NATIONAL MOBILE2
VARIABLE ESTIMATES
ENERGY AND ENVIRONMENTAL ANALYSIS, INC.
1111 North 19th Street
Arlington, Virginia 22209
(703)528-1900
-------
NATIONAL MOBILE2
VARIABLE ESTIMATES
EPA Contract No. 68-03-2888
Prepared for:
TEST AND EVALUATION BRANCH
EMISSION CONTROL TECHNOLOGY DIVISION
OFFICE OF MOBILE SOURCE AIR POLLUTION CONTROL
OFFICE OF AIR, NOISE AND RADIATION
U.S. ENVIRONMENTAL PROTECTION AGENCY
ANN ARBOR, MICHIGAN
Prepared by:
ENERGY AND ENVIRONMENTAL ANALYSIS, INC.
1111 North 19th Street
Arlington, Virginia 22209
November 1980
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TABLE OF CONTENTS
Page
1. INTRODUCTION. 1-1
2. MILEAGE ACCUMULATION BY AGE 2-1
3. VEHICLE REGISTRATIONS BY AGE 3-1
4. AVERAGE TRIPS PER DAY 4-1
5. VEHICLE MILES PER DAY 5-1
6. VEHICLE MILES TRAVELED 6-1
7. FRACTION OF VEHICLES WITH AIR CONDITIONING .7-1
8. AMBIENT CONDITIONS 8-1
9. VMT PERCENTAGE IN HOT/COLD STARTS 9-1
10. EXTRA LOAD AND TRAILER TOWING TRIPS 10-1
11. SPEED BY ROAD TYPE 11-1
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1. INTRODUCTION
The purpose of this report is to describe work performed by EEA, Inc.
for task order No. 5 of EPA Contract No. 68-03-2888. The objective of
this task order was to develop national estimates of 12 MOBILE2 input
variables for use in the MOBILE2 computer program and its supporting
documentation. This report both presents the national estimates for
each of these variables and explains the techniques used to derive them.
In most cases, the estimates included in this report reflect national
data inclusive of both urban and rural areas. Where only urban data
were available for making national estimates, this is specifically noted
in the report.
Table 1-1 shows the MOBILE2 input variables and vehicle types discussed
in this report. The vehicle type abbreviations shown at the bottom of
the table are those used throughout the report. The report is organized
so that estimation techniques for each variable are presented in separate
sections. The only exception to this is that variables 7-9 are combined
in one section labeled "ambient conditions." Within each section,
estimation techniques are presented separately for each vehicle type.
1-1
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TABLE 1-1
MOBILE2 INPUT VARIABLES
Variables
1. Mileage accumulation by age
2. Vehicle registrations by age
3. Average trips/day
4. Vehicle miles/day
5. Total VMT fractions
6. Fraction of vehicles with air
conditioning by model year
7. Air conditioning usage from
ambient condition variables
8. Average temperature
9. Average humidity levels
(grains of water/Ib of dry air)
10. Average percent VMT in cold/hot starts
for catalyst and non-catalyst vehicles
11. Fraction of trips/day with either
extra load or trailer towing
12. Speed
Vehicle
Type*
All
All
All
All
All
All except MC,
HDGV, and HDDV
**
**
**
All
All except MC,
HDGV, and HDDV
All
* LDGV: Light-Duty Gasoline-Powered Vehicles
LDDV: Light-Duty Diesel-Powered Vehicles
LDGT1: Light-Duty Gasoline-Powered Trucks (<6001 Ibs GVW)
LDGT2: Light-Duty Gasoline-Powered Trucks (>6000 Ibs and <8501 Ibs GVW)
LDDT: Light-Duty Diesel-Powered Trucks (<8501 Ibs GVW)
HDGV: Heavy-Duty Gasoline-Powered Vehicle (>8500 Ibs GVW)
HDDV: Heavy-Duty Diesel-Powered Vehicle (>8500 Ibs GVW)
MC: Motorcycles
**Independent of vehicle type
1-2
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2. MILEAGE ACCUMULATION BY AGE
Estimates of national average mileage accumulation by age can be taken
directly from Section 2 of Techniques for Estimating MOBILE2 Variables.
The relevant tables from that section are shown in the following three
pages.
Table 2-1 shows estimated annual miles traveled and mileage accumulation
by age for light-duty vehicles. This table applies to both light-duty
gasoline and diesel-powered vehicles. Table 2-2 presents mileage accumu-
lation by age data for the five truck categories used in MOBILE2.
Mileage accumulation by age information is presented in Table 2-3 for
motorcycles.
2-1
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TABLE 2-1
ESTIMATED ANNUAL MILES TRAVELED AND
MILEAGE ACCUMULATION BY AGE
FOR LIGHT-DUTY VEHICLES
NATIONAL AVERAGES
Age Estimated Annual Miles Accumulated Miles
^^•^•M
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
14,436
13,903
13,371
12,838
12,306
11,773
11,240
10,708
10,176
9,643
9,110
8,577
8,045
7,513
6,980
6,447
5,927
5,382
4,850
4,317
14,436
28,339
41,710
54,548
66,854
78,627
89,867
100,575
110,751
120,394
129,504
138,081
146,126
153,639
160,619
167,066
172,993
178,375
183,225
187,542
Source: U.S. Department of Transportation, National Highway Traffic
Safety Administration, 1980.
2-2
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TABLE 2-2
MILEAGE ACCUMULATION BY AGE FOR TRUCK CATEGORIES
NATIONAL AVERAGES
Vehicle
Age
' 1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
LDGT1
15,610
14,049
12,488
11,239
10,147
9,366
8,585
7,961
7,493
7,025
6,556
6,244
5,932
5,463
5,151
4,996
4,683
4,370
4,371
4,371
LDGT2
15,800
14,220
12,640
11,376
10,270
9,480
8,690
8,058
7,584
7,110
6,636
6,320
6,004
5,510
5,234
5,056
. 4,740
4,424
4,424
4,424
HDGV
20,980
18,882
17,204
15,525
14,057
12,587
11,329
10,280
9,441
8,602
7,973
7,343
6,713
6,294
5,875
5,454
5,245
5,036
5,034
5,034
LDDT
15,705
15,077
14,605
13,978
13,035
12,093
10,993
9,738
9,266
7,381
6,753
6,125
5,491
5,031
4,555
4,240
3,769
3,141
3,141
3,141
HDDV
70,418
66,897
60,560
54,221
47,885
43,659
39,434
36,618
34,504
33,096
32,392
31,689
30,953
29,606
27,463
24,646
20,422
17,604
17,605
. 17,605
Source: Jambekar and Johnson, 1977.
2-3
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TABLE 2-3
NATIONAL AVERAGE MILES PER YEAR BY AGE AND MILEAGE
ACCUMULATION BY AGE FOR MOTORCYCLES
Age
1
2
3
4
5
6
7
8
9
10
11
12
13
Average Miles*
Per Year
4067
2845
2072
1569
1180
777
630
387
243
162
162
162
162
Average
Mileage
Accumulation
4067
6912
8984
10553
11733
12510
13140
13527
13770
13932
14094
14256
14418
Mean number of months per year 7
Median number of months per year 7
* Weighted by the mix of on-road and dual purpose motorcycles registered
in 1978.
Source: Personal Communication with Pam Amette, Motorcycle Industry
Council, Inc., and the 1979 Motorcycle Statistical Annual
2-4
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3. VEHICLE REGISTRATIONS BY AGE
Estimates of national vehicle registrations by age for the eight MOBILE2
vehicle type categories are presented in this section. Much of the data
used in the tables in this section are taken directly from Section 3 of
Techniques For Estimating MOBILE2 Variables. National light-duty vehicle
registrations by model year are shown in Table 3-1. Both light-duty
gasoline and diesel-powered vehicle registrations are accounted for in
these totals. LDGV and LDDV registrations are estimated using the fleet
sales fractions listed in Table 3-2. Tables 3-3 and 3-4 show how these
sales fractions are used to estimate national LDGV and LDDV registrations
by model year in 1978.
