 model to provide more precise output that accounts for the time of day that vehicle
emissions occur. The temporal distribution of emissions is an important factor in the formation of
diurnal evaporative and start emissions.
The hourly emission estimates require considerable vehicle activity information and analysis.
The term "activity" refers to the vehicle's operating mode such as running, idling, parked (soaking),
etc. The specific activity information needed for emissions estimates includes soak durations, time
of soak, trip lengths in minute and miles, time of trip, timing of the soak with respect to the engine
operation (before or after) and other information. This document (M6.FLT.003) discusses the issue
of vehicle soak time only as it pertains to start emissions. Other activity estimates needed to
develop daily emission factors for exhaust, diurnal, running loss or resting loss emissions are
documented in MOBILE6 documents (M6FLT004, M6FLT005, and M6FLT006).
2.0 DATA SOURCES USED
The primary data source for this analysis are the EPA instrumented vehicle studies conducted
in Baltimore and Spokane. In these studies, instrumentation to monitor vehicle usage was installed
with the motorists' permission on 168 randomly selected vehicles while they were tested at an
Inspection / Maintenance (I/M) station. The motorists returned one or two weeks later to have the
instrumentation removed. Information from more than 8,500 vehicle-trips was recorded. The raw
data collected from the studies were processed by the Radian Corporation under EPA contract to
create a "trip characteristics" file. This processed file was used to develop the hourly soak time
distributions. For more details regarding the instrumented vehicle studies and the data processing,
please refer to the document "Travel Trip Characteristics Analysis" Final Report under EPA Contract
68-C1-0079 WA 2-05 with Sierra Research.
3.0 METHODOLOGY
This section describes the basic methodology used to develop the soak activity estimates used
in the calculation of start emissions. The process involved several steps. These are discussed
below.
3.1 Definition of a Soak
-------
For the purpose of activity estimates for start emissions, a soak is defined as the duration of
time preceding a vehicle start in which the vehicle's engine is not operating, and the ensuing vehicle
start did not result in a stall (stalls were removed from the database). Throughout this document the
duration of the soak in units of time will be referred to as the "soak length". Also, by convention,
if this soak period preceding the vehicle start is less than 12 hours then the engine start is a "hot
start". If the soak period preceding the vehicle start is more than 12 hours then the engine start is
a "cold start". Vehicle start emissions which are defined as "cold start" are assumed not to vary
based on the prior soak length (as long as the length exceeds 12 hours). The 12 hour period was
chosen for consistency with the Federal Test Procedure definition of a cold start.
3.2 Hourly Intervals
The 24 hour day was divided into 14 different hourly groups. Thirteen of these groups have
a duration of one hour. These start at 6:OOAM and run through 7:59:59PM. The fourteenth hour
contains the remaining nighttime and early morning hours as one interval. Collapsing these hours
into one was done for three reasons: (1) the emissions contributed during the night have a relatively
smaller impact on daily ozone or CO formation than those contributed during the morning or day,
(2) there were relatively little data for these time periods, and (3) what data were available produced
results which showed very little hour to hour variance. The hourly intervals are shown in Table 1.
Factors Affecting Start Activity Values
3.3.1 Weekdays Versus Weekends
For a number of the soak parameters, a significant difference existed between the value for
the weekday and the value for the weekend. Conceptually this make sense since most motorists have
different usage patterns for their vehicles on weekdays than on weekends. Differences may also exist
for the various days of the week; however, the database was too small to reliably discern these
differences.
The MOBILE6 model will distinguish between weekend and weekday in terms of activity
and emissions, and a user input will be required to tell the model which one is to be reported. The
default will likely be the "weekday."
Table 1
Hourly Intervals
MOBILE6 Hourly Index
1
Military Time Range
6-7
Time
6 am to 7 am
-------
2
3
4
5
6
7
8
9
10
11
12
13
14-24
7-8
8-9
9- 10
10- 11
11 - 12
12- 13
13- 14
14- 15
15- 16
16- 17
17- 18
18- 19
19 -24 and 24 -6
7 am to 8 am
8 am to 9 am
9 am to 10 am
10 am to 11 am
1 1 am to noon
noon to 1 pm
1 pm to 2 pm
2 pm to 3 pm
3 pm to 4 pm
4 pm to 5 pm
5 pm to 6 pm
6 pm to 7 pm
7 pm to 6 am
3.3.2 Vehicle Type and Model Year
The vehicle "start" activity parameters such as the number of trips per day, and the
distribution of soak time after the trip end were also investigated by vehicle type or vehicle age.
