DOE/EIA-0464(91)

Distribution Category UC-950

Household Vehicles Energy Consumption 1991

December 1993

Energy Information Administration

Office of Energy Markets and End Use

U.S. Department of Energy

Washington, DC 20585

This report was prepared by the Energy Information Administration, the independent statistical and analytical

agency within the Department of Energy. The information contained herein should not be construed as

advocating or reflecting any policy position of the Department of Energy or any other organization.
Contacts

This publication was prepared by the Energy Information Administration (EIA) under the general direction of W.

Calvin Kilgore, Director of the Office of Energy Markets and End Use (202-586-1617). The project was directed

by Lynda T. Carlson, Director of the Energy End Use and Integrated Statistics Division (EEUISD) (202-586-1112)

and Dwight K. French, Chief of the Transportation and Industrial Branch (202-586-1126). Specific technical

information may be obtained from the Residential Transportation Energy Consumption Survey (RTECS) Manager,

F. Ronald Lambrecht (202-586-4962). The FAX number for all EEUISD personnel is 202-586-0018.

Detailed technical questions on the topics indicated may be referred to the following members of the EEUISD:

RTECS Manager F. Ronald Lambrecht 202-586-4962

Vehicle Miles Traveled John Pearson 202-586-6160

Trends in Household Vehicle Stock F. Ronald Lambrecht 202-586-4962

Fuel Efficiency and Fuel Consumption Alan Swenson 202-586-1129

Appendix A F. Ronald Lambrecht 202-586-4962

Appendices B and C Ivy Harrison 202-586-5931

Detailed Statistical Tables

and Report Production Vicki Moorhead 202-586-1133

Public Use Data, Computer Systems

Design, Detailed Statistical Tables Nanno Smith 202-586-5841

Related Statistical Publications

and Report Production Hattie Ramseur 202-586-1124

Senior-Level Advisor John Pearson 202-586-6160

Support was received from the Office of Minority Economic Impact of the U.S. Department of Energy for special

components of the survey.

ii Energy Information Administration/Household Vehicles Energy Consumption 1991
As part of EIA’s mission to provide meaningful data, the consumption surveys have ongoing user needs efforts

to ascertain the requirements of its users. If you have any suggestions to make the data in this report more

useful to your needs, please contact F. Ronald Lambrecht, RTECS Manager, at 202-586-4962 or at the address

below.

If you have any data or report-related requirements or suggestions for any of the other EIA consumption

surveys, please contact the appropriate survey manager directly, or use the address below.

Commercial Buildings Energy Consumption Survey (CBECS): Martha Johnson, Survey Manager, at

202-586-1135.

Manufacturing Energy Consumption Survey (MECS): John Preston, Survey Manager, at 202-586-1128.

Residential Energy Consumption Survey (RECS): Wendel Thompson, Survey Manager, at 202-586-

1119.

You are encouraged to provide your comments to the survey managers. Your feedback is important to us.

EI-63, Mail Stop 2G-090

1000 Independence Avenue, SW FAX: 202-586-0018

Washington, DC 20585

Energy Information Administration/Household Vehicles Energy Consumption 1991 iii
Contents

Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

1. Introduction ................................................................... 1

Background .................................................................... 1

Other Data Sources .............................................................. 2

Organization of the Report ......................................................... 2

2. Trends in Household Vehicle Stock .................................................. 5

Number of Household Vehicles ..................................................... 5

Vehicle Stock Composition ........................................................ 9

Change in Vehicle Stock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Average Number of Vehicles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3. Vehicle Miles Traveled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Total and Average Vehicle Miles Traveled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Insights from the Nationwide Personal Transportation Survey (NPTS) . . . . . . . . . . . . . . . . . . . . . . . . . . 23

4. Vehicle Fuel Efficiency and Consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Vehicle Fuel Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Vehicle Fuel Consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Potential Fuel Savings from Replacing Old Vehicles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Fuel Consumption in Households Participating in Income Supplement Programs . . . . . . . . . . . . . . . . . . . . 40

Detailed Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Table Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Row and Column Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Quick-Reference Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Appendices

A. How the Survey Was Conducted . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

B. Estimation Methodologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

C. Quality of the Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

D. Survey Forms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

E. U.S. Climate Zone and Census Regions and Divisions Maps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201

F. Related EIA Publications on Energy Consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205

Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

Tables

1. Comparison of Household and Total Vehicle Stock ...................................... 7

2. Households by Number of Vehicles and 1990 Family Income, July 1991 ........................8

3. Number of Vehicles by Model Year and Census Region, 1991 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

4. Changes in Vehicle Stock by Selected Household Characteristics, 1991 . . . . . . . . . . . . . . . . . . . . . . . 12

5. Annual Percent Change in Vehicles and Vehicle Miles Traveled, 1983, 1985, 1988, 1991 . . . . . . . . . . . . 15

Energy Information Administration/Household Vehicles Energy Consumption 1991 v
6. U.S. per Household Vehicle Miles Traveled, Vehicle Fuel Consumption and

Expenditures for Income Supplement Programs, 1991 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