Tables 3-5, 3-6 and 3-7 show how sales and scrappage rate information
from Section 3 of the Techniques report can be used to estimate registra-
tions by model year for LDGT1, LDGT2, and LDDT, respectively. In order
to apply the diesel and gasoline sales fractions in Table 3-2 (which are
used in MOBILE2) to estimate LDGT1 and LDDT registrations, the estimated
registrations by model year in Tables 3-5 and 3-7 are summed. Table 3-8
lists these totals. Tables 3-9 and 3-10 then show how the Table 3-2
dieselization rates are used to estimate national LDGT1 and LDDT registra-
tions by age.
Table 3-11 shows the calculation of national vehicle registration frac-
tions for heavy-duty gasoline-powered trucks. Heavy-duty diesel-powered
truck registrations are calculated in a similar manner as shown in Table
3-12. Motorcycle registration fractions by age are listed in Table 3-13.
3-1
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TABLE 3-1
LIGHT-DUTY VEHICLE REGISTRATIONS BY MODEL YEAR MIX
NATIONAL TOTALS IN 1978
Percentage of
Total LDV
Registrations
.0721
.1009
.0921
.0708
.0916
.1026
.0888
.0712
.0659
.0591
.0478
.0349
.0300
.0230
.0150
.0099
.0055
.0025
.0017
.0145
Model
Year
Mix
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
TOTAL
Estimated
Vehicle
Registrations
7,426,000
10,382,000
9,483,000
7,291,000
9,431,000
10,559,000
9,140,000
7,326,000
6,784,000
6,087,000
4,917,000
3,589,000
3,093,000
2,369,000
1,545,000
1,021,000
571,000
256,000
180,000
1,489,000
102,939,000
SOURCE: MVMA, Motor Vehicle Facts and Figures 1979.
3-2
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TABLE 3-2
FLEET SALES FRACTIONS* FOR 49-STATE
LIGHT-DUTY VEHICLES AND LIGHT-DUTY TRUCKS
Model
Years
PRE-1975
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991+
LDGV
1.000
.998
.997
.995
.991
.972
.966
.953
.925
.911
.905
.886
.862
.835
.824
.813
.803
.800
LDDV
0.0
.002
.003
.005
.009
.028
.034
.047
.075
.089
.095
.114
.138
.165
.176
.187'
.197
.200
LDGT1
1.000
1.000
1.000
1.000
.991
.972
.966
.953
.925
.911
.905
.886
.862
.835
.824
.813
.803
.800
LDDT
0.0
0.0
0.0
0.0
.009
.028
.034
.047
.075
.089
.095
.114
.138
.165
.176
.187
.197
.200
* The estimated fraction of the light-duty vehicle (truck) fleet which
is diesel-powered is taken from Murrell et al. (1980) for 1975-1980
model years and U.S. EPA (1979) for 1981-1991 model years.
3-3
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TABLE 3-3 .
LIGHT-DUTY GASOLINE-POWERED VEHICLES
ESTIMATED VEHICLE REGISTRATIONS
NATIONAL TOTALS IN 1978
Model Year
Mix
(Age)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20+
LDGV & LDDV
Estimated
Vehicle
Registrations
7,426,000
10,382,000
9,483,000
7,291,000
9,431,000
10,559,000
9,140,000
7,326,000
6,784,000 -
6,087,000
4,917,000
3,589,000
3,093,000
2,369,000
1,545,000
1,021,000
571,000
256,000
180,000
1,489,000
102,939,000
Fleet Sales*
Fraction
for LDGV
.991
.995
.997
.998
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
Estimated
LDGV
Registrations
7,359,166
10,330,090
9,454,551
7,276,418
9,431,000
10,559,000
9,140,000
7,326,000
6,784,000
6,087,000
4,917,000
3,589,000
3,093,000
2,369,000
1,545,000
1,021,000
571,000
256,000
180.000
1,489,000
102,780,000
Registration
Fractions
.072
.101
.092
.071
.092
.103
.089
.071
.066
.059
.048
.035
.030
.023
.015
.010
.006
.002
.002
.014
* The estimated fraction of the light-duty vehicle fleet which is
diesel-powered is taken from Murrell et al. (1980).
3-4
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TABLE 3-4
LIGHT-DUTY DIESEL-POWERED VEHICLES
ESTIMATED VEHICLE REGISTRATIONS
NATIONAL TOTALS IN 1978
Model Year
Mix
(Age)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20+
LDGV & LDDV
Estimated
Vehicle
Registrations
7,426,000
10,382,000
9,483,000
7,291,000
9,431,000
10,559,000 '
9,140,000
7,326,000
6,784,000
6,087,000
4,917,000
3,589,000
3,093,000
2,369,000
1,545,000
1,021,000
571,000
256,000
180,000
1,489,000
Fleet Sales* Estimated
Fraction LDDV
for LDDV Registrations
0.009 66,834
.005 51,910
.003 28,449
.002 14,582
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Registration
Fractions
.413
.321
.176
.090
161,775
* The estimated fraction of the light-duty vehicle fleet which is
diesel-powered is taken from Murrell et al. (1980).
3-5
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TABLE 3-5
CALCULATION OF NATIONAL VEHICLE REGISTRATIONS
FOR LIGHT-DUTY GASOLINE TRUCKS (0-6000 LBS. GVW)
Model
Year .
1978
1977
1976
1975
1974
1973
1972
1971
1970
1969
1968
1967
1966
1965
1964
1963
1962
1961
1960
1959
1958
* From
** From
Vehicle
Age
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20+
Table 3-10
Table 3-7
Sales*
0-6000 Ibs.
1,211,899
1,251,449
1,181,906
897,292
1,409,586 .
1,639,663
1,339,226
1,133,911
895,238
1,052,057
1,069,389
836,429
957,168
987,503
839,808
765,114
610,600
524,135
534,431
461,885
1-SR**
10,000 Ibs.
1.00
.97
.93
.88
.83
.78
.73
.68
.63
.59
.55
.51
.47
.43
.40
.36
.32
.28
.25
.21
346,209 .18
of Techniques For Estimating MOBILE2
of Techniques For
Estimating MOBILE2
Estimated
Registrations
1,211,899
1,213,906
1,099,173
789,617
1,169,956
1,278,937
977,635
771,059
564,000
620,714
588,164
426,579
449,869
424,626
335,923
275,441
195,392
146,758
133,608
96,996
62,318
12,832,570
Variables, 1980.
Variables, 1980.
3-6
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TABLE 3-6
CALCULATION OF NATIONAL VEHICLE REGISTRATION FRACTIONS
FOR LIGHT-DUTY GASOLINE TRUCKS (6000-8500 LBS. GVW)
Model
Year
1978
1977
1976
1975
1974
1973
1972
1971
1970
1969
1968
1967
1966
1965
1964
1963
1962
1961
1960
1959
1958
* From
** From
Vehicle
Age
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
•17
18
19
20+
Table 3-10
Table 3-7
Sales* 1-SR** Estimated Registration
6000-8500 Ibs. 10,000 Ibs. Registrations Fractions
1,389,944
1,211,845
947,790
625,731
391,225
407,337
303,986
247,485
208,414
192,945
178,527
124,803
117,075
105,622
76,305
86,007
79,134
57,597
58,283
65,562
47,694
of Techniques
of Techniques
1.00 1,
.97 1,
.93
.88
.83
.78
.73
.68
.63
.59
.55
.51
.47
.43
.40
.36
.32
.28
.25
.21
.18
5,
For Estimating MOBILE2
For Estimating MOBILE2
389,944
175,490
881,445
550,643
324,717
317,723
221,910
168,290
131,301
113,838
98,190
63,650
55,025
45,417
30,522
30,963
25,323
16,127
14,571
13,768
8,585
677,442
Variables,
Variables,
.245
.207
.155
.097
.057
.056
.039
.030
.023
.020
.017
.011
.010
.008
.005
.005
.004
.003
.003
.004
1980.
1980.
3-7
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TABLE 3-7
CALCULATION OF NATIONAL VEHICLE REGISTRATIONS
FOR LIGHT-DUTY DIESEL TRUCKS (0-8500 LBS. GVW)
Model
Year
1978
1977
1976
1975
1974
1973
1972
1971
1970
1969
1968
1967
1966
1965
1964
1963
1962
1961
1960
1959
* From
** From
Vehicle
Age
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20+
Table 3-11
Table 3-7
Sales*
<8500 Ibs
34,751
2,924
1,303
1
0
0
0
70
233
445
714
801
431
494
994
162
75
9
0
0
of Techniques
of Techniques
1-SR**
<10,000 Ibs.