Slight differences were found between cars and trucks in terms of starts per day, with trucks having
slightly more starts per day (shown in Table 2a). However, little significant difference in the hourly
soak length distributions were found between cars and trucks or even by vehicle model year. The
lack of difference in the hourly distributions between cars and trucks was not particularly surprising
since the number of trips per day are fairly similar, and most light trucks today play virtually the
same role as cars. Exceptions might be in rural areas or heavily industrial areas where light trucks
more frequently are used to haul equipment or products.
The lack of difference between model years is a little more surprising. One would expect an
older vehicle to have a higher percentage of longer soaks, and possibly shorter trips (i.e., the vehicle
sits more and goes on fewer long trips because it is a second vehicle). However, a limited analysis
of the data did not conclusively demonstrate these hypotheses. One reason might be the relatively
small sample of older vehicles. For example, less than 15 percent of the vehicle sample were more
than 10 years old at the time of the testing. This was also too small a sub-sample to further split into
28 hourly and weekday/weekend groups, and still obtain reasonable results. The other reason might
-------
be recruitment process which was biased to obtain vehicles which were a motorists' primary vehicles
rather than spare second vehicles. As a result, the hourly distributions of soak length shown in
Tables 3a and 3b and 4a and 4b represent both cars and trucks and all vehicle ages.
Since the default MOBILE6 hourly activity estimates are based exclusively on 168 vehicles,
and thus cannot possibility reflect all geographical areas, times, or other variables, the user will have
the option of providing data on soak length prior to vehicle starts into the MOBILE6 model from an
external file.
3.4 Starts per Car-Day
The first necessary parameter in the model is the estimate for starts/car-day. Four different
estimates were developed. There is one estimate for each combination of car versus truck and
weekday versus weekend. These are average values obtained from the instrumented vehicle
database. The values are shown in Table 2a.
Table 2a
Starts per Car per Day
Cars
Weekday
7.28
Weekend
5.41
Trucks
Weekday
8.06
Weekend
5.68
3.5 Daily Start Distribution by Time of Day Increment
Table 2b contains the distribution of the vehicle starts by hourly group. An estimate is
provided for each of the fourteen groups, and separate estimates are provided for weekends and
weekdays. For example, Table 2b shows that approximately 2.04 percent of the starts occur during
the period from 6:00 AM to 6:59:59 AM. The data which underlies Table 2b were obtained from
the instrument vehicle database. Each column sums to 100 percent.
-------
Table 2b
Distribution of Starts bv Hour (in p
MOBILE6 Hourly Index
1
2
3
4
5
6
7
8
9
10
11
12
13
14-24
Weekday
2.04
5.54
6.02
4.73
5.16
6.72
8.07
7.30
8.04
8.98
8.41
7.73
6.02
15.24
>ercent)
Weekend
0.91
1.93
3.10
6.45
6.91
7.97
10.16
7.26
8.89
7.36
8.02
7.11
6.15
17.78
3.6 Soak Length Distribution Within Each Hourly Group
The MOBILE6 model will contain a soak length distribution for each of the 14 hourly
groups, and for both weekdays and weekends. As a result, there will be 28 soak length distributions.
Each of the 28 distributions contains 70 values. The use of 70 values to represent the entire 720
minute distribution saves computing time and memory. The time intervals represented by these 70
soak lengths are shown in the leftmost column in Table 3a and 3b and Table 4a and 4b. Tables 3a
and 3b show the soak length distributions for weekdays, and Table 4a and 4b show the soak length
distributions for weekends. The first column in the tables is the soak length interval in minutes.
-------
The remaining columns in Tables 3a and 3b and Tables 4a and 4b are the soak length
distributions. Each entry in a given column represents the precentage of the distribution for a given
interval. For example, in Table 3a the column labeled "six" represents 6:OOAM to 6:59:59 AM. The
first entry in the column (1.55039%) is the percent of soaks that occur between 6:OOAMto 6:59:59
AM that are less than one minute which were not stalls. The remaining entries in the column are
analogous. The final entry at 720+ is the percent of soak which are longer than 720 minutes
(45.7364%). Summing the column should give a total value of 100 percent. Vehicle stalls were not
used.