7. Summary of Household and Vehicle Characteristics by Categories of Income Assistance, 1991 . . . . . . . . 42

8. Number of Vehicles, Vehicle Miles, Motor Fuel Consumption and Expenditures, 1991 . . . . . . . . . . . . . 45

9. U.S. per Household Vehicle Miles Traveled, Vehicle Fuel Consumption and Expenditures, 1991 . . . . . . 49

10. U.S. per Vehicle Miles Traveled , Vehicle Fuel Consumption and Expenditures , 1991 . . . . . . . . . . . . . 51

11. U.S. Vehicles by Model Year, 1991 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

12. U.S. Vehicle Fuel Efficiency by Model Year, 1991 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

13. U.S. Average Vehicle Fuel Consumption by Vehicle Model Year, 1991 . . . . . . . . . . . . . . . . . . . . . . . . 61

14. U.S. Vehicle Miles Traveled by Family Income, 1991 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

15. U.S. Vehicle Fuel Consumption by Family Income, 1991 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

16. U.S. Average Vehicle Miles Traveled by Family Income, 1991 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

17. U.S. Average Vehicle Fuel Consumption by Family, 1991 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

18. U.S. Vehicles by Household Composition 1991 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

19. U.S. Average Vehicle Miles Traveled by Household Composition, 1991 . . . . . . . . . . . . . . . . . . . . . . . . 78

20. U.S. Average Vehicle Miles Traveled by Vehicle Fuel Efficiency Category, 1991 . . . . . . . . . . . . . . . . . 80

21. U.S. Vehicle Fuel Consumption by Vehicle Type, 1991 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

22. U.S. Average Vehicle Miles Traveled by Vehicle Type, 1991 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

23. Number of Vehicles by Vehicle Type, 1991 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

24. Number of U.S. Households by Vehicle Fuel Expenditures, 1991 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

25. U.S. Average Household Energy and Vehicle Expenditures, 1991 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

26. U.S. Average Household Energy and Vehicle Consumption, 1991 . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

27. U.S. Households by Changes in Vehicle Stock, 1991 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

B1. Distribution of Average Monthly Vehicle Miles Traveled Fractions . . . . . . . . . . . . . . . . . . . . . . . . . . 130

B2. Distribution of Residential Transportation Energy Consumption Survey

Vehicles by Type of Fuel Used, 1991 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

C1. Average Bureau of Labor Statistics Gasoline Prices and 1985 Residential Transportation

Energy Consumption Survey Prices by Census Region and Fuel Type . . . . . . . . . . . . . . . . . . . . . . . . 151

C2. Average Bureau of Labor Statistics Vehicle Fuel Expenditures and 1985 Residential Transportation

Energy Consumption Survey Vehicle Fuel Expenditures by Census Region and Fuel Type . . . . . . . . . . 153

Illustrations

1. RTECS and Other Estimates of Households and Total Vehicles ..............................5

2. Total Household Vehicle Ownership, and Ownership by Income ..............................8

3. Household Vehicle Composition, 1991 ................................................9

4. Vehicle Stock Composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

5. Trends in Vehicles and Population Ratios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

6. Household and Vehicle Miles Traveled by Survey Year . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

7. Average Household Vehicle Miles Traveled and the Number of Drivers . . . . . . . . . . . . . . . . . . . . . . . . 18

8. Average Household Vehicle Miles Traveled and Income . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

9. Average Vehicle Miles Traveled per Vehicle and Age of Primary Driver . . . . . . . . . . . . . . . . . . . . . . . 20

10. Average Vehicle Miles Traveled and Vehicle Age . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

11. Average Household Vehicle Miles Traveled and Census Regions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

12. Trends in Vehicle-Trip Length, 1983 and 1990 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

13. Average Fuel Efficiency of All Vehicles by Model Year . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

14. Average Fuel Efficiency of All Vehicles by Type of Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

15. Average Fuel Efficiency of All Vehicles by Census Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

vi Energy Information Administration/Household Vehicles Energy Consumption 1991
16. Average Fuel Efficiency of All Vehicles by Household Composition . . . . . . . . . . . . . . . . . . . . . . . . . . 32

17. Average Fuel Efficiency of All Vehicles by 1990 Family Income . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

18. Average Annual Household Fuel Consumption by Census Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

19. Average Annual Vehicle Fuel Consumption by Census Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

20. Average Annual Household Fuel Consumption by Household Composition . . . . . . . . . . . . . . . . . . . . . . 36

21. Total Annual Vehicle Fuel Consumption by Vehicle Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

22. Average Annual Vehicle Fuel Consumption by Vehicle Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

23. Average Annual Vehicle Fuel Consumption by Vehicle Model Year . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

A1. Example of a Decoded Vehicle Identification Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

A2. Location of the Vehicle Identification Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

B1. Estimation Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

B2. Miles per Gallon Adjustment Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

C1. Use of RSE Row and Column Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156

Energy Information Administration/Household Vehicles Energy Consumption 1991 vii
Executive Summary

This report, Household Vehicles Energy Consumption 1991, is based on data from the 1991 Residential

Transportation Energy Consumption Survey (RTECS). Focusing on vehicle miles traveled (VMT) and energy enduse consumption and expenditures by households for personal transportation, the 1991 RTECS is the fifth in a series

conducted since 1978 by the Energy Information Administration (EIA). Over 3,000 households with more than 6,000

vehicles were surveyed, providing information on their vehicle stock and annual miles traveled per vehicle. The

information provided represents the characteristics and energy consumption of the 84.6 million households with

vehicles nationwide. An additional 10 million households did not own or have access to a vehicle during the survey

year.