1.00
.97
.93
.88
.83
.78
.73
.68
.63
.59
.55
.51
.47
.43
.40
.36
.32
.28
.25
.21
For Estimating MOBILE2
For Estimating MOBILE2
Estimated
Registrations
34,751
2,836
1,212
1
0
0
0
48
147
263
393
409
203
212
398
58
24
3
0
0
40,958
Variables, 1980.
Variables, 1980.
3-8
-------
TABLE 3-8
LIGHT-DUTY GASOLINE TRUCKS (0-6000 LBS. GVW) AND
LIGHT-DUTY DIESEL TRUCKS (0-8500 LBS. GVW)
COMBINED VEHICLE REGISTRATIONS
NATIONAL TOTALS IN 1978
Model Year Estimated
Mix Vehicle
(Age) Registrations
1 1,246,650
2 1,216,742
3 1,100,385
4 789,618
5 1,169,956
6 1,278,937
7 977,635
8 771,107
9 564,147
10 620,977
11 588,557
12 426,988
13 450,072
14 424,838
15 336,321
16 275,499
17 195,416
18 146,761
19 133,608
20+ 159,314
3-9
-------
TABLE 3-9
LIGHT-DUTY GASOLINE TRUCKS (0-6000 LBS. GVW)
ESTIMATED VEHICLE REGISTRATIONS
NATIONAL TOTALS IN 1978
Model Year
Mix
(Age)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20+
LDGT & LDDT
Estimated
Vehicle
Registrations
1,246,650
1,216,742
1,100,385
789,618
1,169,956
1,278,937
977,635
771,107
564,147
620,977
588,557
426,988
450,072
424,838
336,321
275,499
195,416
146,761
133,608
159,314
Fleet Sales*
Fraction
for LDGT1
0.991
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
Estimated
LDGT1
Registrations
1,235,430
1,216,742
1,100,385
789,618
1,169,956
1,278,937
977,635
771,107
564,147
620,977
588,557
426,988
450,072
424,838
336,321
275,499
195,416
146,761
133,608
159,314
12,862,308
Registrations
Fractions
.096
.095
.086
.061
.091
.099
.076
.060
.044
.048
.046
.033
.035
.033
.026
.021
.015
.011
.010
.012
* The estimated fraction of the light-duty truck fleet which is
diesel-powered is taken from Murrell et al. (1980).
3-10
-------
TABLE 3-10
LIGHT-DUTY DIESEL TRUCKS (0-8500 LBS. GVW)
ESTIMATED VEHICLE REGISTRATIONS
NATIONAL TOTALS IN 1978
Model Year
Mix
(Age)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
• 18
19
20+
LDGT1 & LDDT
Estimated
Vehicle
Registrations
1,246,650
1,216,742
1,100,385
789,618
1,169,956
1,278,937
977,635
771,107
564,147
620,977
588,557
426,988
450,072
424,838
336,321
275,499
195,416
146,761
133,608
159,314
Fleet Sales* Estimated
Fraction LDDT
for LDDT Registrations
0.009 11,220
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Registration
Fractions
1.000
* The estimated fraction of the light-duty truck fleet which is
diesel-powered is taken from Murrell et al. (1980).
3-11
-------
TABLE 3-11
CALCULATION OF NATIONAL VEHICLE REGISTRATION FRACTIONS
FOR HEAVY-DUTY GASOLINE TRUCKS ( 8500 LBS GVW)
(1-Scrappage)** Estimated
Model
Year
1978
1977
1976
1975
1974
1973
1972
1971
1970
1969
1968
1967
1966
1965
1964
1963
1962
1961
1960
1959
1958
Sales*
8501-10,000 Ib
388,781
368,078
318,230
227,578
269,087
305,873
245,537
206,415
164,913
186,035
186,470
143,632
160,519
163,340
136,891
127,189
103,064
86,926
88,566
78,814
58,859
Rate
<10,000 Ib
1.00
.97
.93
.88
.83
.78
.73
.68
.63
.59
.55
.51
.47
.43
.40
.36
.32
.28
.25
.21
.18
Registrations
(8501-10,000 Ib)
388,781
357,036
295,954
200,269
223,342
238,581
17^,242
140,362
103,895
109,761
102,559
73,252
75,444
70,236
54,756
45,788
32,980
24,339
22,142
16,551
10,595
Total
(1-Scrappage)** Estimated
Sales*
< 10, 000 Ib
205,109
182,089
178,955
179,551
255,026
281,781
275,994
225,009
205,303
248,437
247,282
238,774
254,381
257,012
241,490
261,227
246,729
231,050
265,006
301,055
220,456
Rate
>10,000 Ib
1.00
.95
.88
.79
.69
.61
.54
.48
.43
.38
.33
.29
.25
.20
.17
.14
.11
.08
.06
.04
.03
Registrations
(>10,000 Ib)
205,109
172,985
157,480
141,845
175,968
171,886
149,037
108,004
88,280
94,406
81,603
69,244
63,595
51,402
41,053
36,572
27,140
18,484
15 , 900
12,042
6,614
Estimated
Registrations
(>8500 Ib)
593,890
530,021
453,434
342,114
399,310
410,467
328,279
248,366
192,175
204,167
184,162
142,496
139,039
121,638
95,809
82,360
60,120
42,823
38,042
28,593
17,209
Registration
Fractions
.128
.114
.097
.074
.086
.088
.071
.053
.041
.044
.040
.031
.030
.026
.021
.018
.013
.009
.008
.006
.004
4,654,514
* From Table 3-10 of Techniques For Estimating MOBILE2 Variables, 1980.
** From Table 3-7 of Techniques For Estimating MOBILE2 Variables, 1980.
1.002
-------
TABLE 3-12
CALCULATION OF NATIONAL VEHICLE RfiEISTRATIOtTFRACTIONS
FOR HEAVY-DUTY DIESEL TRUCKS ( 8500 LBS. GVW)
CO
I
u>
Model
Year
1978
1977
1976
1975
1974
1973
1972
1971
1970
1969
1968
1967
1966
1965
1964
1963
1962
1961
1960
1959
1958
1957
* From
Vehicle Sales*
Age 8501-10,000 Ib.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20+
Table
840
437
195
0
0
0
0
11
35
67
107
120
64
74
148
24
11
0
0
0
3-11 of Techniques
Estimated
1-SR** Registrations Sales* 1-SR**
<10,000 Ib. (8501-10,000 Ib.) >10,000 Ib. >10,000 Ib.
1.00
.97
.93
.88
.83
.78
.73
.68
.63
.59
.55
.51
.47
.43
.40
.36
.32
.28
.25
.21
For Estimating
840
424
181
0
0
0
0
7
22
40
59
61
30
32
59
9
4
0
0
0
MOBILE2
184,324
162,198
105,718
72,604
144,702
152,159
129,628
101,407
91,533
101,191
82,602
69,879
85,054
71,789
56,037
47,025
38,378
24,931
28.186
32,741
22,884
21.607
Variables, 1980.
1.00
.91
.84
.77
.71
.64
.58
.53
.48
.43
.39
.35
.31
.28
.24
.21
.19
.16
.14
.11
.09
.07
Total
Estimated Estimated
Registrations Registrations Registration
(>10,000 Ib.) (>8500 Ib.) Fractions
184,324
147,600
88.803
55,905
102,738
97,382
75,184
53,746
43,936
43,512
32,215
24.458
26.367
20,101
13,449
9.875
7,292
3.989
3,946
3.602
2.060
1,512
185,164
148,024
88,984
55.905
102,738
97,382
75.184
53,753
43,958
43,552
32,274
24,519
26,397
20.133
13,508
9,884
7,296
3,989
3,946
3,602
2,060
1,512
1,043,764
.177
.142
.085
.054
.098
.093
.072
.051
.042
.042
.031
.023
.025
.019
.013
.009
.007
.004
.004
.007
** From Table 3-7 of Techniques For Estimating HOBILE2 Variables, 1980.
-------
TABLE 3-13
MOTORCYCLE REGISTRATIONS ~ PERCENTAGE BY AGE
NATIONAL AVERAGE
Fraction of*
Motorcycle Age Total
(years) Registrations
1 .133
2 .145
3 .138
4 .116
5 .123
6 .114
7 .069
8 .044
9 .024
10 .009
11+ .085
1.000
*Based on the estimated population in use in 1978.