The use of a lookup table to contain the cumulative soak length distribution of each hourly
group was necessary because no smooth functional form could be found which adequately fit the
data for all of the groups. This can be seen in Figure 1 which shows the cumulative distribution
versus soak length for the weekday 6-7 AM group (denoted as "six" in the legend), the weekday
8-9 AM group (denoted as "eight" in the legend), and the weekday 1-2 PM group (denoted as
"thirteen" in the legend). Notice the considerable differences between these distributions, and their
difficult to fit data profiles. For example, the 6 to 7 AM distribution tends to rise quickly to 20
percent, level off around 20 percent until 450 minutes, and then start an upward movement. This
is in direct contrast to the cumulative distribution of the 1 to 2 PM group which shows a very rapid
rise at first and an asymptotic shape as 720 minutes is approached.
3.7 Using the Soak Activities in the MOBILE6 Model
3.7.1 Hourly Start Emission Calculations
The start emission effects for each of the 70 soak length intervals in grams (see document
M6.STE.003) are multiplied by the analogous soak length activity percentages shown in Tables 3a
through 4b. As noted in Section 3.6 there are 70 intervals, some of which last longer than one
minute, rather than 720 one minute intervals. An average start emission value (in grams) for a given
hourly group is obtained by summing the 70 start emission and activity products together. This sum
is then multiplied by the number of starts per day per vehicle which occur in the given hourly group
to produce the average start emission emission level for the given hourly group. This procedure was
repeated for all of the 14 hourly and weekday and weekend groups to produce an average hourly start
emission value for each group. These hourly average start emission values will be reported by the
MOBILE6 model directly.
As an example calculation: the number of starts per vehicle for a given hourly group is
calculated for the 10 to 11 AM weekday hourly group for cars by multiplying 7.28 starts/day-car x
5.16 percent (Table 2b) = 0.376 starts/vehicle.
3.7.2 Daily Start Emission Calculations
-------
The individual hourly start emission values will also be used to calculate an average daily
start emission value in MOBILE6. This value is analogous to those reported by MOBILE4 and
MOBILES. It is the product of the number of starts per day, and a weighted average of the average
hourly start emissions. The average number of starts per day are shown in Table 2a. The hourly
weighting factors used to weight the hourly groups together are the values shown in Table 2b.
-------
time
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
32
34
36
38
40
42
44
46
48
50
52
54
56
58
60
90
120
150
180
210
240
270
300
330
360
390
420
450
480
510
540
570
600
630
660
690
720
720+
six
1.55039
3.87597
3.10078
2.32558
1.55039
0.77519
0.77519
0.00000
1.55039
0.77519
0.77519
0.77519
0.00000
0.00000
0.00000
0.00000
0.00000
0.77519
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.77519
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.77519
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.77519
0.77519
3.10078
5.42636
3.10078
2.32558
3.87597
1.55039
4.65116
4.65116
3.87597
45.73643
seven
2.51397
2.51397
6.14525
3.35196
3.07263
0.55866
0.83799
1.11732
0.55866
0.27933
0.55866
0.27933
0.55866
0.55866
0.55866
0.55866
0.00000
0.27933
0.83799
0.00000
0.55866
0.83799
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.27933
0.27933
0.00000
0.00000
0.55866
0.00000
0.27933
0.00000
0.00000
0.27933
0.00000
0.55866
0.27933
0.27933
0.00000
0.27933
0.00000
0.00000
0.00000
0.27933
0.00000
0.00000
0.00000
0.27933
0.00000
0.27933
0.27933
0.27933
0.27933
0.55866
1.39665
1.11732
0.83799
1.11732
2.79330
1.67598
5.58659
3.63128
3.91061
3.35196
42.73743
Table 3a - Weekdays
eight
2.86458
4.42708
4.16667
3.12500
2.34375
2.34375
3.38542
2.08333
1.30208
0.26042
2.60417
1.82292
1.30208
1.56250
1.04167
1.04167
0.52083
1.56250
1.04167
1.04167
1.30208
0.00000
0.78125
0.00000
0.78125
0.26042
0.52083
0.78125
0.26042
0.00000
0.26042
0.78125
0.78125
0.26042
1.04167
0.52083
0.00000
0.52083
0.00000
0.52083
0.78125
0.00000
0.00000
0.00000
0.26042
0.26042
1.30208
0.26042
0.26042
0.00000
0.00000
0.26042
0.00000
0.26042
0.00000
0.00000
0.00000
0.26042
0.26042
0.26042
0.00000
0.52083
1.82292
2.34375
0.78125
1.56250
1.56250
2.60417
35.15625
nine
0.66890
4.68227
5.01672
5.35117
2.67559
2.00669
2.34114
1.00334
1.33779
0.66890
1.67224
2.00669
2.67559
1.00334
0.66890
1.00334
1.33779
1.00334
0.33445
1.00334
1.33779
0.33445
1.00334
0.00000
2.34114
1.00334
0.66890
0.33445
0.33445
0.33445
1.00334
1.33779
0.33445
0.00000
0.66890
1.00334
1.33779
0.66890
0.00000
2.00669
0.00000
0.33445
0.33445
0.33445
0.66890
0.00000
6.02007
4.01338
2.34114
0.00000
0.00000
0.33445
0.33445
0.00000
0.00000
0.00000
0.33445
0.00000
0.33445
0.00000
0.00000
0.66890
0.66890
0.66890
1.00334
0.66890
2.00669
0.33445
24.08027
ten
1.54321
6.17284
6.17284
4.01235
4.01235
2.16049
3.39506
1.23457
0.61728
0.92593
1.85185
2.46914
1.23457
0.30864
1.23457
0.92593
0.61728
1.23457
1.23457
0.61728
1.54321
1.23457
0.61728
1.54321
0.61728
0.00000
0.92593
0.00000
0.00000
0.92593
0.30864
0.92593
0.61728
1.23457
0.30864
1.23457
0.92593
1.23457
0.61728
0.61728
1.85185
0.92593
0.61728
0.92593
0.30864
0.30864
7.40741
4.01235
1.85185
0.30864
0.92593
1.23457
0.30864
0.30864
0.61728
0.30864
0.30864
0.30864
0.00000
0.30864
0.00000
0.61728
0.61728
0.30864
0.61728
0.61728
1.23457
0.30864
15.12346
eleven
2.10280
1.86916
4.67290
4.90654
4.67290
3.27103
3.73832
3.27103
1.16822
3.03738
0.93458
1.86916
3.27103
0.93458
0.70093
1.16822
0.93458
1.40187
0.46729
0.70093
0.70093
1.16822
0.46729
1.40187
0.46729
0.46729
0.93458
0.46729
1.16822
0.23364
0.46729
1.63551
1.40187
1.16822
0.46729
1.40187
0.46729
1.40187
0.46729
0.93458
0.70093
0.46729
0.23364
0.70093
0.23364
0.00000
4.90654
4.90654
3.03738
3.03738
2.33645
2.80374
2.57009
0.00000
0.23364
0.00000
0.70093
0.23364
0.00000
0.23364
0.00000
0.00000
0.23364
0.00000
0.46729
0.46729
0.23364
0.00000
8.87850
twelve
1.71756
4.96183
5.53435
4.96183
4.77099
2.48092
3.81679
2.09924
2.09924
1.71756
0.95420
1.90840
1.90840
0.57252
1.14504
1.52672
0.95420
1.14504
0.76336
1.90840
1.33588
0.95420
0.57252
0.76336
0.57252
0.38168
1.14504
0.57252
0.19084
0.57252
0.38168
1.14504
2.09924
1.33588
0.57252
0.76336
1.14504
0.95420
0.95420
0.38168
0.38168
0.76336