Source: Motorcycle Industry Council, Inc., 1979
3-14
-------
4. AVERAGE TRIPS PER DAY
National average estimates of the number of trips per day per vehicle
can be determined from Section 7 of Techniques for Estimating MOBILE2
Variables. Estimates are presented below for each vehicle type.
Light-Duty Vehicles
Table 7-1 in the Techniques report shows the trip rate per household by
location and population. The average trip rate per household is 4.3 for
unincorporated areas and 3.6 for incorporated areas. Weighting these
two trip rates by the respective U.S. population in 1970 (8.85% of the
1970 population lived in unincorporated places, the remainder in incorpor-
ated places), gives an average U.S. trip rate per household of 3.66 per
day. This should be divided by the average number of cars per household
to determine the average number of trips per day per vehicle. According
to the NPTS, the average number of cars per household is 1.2. Therefore,
the average number of trips per day per vehicle is 3.05. This number
should apply to both light-duty gasoline and diesel-powered vehicles.
Light-Duty Trucks
Although no specific data on light-duty truck travel are available from
the 1972 NPTS, it is assumed here that the 3.05 trips per day estimate
for light-duty vehicles also applies to light-duty trucks. All light-duty
truck classes (LDGT1, LDGT2, LDDT) are assumed to have the same tripmaking
patterns.
Heavy-Duty Vehicles
Using New York and Los Angeles data (France, 1978) from an EPA Technical
Report, the average number of trips/day for heavy-duty vehicles is 6.88
for HDGV and 6.65 for HDDV. (See Table 7-6 in the Techniques report).
4-1
-------
Motorcycles
The national average motorcycle trips per day are estimated using Table 7-7
in the Techniques report. The relevant portion of that table is shown
below.
Motorcycle
Trip Purpose
Commuting:
Work
School
Non-C ommut ing:
TOTAL
Percentage of Total
Registered Motorcycles Used
For This Purpose
36
10
100
Median Number of
One Way
Trips/Day
0.7
0.6
1.04
Trips/Day
Per Trip
Purpose
.25
.06
1.04
1.35
Therefore, the average number of trips per day per registered motorcycle
is 1.35.
4-2
-------
5. VEHICLE MILES PER DAY
National average estimates of vehicle miles traveled per day by vehicle
type are shown in Table 5-1. The calculations used to derive these
estimates are illustrated in Tables 5-2 through 5-8, one for each vehicle
type. Miles per day estimates for all vehicle categories use estimated
nationwide registrations in 1978 and average mileage accumulation by age
information to compute an average VMT per year number. After this
number is converted to VMT per day, it is divided by the total number of
registered vehicles in 1978 to derive a per vehicle estimate. All
vehicle types are assumed to travel 365 days per year except motorcycles.
Motorcycles are assumed to drive 7 months or 210 days per year. The
calculation of average miles per day by vehicle type is summarized in
Table 5-9 for all vehicle types except light-duty vehicles.
5-1
-------
TABLE 5-1
NATIONAL AVERAGE
MILES TRAVELED PER DAY BY VEHICLE TYPE
Vehicle Type Miles/Day
LDGV 31.1
LDDV 31.1
LDGT 1 26.3
LDGT 2 33.8
LDDT . 29.8
HDGV 36.7
HDDV 138.1
MC 8.3
5-2
-------
TABLE 5-2
LDGV AND LDDV COMBINED
CALCULATION OF NATIONAL AVERAGE ANNUAL MILES DRIVEN
Model Estimated* „
Year Registrations (x 10 )
1978
1977
1976
1975
1974
1973
1972
1971
1970
1969
1968
1967
1966
1965
1964
1963
1962
1961
1960
1959
* From Table 3-2
** From Table 2-1
7,426
10,382
9,483
7,291
9,431
10,559
9,140
7,326
6,784
6,087
4,917
3,589
3,093
2,369
1,545'
1,021
571
256
180
1,489
102,939
of Techniques
of Techniques
i Annual Mileage**
14,436
13,903
13,371
12,838
12,306
11,773
11,240
10,708
10,176
9,643
9,110
8,577
8,045
7,513
6,980
6,447
5,927
5,382
4,850
4,317
For Estimating MOBILE2
For Estimating MOBILE2
VMT by
Model Year
(x 108)
1,072.0
1,443.4
1,268.0
936.0
1,160.6
1,243.1
1,027.3
784.5
690.3
587.0
447.9
307.8
248.8
178.0
107.8
65.8
33,8
13.8
8.7
64.3
11,688.9
Variables.
Variab les .
5-3
-------
TABLE 5-3
LIGHT-DUTY GASOLINE TRUCKS (0-6000 LBS. GVW)
CALCULATION OF NATIONAL AVERAGE ANNUAL MILES DRIVEN
Model
Year
1978
1977
1976
1975
1974
1973
1972
1971
1970
1969
1968
1967
1966
1965
1964
1963
1962
1961
1960
1959
1959
LDGT1 + LDDT
Estimated
Registrations
(From Table 3-8) .
1,246,650
1,216,742
1,100,385
789,618
1,169,956
1,278,937
977,635
771,107
564,147
620,977
588,557
426,988
450,072
424,838
336,321
275,499
195,416
146,761
133,608
96,996
62,318
12,873,528
Annual Mileage*
15,610
14,049
12,488
11,239
10,147
9,366
8,585
7,961
7,493
7,025
6,556
6,244
5,932
5,463
5,151
4,996
4,683
4,370
4,371
4,371
4,371
VMT by
Model Xear
(x 108)
194.6
170.9
137.4
88.7
118.7
119.8
83.9
61.4
42.3
43.6
38.6
26.7
26.7
23.2
17.3
13.8
9.2
6.4
5.8
4.2
2.7
1,235.9
* From Table 2-4 of Techniques For Estimating MOBILE2 Variables.
5-4
-------
TABLE 5-4
LIGHT-DUTY DIESEL TRUCKS (0-8500 LBS. GVW)
CALCULATION OF NATIONAL AVERAGE ANNUAL MILES DRIVEN
Model
Year
1978
1977
1976
1975
1974
1973
1972
1971
1970
1969
1968
1967
1966
1965
1964
1963
1962
1961
1960
1959
1958
LDGT1 + LDDT
Estimated
Registrations
(From Table 3-8)
1,246,650
1,216,742
1,100,385
789,618
1,169,956
1,278,937
977,635
771,107
564,147
620,977
588,557
426,988
450,072
424,838
336,321
275,499
195,416
146,761
133,608
96 , 996
62,318
12,873,528
Annual Mileage*
15,705
15,077
14,605
13,978
13,035
12,093
10,993
9,738
9,266
7,381
6,753
6,125
5,497
5,031
4,555
4,240
3,769
3,141
3,141
3,141
3,141
VMT by
Model Year
(x 10 )
195.8
183.4
160.7
110.4
152.5
154.7
107.5
75.1
44.3
41.9
36.0
23.5
22.6
19.4
14.3
10.4
6.1
4.6
4.2
3.0
2.0
1,398.4
* From Table 2-4 of Techniques For Estimating MOBILE2 Variables.
5-5
-------
TABLE 5-5
LIGHT-DUTY GASOLINE TRUCKS (6001-8500 LBS. GVW)
CALCULATION OF NATIONAL AVERAGE ANNUAL MILES DRIVEN
VMT by
Model
Year
1978
1977
1976
1975
1974
1973
1972
1971
1970
1969
1968
1967
1966
1965
1964
1963
1962
1961
1960
1959
1958
Estimated
Registrations
1,389,944
1,175,490
881,445
550,643
324,717
317,723
221,910
168,290
131,301
113,838
98,190
63,650
55,025
45,417
30,522
30,963
25,323
16,127
14,571
13,768
8,585
Annual
Mileage
15,800
14,220
12,640
11,376
10,270
9,480
8,690
8,058
7,584
7,110
6,636
6,320
6,004
5,510
5,234
5,056
4,740
4,424
4,424
4,424
4,424
Model gear
219.61
167.15
111.41
62.64
33.35
30.12
19.28
13.56
9.96
8.09
6.52
4.02
3.30
2.50
1.60
1.57
1.20
0.71
0.64
0.61
0.38
TOTAL LDGT2 VMT per year 698.22
5-6
-------
TABLE 5-6
HEAVY DUTY GASOLINE VEHICLES
CALCULATION OF NATIONAL AVERAGE ANNUAL MILES DRIVEN
VMT by
Model Yr
(x 10*)
12.46
10.01
7.80
5.31
5.61
5.17
3.72
2.55
1.81
1.76
1.47
1.05
.93
.77
.56
.45
.32
.22
.19
.14
.09
62.39
* From Table 2-4 of Techniques For Estimating MOBILE2 Variables, 1980.
Calendar
Year
1978
1977
1976
1975
1974
1973
1972
1971
1970
1969
1968
1967
1966
1965
1964
1963
1962
1961
1960
1959
1958
Total Heavy
Estimated
Registrations
593,890
530,021
453,434
342,114
399,310
410,467
328,279
248,366
192,175
204,167
184,162
142,496
139,039
121,638
95,809
82,360
60,120
42,823
38,042
28,593
17,209
Duty Gasoline Vehicle
Annual Mil*
20,980
18,882
17,204
15,525
14,057
12,587
11,329
10,280
9,441
8,602
7,973
7,343
6,713
6,294
5,875
5,454
5,245
5,036
5,034
5,034
5,034
VMT 'per Year
5-7
-------
TABLE 5-7
HEAVY-DUTY DIESEL VEHICLES
CALCULATION OF NATIONAL AVERAGE ANNUAL MILES DRIVEN
Calendar
Year
1978
1977
1976
1975
1974
1973
1972
1971
1970
1969
1968
1967
1966
1965
1964
1963
1962
1961
1960
1959
Estimated
Registrations
185,164
148,024
88,984
55,905
102,738
97,382
75,184
53,753
43,958
43,552
32,274
24,519
26,397
20,133
13,508
9,884
7,296
3,989
3,946
3,602
Annual Mileage*
70,418
66,897
60,560
54,221
47,885
43,659
39,434
36,618
34,504
33,096
32,392
31,689
30,953
29,606
27,463
24,646
20,422
17,605
17,604
17,604
VMT x 109
by Model Year
13.039
9.902
5.389
3.031
4.920
4.252
2.965
1.968
1.517
1.441
1.045
0.777
0.817
0.596
0.371
0.244
0.149
0.070
0.069
0.063
Total Heavy-Duty Diesel Vehicle VMT per Year 52.625
* From Table 2-4 of Techniques For Estimating MOBILE2 Variables, 1980.
5-8
-------
TABLE 5-8
MOTORCYCLES
CALCULATION OF AVERAGE ANNUAL MILES DRIVEN
Year
Sold
New
1978
1977
1976
1975
1974
1973
1972
1971
1970
1969
1968+
Estimated*
Population-
In Use (xlO )
975
1,058
1,008
846
900
836
503
322
172
67
618
7,305
Annual Mileage**
4,067
2,845
2,072
1,569
1,180
111
630
387
243
162
162
Estimated Total
Annual SVMT
(xlOS)
39.7
30.1
20.9
13.3
10.6
6.5
3.2
1.2
0.4
0.1
1.0
127.0
*SOURCE: Motorcycle Industry Council, Inc. 1979.
** From Table 2-4 of Techniques For Estimating MOBILE2 Variables, 1980.
5-9
-------
TABLE 5-9
CALCULATION OF AVERAGE MILES PER DAY BY VEHICLE TYPE
Vehicle
Type
LDGV
LDDV
LDGT1
LDGT2
LDDT
HDGV
HDDV
MC
VMT per
year (xlO )
1,168,890
123,590
69,822
139,840
62,390
52,625
12,700
VMT per,
day (x!0b)
3,202.44
338.60
191.29
383.12
170.93
144.18
60.48
Estimated
Nationwide
Registrations
102,939,000
12,873,528*
5,667,442
12,873,528*
4,654,514
1,043,764
7,305,000
Average
Miles Per
Day
31.1
31.1
26.3
33.8
29.8
36.7
138.1
8.3
* LDGT1 and LDDT registrations combined.
5-10
-------
6. VEHICLE MILES TRAVELED
Estimates of nationwide vehicle miles traveled are taken from the MVMA
Motor Vehicle Facts and Figures 1979 annual report. These estimates
represent motor vehicle travel in the United States in 1977. The VMT
estimates applicable to apportioning rural and urban travel to the
MOBILE2 categories are presented in Table 6-1. Because the MVMA vehicle
categories do not match those used in MOBILE2, the VMT estimates from
MVMA were weighted by the estimated nationwide registrations to apportion
them to the MOBILE2 categories. Estimated nationwide registrations are
shown in Table 6-2.
In order to apportion the MVMA VMT estimates to the MOBILE2 vehicle
categories, the following assumptions were made:
• Passenger cars in the MVMA terminology are all light-duty
vehicles.
• Motorcycles in the MVMA report match the MOBILE2 category.
• All commercial buses are diesel-powered and all school buses
are gasoline powered.
• All HDDV's that are not commercial buses are combination
trucks.
• Single unit truck VMT is apportioned between LDGT1, LDGT2,
LDDT, and HDGV in proportion to their estimated registration.
Heavy-duty diesel vehicle VMT is estimated as follows:
HDDV VMT = Commercial Bus VMT + Combinations VMT x
Registrations - Commercial Bus Registrations'! (6-1)
Combinations Registration J
- o QQ-, x *Q /« [1,043,764 - 97,900]
- 2,937 + 63,465 ^ i>264>100' J
= 50,425 annual miles
6-1
-------
TABLE 6-1
MOTOR VEHICLE TRAVEL IN THE UNITED STATES, 1977
Single
Passenger Commercial School Unit
Cars Motorcycles Buses Buses Trucks Combinations
Motor Vehicle Travel 1,118,649 22,566 2,957 2,950 266,000 63,465
(Miles x 10 )
Total Rural and
Urban
Percentage of 75.76% 1.53 0.20 0.20 18.01 4.30
Total Annual Travel
^ Number of Vehicles 113,696.1 5,014.6 97.9 393.8 28,298.4 1,264.1
Registered (x 10 )
Source: MVMA, 1979
-------
TABLE 6-2
ESTIMATED NATIONWIDE REGISTRATIONS BY VEHICLE TYPE
Estimated
Vehicle
Type
LDGV
LDDV
LDGT1
LDGT2
LDDT
HDGV
HDDV
MC1
Nationwide
Registrations*
102,711,775
227,225
12,832,570
5,677,442
40,958
4,654,514
1,043,764
7,305,000
Total 127,642,248
*Based on 1978 calendar year registrations.
6-3
-------
The HDGV portion of the combinations VMT is estimated using equation
(6-2):
HDGV VMT = Combinations VMT - HDDV VMT
= 63,465 - 50,425
= 13,040
The school bus VMT is also assumed to be HDGV VMT.
The single-unit truck VMT is also divided between the truck categories
using estimated nationwide registrations. After subtracting the HDGV
registrations already apportioned to combination trucks and school
buses, the truck registrations are:
Vehicle
Types
LDGT1
LDGT2
LDDT
HDGV
Estimated
Registrations
12,832,570
5,677,442
40,958
3,942,478
22,493,448
Percentage of
Total Registrations
.5705
.2524
.0018
.1753
Apportioning the single-unit truck VMT to these categories by registra-
tion gives:
LDGT1
LDGT2
LDDT
HDGV
HDDV
Single Unit
Truck VMT
151,753
67,138
479
46,630
Combinations' Buses' Total
VMT VMT VMT
151,753
67,138
479
13,040 2,950 62,620
50,425 2,957 53,382
335,372
Estimated nationwide VMT for all vehicle types is shown in Table 6-3.