1.52672
0.76336
1.33588
0.38168
5.15267
2.29008
1.90840
2.29008
1.71756
2.86260
3.62595
2.29008
0.38168
0.76336
0.00000
0.00000
0.38168
0.38168
0.00000
0.00000
0.00000
0.00000
0.38168
0.00000
0.19084
0.00000
6.48855
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time
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
32
34
36
38
40
42
44
46
48
50
52
54
56
58
60
90
120
150
180
210
240
270
300
330
360
390
420
450
480
510
540
570
600
630
660
690
720
720+
thirteen
2.15054
3.87097
4.94624
3.87097
4.08602
3.22581
3.22581
2.15054
2.58065
2.15054
1.29032
2.58065
1.93548
1.29032
1.50538
1.50538
0.86022
0.86022
1.07527
1.72043
0.21505
1.29032
2.15054
0.21505
1.50538
1.29032
0.86022
0.21505
1.07527
0.86022
0.64516
0.64516
1.72043
0.86022
1.07527
0.64516
1.07527
0.64516
1.07527
0.43011
0.64516
0.86022
0.43011
0.43011
0.86022
0.00000
6.45161
1.93548
3.01075
1.93548
1.72043
2.15054
1.07527
1.07527
1.07527
0.21505
1.07527
0.64516
0.21505
0.21505
0.43011
0.64516
0.00000
0.43011
0.00000
0.00000
0.00000
0.00000
7.09677
fourteen
1.36452
4.87329
4.87329
4.67836
1.94932
4.67836
2.72904
3.11891
2.53411
2.33918
1.94932
1.75439
1.36452
1.75439
0.97466
0.38986
0.19493
1.36452
1.55945
0.38986
0.77973
0.38986
1.16959
0.77973
0.77973
0.58480
0.77973
1.16959
0.77973
0.19493
0.58480
1.36452
1.36452
1.75439
0.97466
0.97466
0.77973
0.58480
0.77973
1.75439
0.00000
0.58480
0.58480
0.97466
0.97466
0.38986
7.21248
4.67836
4.28850
2.33918
1.36452
1.36452
0.77973
0.97466
0.58480
0.19493
1.16959
0.97466
1.36452
0.19493
0.38986
0.77973
0.38986
0.00000
0.00000
0.19493
0.00000
0.00000
4.09357
Table 3b - Weekdays
fifteen
1.39616
3.83944
5.93368
4.71204
3.49040
3.66492
4.01396
2.61780
2.61780
1.74520
2.44328
1.57068
1.57068
1.22164
0.69808
1.04712
1.04712
0.34904
1.22164
0.69808
1.04712
0.87260
1.04712
1.04712
0.69808
0.69808
0.17452
0.34904
0.52356
0.34904
0.52356
1.22164
0.69808
0.34904
1.22164
1.39616
0.52356
1.04712
1.22164
0.34904
0.17452
0.34904
0.52356
0.87260
0.52356
0.17452
5.58464
4.01396
2.44328
3.14136
1.22164
1.04712
0.69808
0.52356
0.52356
1.04712
1.91972
1.57068
0.87260
1.57068
1.39616
3.83944
1.91972
0.17452
0.34904
0.00000
0.00000
0.00000
2.26876
sixteen
2.02578
4.41989
4.60405
4.41989
3.49908
4.05157
2.39411
1.84162
2.02578
2.02578
1.47330
2.20994
0.92081
1.28913
0.55249
1.47330
0.92081
0.36832
1.10497
1.10497
1.10497
0.92081
0.55249
0.73665
1.10497
0.55249
0.92081
0.73665
0.55249
0.36832
1.28913
1.10497
0.73665
1.28913
0.55249
0.92081
0.73665
0.36832
0.73665
0.73665
0.92081
0.92081
0.55249
1.28913
0.36832
0.18416
6.62983
4.78821
2.57827
1.84162
1.65746
3.13076
1.28913
1.28913
0.55249
0.36832
0.36832
0.00000
0.18416
1.65746
1.84162
4.78821
0.92081
0.36832
0.18416
0.36832
0.00000
0.18416
2.02578
seventeen
2.61044
3.61446
6.02410
6.62651
3.61446
2.00803
2.20884
2.40964
1.80723
1.40562
1.00402
1.40562
1.00402
1.20482
1.00402
1.40562
0.80321
0.40161
0.80321
1.40562
0.60241
0.60241
0.40161
1.20482
1.20482
0.20080
0.80321
1.20482
0.80321
0.40161
0.20080
1.20482
1.60643
0.80321
0.80321
0.80321
1.00402
0.80321
0.40161
0.60241
0.60241
0.00000
1.00402
0.80321
0.20080
1.00402
5.42169
4.81928
2.20884
2.40964
2.20884
0.60241
2.40964
1.60643
0.60241
1.00402
0.20080
0.20080
0.00000
1.40562
2.61044
2.61044