6-4
-------
TABLE 6-3
VEHICLE MILES TRAVELED BY VEHICLE TYPE
NATIONWIDE, AVERAGE ESTIMATES
(Rural and Urban)
Vehicle
Types
LDGV
LDDV
LDGT1
LDGT2
LDDT
HDGV
HDDV
MC
TOTAL
Estimated
Nationwide
VMT (xlO )
1,116,180
2,469
151,753
67,138
479
-62,620
53,382
22,566
1,476,587
VMT
Fractions
.7559
.0017
.1028
.0455
.0003
.0424
.0362
.0153
6-5
-------
TABLE 6-4
VMT FRACTIONS CALCULATED FROM VEHICLE MILES PER DAY
AND NATIONAL REGISTRATION ESTIMATES
ON
I
Vehicle-
Type
LDGV
LDDV
LDGT1
LDGT2
LDDT
HDGV
HDDV
MC
(A)
Vehicle Miles
Per Day
(From Table 5-1)
31.1
31.1
26.3
33.8
29.8
36.7
138.1
8.3
(B)
Estimated
National „
Registrations (xlO )
(From Sec. 3)
102,711.8
227.2
12,832.6
5,677.4
41.0
4,654.5
1,043.8
7,305.0
(A x B)
National
VMT Per, Day
(xlOJ)
3,194,337
7,066
337,497
191,896
1,222
170,820
144,149
60,632
VMT
Fractions
.7777
.0017
.0822
.0467
.0003
.0416
.0351
.0148
4,107,619
-------
An alternative method for estimating fractional vehicle miles traveled
by vehicle type is to use the estimated nationwide registrations from
Section 3 of this report and the average miles/day estimates from Section
5 to estimate VMT by vehicle type. The VMT estimates by vehicle type
and the resulting VMT fractions calculated using this method are shown
in Table 6-4.
The estimated national registrations in Table 6-4 are as determined
using sales data and scrappage rates for each vehicle type. If the
MOBILE2 methodology for estimating LDGV, LDDV, LDGT1, and LDDT registra-
tions is used, the VMT fractions may be somewhat different. For example,
Tables 3-7 and 3-10 can be compared to note the difference in the two
methods for estimating LDDT registrations. In 1978, though, there were
so few LDDV's and LDDT's in the vehicle fleet that the differences in
using the different registration estimates for calculating VMT fractions
would be negligible.
6-7
-------
7. FRACTION OF VEHICLES WITH AIR CONDITIONING
National estimates of the fraction of vehicles with air conditioning by
model year can be taken directly from Section 9 of Techniques for
Estimating MOBILE2 Variables. They are presented in Tables 7-1 and 7-2.
7-1
-------
TABLE 7-1
PERCENTAGE. OF LIGHT-DUTY VEHICLES WITH FACTORY INSTALLED
AIR CONDITIONING BY MODEL YEAR
NATIONAL AVERAGES
Model
Year
1978
1977
1976
1975
1974
1973
1972
1971
1970
1969
1968
1967
1966
1965
1964
1963
1962
1961
1960
1959
* Source:
** Source:
+ Data on
was not
U.S. Cars*
% with
AC
80.8%
81.7
74.0
72.6
67.9
72.6
67.5
63.4
60.1
55.3
44.3
38.0
29.3
23.3
17.9
14.1
11.3
8.1
6.9
6.2
U.S. Cars**
% of
LDV Sales
83%
81
85
82
84
85
85
85
85
89
89
91
93
94
94
95
95
94
93
90
Imports* Imports**
% with % of
AC LDV Sales
30.7% 17%
27.1 19
21.3 15
19.3 18
16
15
15
15
15
11
11
9
7
6
6
5
5
6
7
10
Total*
Fleet
% with
AC
72%
71
66
63
57
62
57
54
51
49
39
35
27
22
17
13
11
8
6
6
Ward's Automotive Yearbook
McNutt, Dulla,
the percentage of
reported in Ward'
and Lax, 1979
imports with
s Automotive
AC for pre-1975 model years
Yearbook. The total fleet
AC percentage for pre-1975 LDV's was calculated assuming no imports
with AC.
7-2
-------
TABLE 7-2
LIGHT-DUTY TRUCKS WITH FACTORY INSTALLED AIR CONDITIONING
BY MODEL YEAR
NATIONAL AVERAGES
Model
Year
1978
1977
1976
1975
1974
1973
1972
1971
1970
* Source:
U.S. Light
Trucks* U.S. LDT's** Imports*
% with % of % with
AC Sales AC
41.2% 93.4% 12.5%
53.2 96.4 10.5
33.3 94.1 2.1
30.6 88.5
29.3 91.6
97.3
92.5
94.6
95.2
Ward's Automotive Yearbook
Imports**
% of
Sales
6.6%
3.6
5.9
11.5
8.4
2.7
7.5
5.4
4.8
Total
Fleet
% with
AC
39%
52
32
27
27
** Source: McNutt, Dulla, and Lax, 1979
7-3
-------
8. AMBIENT CONDITIONS
Table 8-1 gives monthly mean temperatures (dry bulb) for the continental
United States based on ten years of observations. The corresponding
monthly mean relative humidities have been further averaged over all
hours of the day for purposes of this presentation. The humidity factor
H (given in grains of water vapor per pound of dry air) was computed
using the methodology in Section 4.2 of Techniques for Estimating MOBILE2
Variables. These are reported to the nearest whole number. The mean dry
bulb temperature and relative humidity were used to infer corresponding
wet bulb temperatures using standard psychrometric tables. No correction
for ambient pressure variation was made. However, given the lack of
sensitivity and resolution in a nationwide scale analysis of temperature,
such a correction would be superfluous.
The values in Table 8-1 can be used to estimate the frequency of air
conditioning usage in light-duty vehicles and light-duty trucks. Aver-
age monthly dry and wet bulb temperatures can be used in the discomfort
index (DI) equation presented in Section 13 of the Techniques report to
estimate the percentage of air conditioners in use nationwide for each
month. It is strongly recommended that values specific to local means
for the time period of analysis be used in the DI equation whenever
possible.
8-1
-------
TABLE 8-1
AMBIENT CONDITIONS LIKELY TO AFFECT VEHICLE AIR CONDITIONING USAGE
WET BULB TEMPERATURES CORRESPONDING TO MONTHLY
MEAN DRY BULB TEMPERATURES AND MEAN RELATIVE HUMIDITIES
FOR THE UNITED STATES
H(grains
of water
January
February
March
oo
to April
May
June
July
August
September
October
November
December
* Source:
Mean Dry
Bulb (°F)*
45
49
55
65
72
81
85
85
78
68
56
48
Climatography of
Mean Reative vapor/pound
Humidity (%)* of dry air)**
67
64
65
69
72
67
62
62
71
68
67
68
the United
31
36
41
63
91
112
121
121
99
71
44
33
States Series 82
Mean Wet
Bulb (°F)t
40
43
49
59
66
73
75
75
71
61
50
43
Disconfort
Index
49
52
57
65
70
77
79
79
75
67
62
51
AC
Usage
0
0
0
0
0
70%
90%
90%
50%
0
0
0
** To the nearest whole number
t Source: Handbook of Chemistry and Physics
-------
9. VMT PERCENTAGE IN HOT/COLD STARTS
The nationwide average estimates of the VMT percentage in the hot and
cold start modes presented here are based on the simplified method
presented in The Determination of Vehicular Cold and Hot Operating
Fractions for Estimating Highway Emission (Ellis, Camp, and Treadway,
1978). The Simplified Method is based on empirical relationships
between cold and hot operating fractions and the average trip length of
all auto driver trips with origins and destinations within an urban area.
Table 9-1 can be used to estimate cold and hot start VMT percentages by
hour of the day for average trip lengths between 10 and 25 minutes. If
estimates are needed for more than one hour, the cold and hot start VMT
percentages for those hours can be averaged. If possible, it is probably
appropriate to weight the cold and hot start percentages by the percentage
of VMT during that hour to determine a weighted average.
Table 9-1 was derived using urban transportation planning data from six
study areas in Alabama and from the Eastern Massachusetts Regional
Planning Project (EMRPP) which includes Boston. The six study areas in
Alabama range in population from 71,000 to 587,000 persons. All data in
Table 9-1 apply to urban transportation planning study areas as a whole,
and not exclusively to central business districts or any other areas of
a city.
/
According to the NPTS, the average automobile trip length is 8.9 miles.
Therefore, the columns for an average trip length of 20 minutes can be
used for nationwide estimates of cold and hot starts if an average speed
of 26.7 miles per hour is reasonable. The average speed of a light-duty
vehicle or light-duty truck trip is based on the percentage of urban vs.
9-1
-------
TABLE 9-1
PERCENTAGE OF VKT IN COLD AND HOT START MODES
NATIONAL AVERAGES
ATL - 10 Mln.
ATL • 15 Mln.
ATL - 20 Mln.
ATL - 25 Mln.
Hour
Begin.
AH 1
2
3
4
5
6
7
a
9
10
11
12
PM 1
2
3
4
5
6
7
a
9
10
11
Non-
Catalytic
Cold
47.5
49.6
57.3
59.5
63.7
61.2
56.3
45.5
34.2
27.7
17.6
18.8
18.6
22.2
29.2
29.0
28.3
19.5
17.3
14.0
15.8
30.4
43.0
Catalytic
Cold Hot
58.0 10.0
57.6 10:0
61.1 8.5
61.7 7.0
65.6 7.0
62.0 3.0
59.7 10.0
51.8 22.0
47.4 29.0
41.0 36.1
37.0 36.8
35.3 37.7
39.4 38.8
39.3 31.4
42.3 26.7
41.3 29.4
41.7 28.7
40.1 31.8
42.8 31.0
45.0 28.4
47.6 27.6
53.0 17.0
57.7 14.1
Non-
Catalytic
Cold
28.7
29.8
27.3
33.3
31.5
32.1
29.6
22.7
17.0
14.3
10.0
10.8
11.2
13.6
17.9
17.2
16.9
12.1
10.7
9.5
10.5
19.5
24.6
Catalytic
Cold Hot
36.4 7.0
35.4 7.0
29.5 8.0
34.8 7.0
31.7 7.0
32.3 8.0
31.9 10.0
27.3 17.4
24.1 19.5
24.2 23.7
22.6 23.8
21.5 24.5
24.6 22.7
24.5 22.0
25.2 19.4
24.7 19.6
24.7 19.0
24.9 21.0
26.2 21.0
27.5 19.7
30.7 15.2
32.7 11.1
33.5 9.7
Non-
Catalytic
Cold
15.6
17.4
18.7
19.6
20.0
20.0
18.0
14.2
9.3
7.1
5.7
6.0
5.8
6.2
10.4
11.3
11.9
8.0
5.0
3.5
3.7
7.5
11.3
Catalytic
Cold Hot
24.2 3.7
21.9 6.0
21.0 7.2
21.0 7.0
20.0 7.0
20.2 8.0
18.3 10.0
15.2 13.5
13.1 14.3
13.3 16.0
13.2 16.1
13.3 15.2
12.8 14.0
12.3 16.0
14.3 14.4
16.5 21.0
16.3 11.4
14.2 14.6
14.0 14.6
13.7 14.6
17.6 10.0
19.4 8.3
19.3 7.9
Non-
Catalytic
Cold
8.2
16.0
16.2
17.0
18.0
17.0
16.2
13.6
8.3
5.6
4.6
5.0
4.8
4.7
6.8
10.0
10.2
5.0
3.0
2.0
2.7
4.6
7.5
Catalytic
Cold Hot
17.5 3.7
18.8 6.0
19.5 6.7
18.0 7.0
18.0 7.0
17.0 8.0
16.2 10. 0
14.4 10.0
11.2 12.0
10.0 13.0
10.0 12.3
10.0 12.5
10.0 13.0
10.4 12.0
12.0 12.0
U.O 9.7
13.8 8.4
12.0 11.3
11.0 12.0
10.5 12.4
13.2 10.0
15.0 7.0
16.0 8.0
HION
44.7
56.2 13.0
27.3
35.0 10.2
15.0
20.0 7.6
11.8
17.5 5.0
ATL • Average trip length of all Internal auto driver trips.
Source: Ellis, Camps and Treadway, 1978.
9-2
-------
rural driving. Thus, the information in Section 11 of this report can
be used to determine an average trip speed. This average speed can then
be used to derive an average trip length in minutes in order that Table 9-1
can be used.
9-3
-------
10. AVERAGE TRIPS PER DAY WITH EXTRA LOAD AND TOWING TRAILERS
10.1 EXTRA LOAD
The calculations in Table 10-1 show .43 daily trips or 11.2 percent of
all trips by light-duty vehicles involve carrying a heavy load (four or
more occupants). While vacation trips account for a small fraction of
total LDV VMT, they account for a relatively large share of the average
daily trips with extra load.
Since no specific techniques for estimating the percentage of light duty
truck trips with an extra load were presented in Techniques for Estimating
MOBILE2 Variables, no nationwide estimate was made for this vehicle
category.
10.2 TRAILER TOWING
The nationwide average percentage of light-duty vehicles towing trailers
can be estimated using the methodology presented in Section 10.3.2, of
the Techniques report. According to that section, 2.4 percent of all
light-duty vehicles have trailers available. Table 10-1 of that section
shows that vacation trips are 0.132 percent of total trips in all places.
Therefore, multiplying the percentage of light-duty vehicles with trailers
available by the percentage of all trips that are vacation trips yields
a nationwide estimate of 0.0032 percent of LDV trips towing trailers.
Similarly for light-duty trucks, the nationwide estimate for the percentage
of trips with trailers is 0.0054 percent.
10-1
-------
TABLE 10-1
NATIONAL AVERAGE DAILY LDV TRIPS WITH 4 OR MORE OCCUPANTS
PER HOUSEHOLD FOR ALL PLACES
Earning a Living
Family Business
Educational, Civic
& Religious
Vacation
Total
% of Trips
With 4 or More
Occupants
3.3
10.1
22.6
21.3
Daily Trips
per Household
per Purpose
1.4
1.2
0.4
0.8
3.8
Number of Daily
Trips with 4 or
More Occupants
.046
.121
.090
.170
.427
10-2
-------
11. NATIONAL AVERAGE SPEEDS
National average speeds are estimated using speed data from the "CUTS
Manual" (DeLeuw, Gather and Co., 1979), FHWA's Highway Statistics (U.S.
DOT, 1978), and travel fractions by road type and vehicle type from MVMA
(1979). Since vehicles operate at significantly different speeds,
depending on road type, it is necessary to weight speeds by the fraction
of time a particular vehicle type spends on each type of roadway. For
example, light-duty vehicles accumulate a larger share of total VMT on
urban streets and roadways than do heavy-duty diesel trucks; similarly,
heavy trucks accumulate a far greater fraction of total miles on rural
interstates than do LDV's.
The estimated average speeds are shown in Tables 11-1 through 11-4. Not
surprisingly, heavy trucks average much higher speeds than LDV's and
light trucks. The average 37.9 mph for LDV's is substantially higher
than the 19.6 mph used in MOBILE1. The explanation of this discrepancy
is that MOBILE1 speed data are based on urban driving (Federal Test
Procedure). The MOBILE2 estimate accounts for nationwide VMT accumula-
tion which presumably has a much larger share of cruise speed driving on
both interstate and state highways.
Highway speeds were not broken down by vehicle type by FHWA. Since the
State of Michigan provides highway speeds by roadway type for two cate-
gories of vehicles (passenger and commercial) it is possible to use
Michigan data to weight the national average speeds and disaggregate
passenger and commercial vehicle speeds. Table 11-5 shows these calcu-
lations. It was assumed that all light-duty vehicles and light trucks
are passenger vehicles; heavy trucks and buses were assumed to be commercial
vehicles. The ratio of national to Michigan speed for all vehicles for
11-1
-------
TABLE 11-1
NATIONAL AVERAGE SPEEDS
FOR LIGHT-DUTY VEHICLES
Fraction of all*
Roadway Type Speed LDV Travel
Interstate rural 59.8 .073
Other main rural 55.8 .274
Local rural 25.0** .069
Interstate urban 56.8 ' .106
Other urban 22.0 .478
CBD 15.0
Fringe 22.0
Residential 26.0
Outlying Business District 18.0
Weighted average speed 37.9
* MVMA, 1979.
** Assumed, based on state law maximum speeds in incorporated areas.
Assumes 75 percent volume-to-capacity ratio.