3.21285
1.60643
1.40562
0.00000
0.00000
0.00000
1.40562
eighteen
1.29870
3.37662
3.63636
3.89610
3.11688
3.37662
3.89610
2.33766
3.11688
0.25974
1.81818
1.03896
2.07792
1.55844
0.77922
1.29870
1.81818
1.03896
0.00000
1.03896
0.25974
0.77922
1.03896
1.29870
0.25974
0.25974
0.25974
0.77922
0.51948
1.55844
0.51948
0.51948
0.77922
0.77922
0.77922
0.77922
0.77922
1.29870
0.51948
0.51948
0.51948
1.03896
1.03896
0.77922
0.77922
0.51948
10.90909
4.41558
5.71429
4.67532
1.81818
1.03896
1.81818
1.03896
0.25974
0.51948
0.51948
0.00000
0.25974
0.00000
0.00000
0.25974
0.77922
3.11688
0.25974
0.51948
0.77922
0.00000
1.55844
twenty-four
1.75077
3.39856
3.70752
2.88363
2.26571
1.75077
1.54480
1.64779
0.72091
0.41195
0.72091
0.72091
0.72091
0.51493
0.92688
1.33883
0.61792
0.41195
1.13285
0.61792
1.02987
0.41195
0.72091
1.13285
0.82389
0.30896
0.30896
0.41195
0.41195
0.30896
0.61792
1.13285
0.82389
0.92688
0.51493
0.92688
0.20597
0.41195
0.72091
0.92688
0.30896
1.23584
0.92688
0.82389
0.82389
0.51493
8.44490
6.48816
5.87024
4.84037
3.29557
2.88363
1.64779
1.33883
2.16272
1.13285
0.92688
1.02987
0.72091
1.54480
1.95675
2.26571
0.92688
0.30896
0.61792
0.92688
0.61792
0.41195
4.11946
-------
time
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
32
34
36
38
40
42
44
46
48
50
52
54
56
58
60
90
120
150
180
210
240
270
300
330
360
390
420
450
480
510
540
570
600
630
660
690
720
>720
SIX
0.00000
0.11111
0.05556
0.16667
0.05556
0.00000
0.05556
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.05556
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.05556
0.05556
0.00000
0.05556
0.00000
0.05556
0.05556
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.22222
seven
0.05263
0.02632
0.07895
0.05263
0.00000
0.02632
0.00000
0.05263
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.02632
0.02632
0.00000
0.00000
0.00000
0.02632
0.02632
0.02632
0.05263
0.00000
0.02632
0.00000
0.05263
0.00000
0.02632
0.42105
Table 4a - Weekends
eight
0.00000
0.03279
0.01639
0.03279
0.06557
0.03279
0.01639
0.01639
0.01639
0.03279
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.01639
0.01639
0.01639
0.00000
0.00000
0.00000
0.00000
0.00000
0.03279
0.00000
0.01639
0.00000
0.00000
0.00000
0.00000
0.01639
0.01639
0.00000
0.00000
0.01639
0.00000
0.00000
0.01639
0.00000
0.00000
0.00000
0.00000
0.01639
0.00000
0.03279
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.01639
0.00000
0.00000
0.01639
0.04918
0.01639
0.01639
0.03279
0.00000
0.03279
0.34426
nine
0.03937
0.02362
0.05512
0.05512
0.00787
0.06299
0.00000
0.00787
0.01575
0.00787
0.00787
0.00787
0.02362
0.00787
0.00787
0.00000
0.01575
0.02362
0.00000
0.00787
0.00787
0.00000
0.02362
0.01575
0.00000
0.00000
0.00000
0.01575
0.00787
0.00000
0.00000
0.00787
0.00000
0.01575
0.00000
0.01575
0.00000
0.00000
0.00787
0.00000
0.00787
0.00000
0.00000
0.00000
0.00787
0.00787
0.03150
0.02362
0.00787
0.00000
0.00000
0.01575
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.01575
0.00787
0.00787
0.01575
0.02362
0.00787
0.03150
0.00000
0.00787
0.00787
0.27559
ten
0.00000
0.05147
0.05147
0.05147
0.03676
0.02206
0.03676
0.01471
0.02941
0.02206
0.00000
0.00000
0.01471
0.01471
0.02206
0.01471
0.00000
0.00735
0.01471
0.00000
0.00735
0.00000
0.00000
0.00000
0.00000
0.00000
0.00735
0.01471
0.00000
0.00000
0.00735
0.02206
0.03676
0.00735
0.00000
0.02941
0.00000
0.00000
0.00000
0.00000
0.00735
0.02206
0.00735
0.00735
0.00000
0.00735
0.04412
0.00735
0.00735
0.02206
0.00000
0.00000
0.00735
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.01471
0.00735
0.00735
0.00735
0.00735
0.00000
0.00000
0.01471
0.26471
eleven
0.02548
0.02548
0.01911
0.05096
0.02548
0.03822
0.00637
0.01911
0.01911
0.03185
0.00637
0.00637
0.02548
0.01274
0.01274
0.00000
0.00000
0.02548
0.00637
0.01274
0.00637
0.00637
0.01274
0.01274
0.00637
0.00637
0.00000
0.01274
0.00637
0.00637
0.02548
0.04459
0.00000
0.00637
0.00637
0.01274
0.00637
0.00000
0.00000
0.01911
0.01274
0.01274
0.00637
0.00000
0.00000
0.00637
0.08917
0.01911
0.02548
0.00000
0.00637
0.01274
0.00000
0.00000
0.00637
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00637
0.00637
0.01274
0.00637
0.00000
0.00000
0.20382
twelve
0.01500
0.05500
0.05500
0.03500
0.04000
0.04000
0.02500
0.04500
0.03500
0.01500
0.01500
0.03500
0.01500
0.00000
0.01500
0.01500
0.00500
0.01500
0.00500
0.01000
0.01500
0.01000
0.01000
0.00000
0.00000
0.01500
0.00500
0.00500
0.00500
0.00000
0.01000
0.00000
0.00500
0.00500
0.02500
0.00500
0.00000
0.02000
0.01500
0.00000
0.00000
0.00000
0.02000
0.00500
0.01000
0.00500
0.04000
0.03500
0.02500
0.02500
0.01000
0.00500
0.00000
0.00500
0.01000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00500
0.00000
0.00500
0.00000
0.00500
0.00000
0.00500
0.00000
0.14500
10
-------
time
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
32
34
36
38
40
42
44
46
48
50
52
54
56
58
60
90
120
150
180
210
240
270
300
330
360
390
420
450
480
510
540
570
600
630
660
690
720
>720
thirteen
0.00699
0.04196
0.05594
0.04196
0.04196
0.01399
0.03497
0.02098
0.00699
0.00699
0.01399
0.02797
0.01399
0.02797
0.00000
0.00699
0.00699
0.01399
0.01399
0.00699
0.00699
0.00000
0.01399
0.00699
0.00000
0.00000
0.00000
0.01399
0.01399
0.01399
0.01399
0.00000
0.02098
0.02098
0.01399
0.00000
0.01399
0.01399
0.01399
0.01399
0.01399
0.00699
0.01399
0.00000
0.00000
0.01399
0.06294
0.04895
0.01399
0.03497
0.02098
0.00699
0.00699
0.00699
0.00699
0.00699
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00699
0.12587
fourteen
0.03429
0.06286
0.04571
0.02857
0.05143
0.02286
0.01143
0.02857
0.02857
0.01714
0.02286
0.00000
0.01143
0.00571
0.00000
0.01714
0.01143
0.00571
0.00571
0.03429
0.01143
0.01143
0.00000
0.00571
0.01143
0.00571
0.01143
0.00571
0.00571
0.00571
0.00000
0.01143
0.01714
0.01143
0.00000
0.00000
0.01714
0.00000
0.00571
0.01143
0.00571
0.01714
0.00000
0.01714
0.00571
0.00000
0.08000
0.04571
0.04000
0.02286
0.00000
0.02857
0.00000
0.01143
0.00571
0.00000
0.00000
0.00000
0.00000
0.01143
0.00571
0.00000
0.00571
0.00000
0.00000
0.00000
0.00000
0.00571
0.09714
Table 4b - Weekends
fifteen
0.01379
0.06207
0.04828
0.06207
0.02759
0.03448
0.02069
0.01379
0.04138
0.03448
0.00690
0.01379
0.00000
0.00690
0.00000
0.00000
0.02069
0.01379
0.01379
0.00000
0.00690
0.01379
0.00000
0.00690
0.02069
0.00000
0.00690
0.00000
0.00690
0.00690
0.00000
0.00690
0.00690
0.00690
0.02759
0.00690
0.02069
0.00690
0.00690
0.02759
0.00690
0.00690
0.01379
0.00690
0.01379
0.00000
0.04138
0.04828
0.04138
0.03448
0.01379
0.02759
0.00690
0.01379
0.00000
0.00000