11-2
-------
TABLE 11-2
NATIONAL.AVERAGE .SPEEDS
FOR ALL LIGHT-DUTY TRUCKS
(LDGT1, LDGT2, LDDT)
Fraction of all*
Roadway Type Speed LPT Travel
Interstate rural 59.8 .075
Other main rural 55.8 .356
Local rural 25.0** .037
Interstate urban 56.8 .058
Other urban 22.0+ .474
CBD 15.0
Fringe 22.0
Residential 26.0
Outlying business district 18.0
Weighted average speed . 39.0
* MVMA, 1979.
** Assumed, based on state law maximum speeds in incorporated areas.
Assumes 75 percent volume-to-capacity ratio.
11-3
-------
TABLE 11-3
NATIONAL AVERAGE SPEEDS FOR
HEAVY-DUTY GASOLINE VEHICLES
Fraction of all**
Roadway Type
Interstate rural
Other main rural
Local rural
Interstate urban
Other urban
CBD
Fringe
Residential
Outlying business district
Weighted average speed
Speed*
60.5
53.9
25. 0+
54.1
22.0++
15.0
22.0
26.0
18.0
41.3
HDGV Travel
.130
.379
.042
.066
.383
* Commercial vehicle speeds used since school bus VMT is only 5 percent
of total HDGV VMT.
** MVMA, 1979.
Assumed,-based on state law maximum speeds in incorporated areas.
Assumes 75 percent volume-to-capacity ratio.
11-4
-------
TABLE 11-4
NATIONAL AVERAGE SPEEDS FOR
HEAVY-DUTY DIESEL VEHICLES
Roadway Type
Interstate Rural
Other Main Rural
Local Rural
Interstate Urban
Other Urban
CBD
Fringe
Residential
Outlying Bus. Dist.
Weighted Average Speeds
by Vehicle Type 52.6 mph
Weighted Average Speed
for all HDDV 51.6 mph
Truck Travel*
Truck Speeds Fraction
Bus Travel*
Bus Speeds Fraction
60.5 .342
53.9 .452
25.0** .016
54.1 .093
-L.
22.0 .097
15.0
22.0
26.0
18.0
60.5
53.9
25.0**
30.0
4.
11.0
5.0
11.0
11.0
15.0
.100
.270
.031
.106
.493
30.0 mph
* MVMA, 1979.
** Assumed, based on state law maximum speeds in incorporated areas.
Assumes 75 percent volume-to-capacity ratio.
Weighted by relative shares of total diesel VMT:
Truck fraction = .956 (calculated from Section 6)
Bus fraction = .0442 (calculated from Section 6)
VMT weighted average speed = (52.6 x .956) + (30.0 x .0442)
11-5
-------
TABLE 11-5
CALCULATIONS OF NATIONAL SPEEDS FOR
THE DIFFERENT VEHICLE TYPES
A. Calculations of Average Speed Values for Light Duty Vehicles
1. Interstate Rural
National Average Speed on Interstate Rural 58.8 tnph
Michigan Average Speed on Interstate Rural 57.8 mph
Ratio (Correction Factor) = 58.8/57.8
= 1.017
Michigan Average Passenger Car
Speed on Interstate Rural = 58.8
National Average Passenger Car
Speed on Interstate Rural = 59.8
2. Other Main Rural
Other Main Rural is defined as the average of Multi-lane
Divided and 2-lane Rural
Average of Multi-lane Divided and 2-lane Rural for
National Value = 56.5 + 54.9
2
- 55.7
National Other Main Rural =55.7
Michigan Other Main Rural = 57.6 + 54.7
2
= 56.15
Correction Factor = 55.7/56.15
- .992
Michigan Average Passenger Car
Speed on Other Main Rural = 57.9 + 54.5
2
= 56.2
11-6
-------
TABLE 11-5 (Cont'd)
National Average Passenger Car
Speed on Other Main Rural = 56.2 x .992
= 55.75
3. Interstate Urban
National Average Speed on Interstate Urban = 56.7
Michigan Average Speed on Interstate Urban = 56.4
Correction Factor 56.7/56.4
- 1.0053
Michigan Average Passenger Car Speed on
Interstate Urban = 56.5
National Interstate Urban = 56.5 x 1,0053
= 56.8
B. Calculations of Average Speed Values for Light Trucks
These are the same as the speed values for light duty vehicles
C. Weighted Average Speed for LDV
Formula Weighted Average Speed = (Speed)(fraction LDV Travel)
n
D. Calculations of Speeds of Heavy Duty Vehicles
These are the same for heavy duty trucks and buses
11-7
-------
TABLE 11-5 (Cont'd)
Class
Interstate
Rural
Other Main Rural
(Multi-Lane Divided
2 Lane Rural)
Interstate
Urban
Michigan
Average
Commercial
Vehicle Speed
59.5
55.7 + 52.9
2
= 54.3
53.8
National
Correction Commercial
Factor Average Speed
1.017
.992
1.0053
60.5
53.9
54.1
The Weighted Average Speeds for both heavy duty trucks and
commercial buses was worked out as follows:
(speed)(fraction LDV travel)
n
11-8
-------
each roadway type was computed and used as a correction factor. Then,
for example, the Michigan average passenger car speed, for a particular
roadway type, was multiplied by the appropriate correction factor to
estimate national average passenger car speed. The same procedure was
used for commercial vehicles.
The fractions of travel by vehicle type were obtained directly from MVMA
in most cases. Since the heavy-duty gas truck category did not match
MVMA's categories, the HDGV travel fractions were weighted according to
the procedure shown in Table 11-6. This weighting of MVMA categories is
consistent with that used in Section 6 of this document.
11-9
-------
TABLE 11-6
CALCULATION OF FRACTION OF HDGV VMT BY ROADWAY TYPE
HDGV VMT - 62,620 100.0%
single unit 46,630 74.5%
combination , 13,040 20.8%
school buses 2,950 4.7%
VMT FOR MVMA VEHICLE TYPE BY ROAD TYPE
Single Unit Combination School Bus
Interstate Rural
Other Main Rural
Local Rural
Interstate Urban
Other Urban
0. .075
L! .356
.037
XL .058
.473
HDGV WEIGHTED FRACTION
Single Unit
.1 .056
il .265
.028
.n .044
.352
.745
.342
.452
.016
.093
.097
OF VMT BY ROAD
Combination
.071
.094
.004
.019
.020
.208
.056
.419
.217
.070
.238
TYPE
School Bus
.003
.020
.010
.003
.011
.047
Total
Interstate Rural .056 .071 .003 .130
Other Main Rural .265 .094 .020 .379
Local Rural .028 .004 .010 .042
Interstate Urban .044 .019 .003 .066
Other Urban .352 .020 .011 .383
1.000
11-10
-------
REFERENCES
DeLeuw, Gather and Co. 1979. Characteristics of Urban Transportation
Systems; A Handbook for Transportation Planners. (Prepared for the
Urban Mass Transportation Administration, U.S. DOT.)
Ellis, G.W., Camps, W.T., and Treadway, A. September 1978. The Deter-
mination of Vehicular Cold and Hot Operating Fractions for Estimating
Highway Emissions. State of Alabama Highway Department. Montgomery,
AL. (Prepared for U.S. DOT - FHWA.)
Jambekar, A, and Johnson, J. 1977. The Development of an Emission
and Fuel Economy Computer Model for Heavy-Duty Trucks and Buses.
Michigan Technological University. Houghton, MI.
McNutt, B., Dulla, R., and Lax, D. February 1979. "Factors
Influencing Automotive Fuel Demand," SAE Technical Paper Series.
Paper No. 790226. Congress and Exposition. Detroit, MI.
Motor Vehicle Manufacturers Association. 1979. Motor Vehicle Facts
and Figures. Detroit, MI.
Murrell, J.D., Foster, J.A. and Bristor, D.M. June 1980.
"Passenger Car and Light Truck Fuel Economy Trends through 1980".
SAE Technical Paper Series. Paper No. 800853. Dearborn, MI.
U.S. Department of Transportation. 1978. Highway Statistics. Federal
Highway Administration. Washington, D.C.
U.S. Environmental Protection Agency. October 1979. Summary and
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