0.00000
0.00000
0.00000
0.00690
0.00690
0.00690
0.00000
0.00000
0.00000
0.00690
0.00000
0.00000
0.07586
sixteen
0.00704
0.04225
0.03521
0.04225
0.04225
0.04225
0.02817
0.03521
0.02817
0.02817
0.01408
0.00704
0.00704
0.02113
0.01408
0.00000
0.00000
0.00704
0.00704
0.02817
0.01408
0.00000
0.00704
0.01408
0.01408
0.02113
0.00000
0.00704
0.01408
0.00000
0.00704
0.02113
0.00704
0.00000
0.00704
0.04225
0.01408
0.00000
0.02817
0.00000
0.00000
0.00000
0.02113
0.00000
0.02113
0.00000
0.09155
0.04225
0.02817
0.05634
0.00000
0.02113
0.02113
0.01408
0.00704
0.00000
0.00000
0.00000
0.00000
0.01408
0.00704
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
seventeen
0.00758
0.02273
0.03788
0.04545
0.03030
0.01515
0.01515
0.03030
0.00758
0.03030
0.01515
0.00758
0.00000
0.00758
0.04545
0.03030
0.00758
0.03030
0.00758
0.00758
0.00758
0.01515
0.03030
0.00758
0.00758
0.00000
0.00000
0.00000
0.00000
0.00000
0.00000
0.01515
0.00758
0.00000
0.00000
0.02273
0.02273
0.01515
0.00758
0.00000
0.02273
0.00758
0.01515
0.00000
0.00000
0.01515
0.09091
0.06818
0.03030
0.03030
0.00000
0.01515
0.01515
0.01515
0.04545
0.03030
0.00000
0.01515
0.00000
0.00000
0.00000
0.00758
0.00758
0.00758
0.00000
0.00000
0.00000
0.00000
0.00000
eighteen
0.02542
0.04237
0.05085
0.03390
0.02542
0.00847
0.00000
0.03390
0.01695
0.01695
0.01695
0.01695
0.03390
0.00000
0.00847
0.00847
0.00000
0.01695
0.00000
0.01695
0.00847
0.00000
0.01695
0.00000
0.00847
0.00000
0.00000
0.00000
0.00847
0.00000
0.00847
0.01695
0.00847
0.00847
0.00000
0.00000
0.00000
0.02542
0.01695
0.00000
0.00000
0.00847
0.00000
0.02542
0.00000
0.00000
0.09322
0.11864
0.05932
0.01695
0.05085
0.01695
0.03390
0.01695
0.00847
0.00000
0.00000
0.00847
0.00000
0.00000
0.02542
0.00000
0.00847
0.00000
0.00000
0.00847
0.00000
0.00000
0.00000
twenty-four
0.01172
0.04297
0.05469
0.04688
0.05078
0.03125
0.02734
0.02344
0.00391
0.01563
0.01172
0.01953
0.00000
0.00000
0.00000
0.00000
0.01563
0.00391
0.00781
0.00391
0.00391
0.00781
0.00000
0.00391
0.00781
0.00391
0.00000
0.00000
0.00000
0.00781
0.00000
0.00781
0.00000
0.00000
0.00391
0.01172
0.00391
0.00391
0.00391
0.00781
0.00391
0.01563
0.00391
0.00000
0.00391
0.00391
0.08984
0.05469
0.05469
0.06250
0.05078
0.02734
0.03125
0.04688
0.00391
0.00781
0.01563
0.02344
0.00000
0.00391
0.01953
0.00391
0.00391
0.00781
0.00781
0.00000
0.00391
0.00000
0.00000
11
-------
Figure 1
Cumulative Soak Length Distribution for Selected Hourly Groups
(Soaks are Prior to Vehicle Start)
100 200 300 400 500
Soak Time (Minutes)
600
700
800
12
-------
COMMENTS
Comments on this report and its proposed use in MOBILE6 should be sent to the attention of the
author, and submitted electronically to mobile@epamail.epa.gov, or by fax to (313)741-7939, or by
mail to MOBILE6 Review Comments, US EPA Assessment and Modeling Division, 2565 Plymouth
Road, Ann Arbor MI 48105. Electronic submission of comments is preferred, since we will make
any comments available on our web site. In your comments, please note clearly the document that
you are commenting on including the report title and the code number listed. Please be sure to
include your name, address, affiliation, and any other pertinent information.
13
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