Use of residential vehicles and fuels in 1991 showed little change from 1988 and was indicative of the current state

of personal transportation in America. Two noticeable changes for 1991 were a small increase in the average number

of miles traveled both per household1 and per vehicle, and a slight decrease in the average consumption of motor

vehicle fuel per household. An increase in the average fuel efficiency (miles per gallon-MPG), was the reason for

the decreased consumption. However, vehicle fuel expenditures per household rose by 16 percent between 1988 and

1991, primarily due to a 21 percent rise in the price of vehicle fuel.

Results from the 1991 RTECS indicate that:

Annual vehicle miles traveled per household and per vehicle were 18.9 and 10.6 thousands respectively.

The average number of vehicles per household did not change between the 1988 and 1991 RTECS: Both

surveys reported approximately 1.8 vehicles per household.

The total number of vehicles in the U.S. stock by vehicle type remained approximately the same for 1991

and 1988. The exception has been minivans and sport-utility vehicles (listed as jeep-like vehicles in

previous publications), which have almost doubled from 7 million to 12.4 million and are classified as trucks

for fuel efficiency standards.

Approximately 9 percent of the vehicle stock consisted of pre-1975 models.

Average fuel consumption was 979 gallons per household and 548 gallons per vehicle, both down slightly

from 1988, though not statistically significant.

In 1991, the average on-road vehicle MPG was 19.3, up 5 percent from 18.32 in 1988. This change resulted

from retiring old vehicles and purchasing newer models which are more fuel efficient. The size of the

increase was limited by the increased sales of vehicles classified as trucks (i.e., minivans and sport-utility),

which have lower fuel efficiency standards3.

1

Per household numbers are only for households with vehicles unless otherwise stated.

2

The methodologies for calculating fuel efficiency, fuel consumption, and fuel expenditures were the same as in the 1988 RTECS. See

Appendix B, "Estimation Methodologies" and Appendix C, "Quality of the Data."

3

According to Department of Transportation statistics, there has been essentially no improvement in the overall efficiency of the new car fleet

for the last 10 years. In actuality, efficiency has been declining since 1988. The availability of inexpensive fuels, desire for larger and faster

vehicles, and flashy advertising are probably the main factors contributing to this phenomena.

Energy Information Administration/Household Vehicles Energy Consumption 1991 ix
In 1991, households spent an average of $1,161 for vehicle fuel compared to $998 per household in 1988.

x Energy Information Administration/Household Vehicles Energy Consumption 1991
Lower-income households appear to be paying a larger percentage of their income on vehicle fuel.

Household vehicles consumed 10.3 quadrillion Btu of vehicle fuel, the same as in 1988. This represents

approximately 31 percent of the 32.8 quadrillion Btu of all petroleum consumption in the United States

and 13 percent of the total U.S. energy consumption of 81.1 quadrillion Btu.

In 1991, combined household energy expenditures were $2,333 for both their housing unit and vehicles, with

vehicle fuel purchases accounting for 50 percent. In 1988 only 47 percent of household energy expenditures

were for vehicle fuel.

The 1991 RTECS provides baseline information on motor vehicle use in the residential sector. To be included in

this survey one of two criteria must be met. Vehicles must be (1) owned or used by household members on a

regular basis for personal transportation or (2) company vehicles, not owned by the household, but kept at home and

regularly available to household members. Data from the RTECS and a companion household survey, the Residential

Energy Consumption Survey, are available to the public in published reports and on public-use personal computer

diskettes for the 1988 and 1991 surveys and on 9-track tapes for all years.4

Table ES1 summarizes selected vehicle energy-related items from the 1991 RTECS. This table allows the reader to

easily discern energy information related to vehicle characteristics. The household averages in this table are based

on households with vehicles.

Table ES1. Summary of Vehicle Characteristics by Census Region, 1991

Vehicle Characteristics U.S. Total Northeast Midwest South West

Number of Households

(millions) ...................... 94.6 19.3 23.4 32.3 19.6

Number of Households with Vehicles

(millions) ...................... 84.6 16.0 21.1 29.5 18.0

Number of Vehicles

(millions) ...................... 151.2 27.0 38.4 52.7 33.2

Vehicle Miles Traveled

(billions) ....................... 1,602 295 403 571 333

Vehicle Fuel Consumption

(billion gallons) ................. . 82.8 14.1 21.3 29.8 17.6

Number of Vehicles per Household . 1.8 1.7 1.8 1.8 1.8

Vehicle Miles Traveled per Household

(thousands) .................... 18.9 18.5 19.1 19.3 18.5

Vehicle Miles Traveled per Vehicle

(thousands) .................... 10.6 10.9 10.5 10.8 10.0

Vehicle Fuel Efficiency

(miles per gallon) ................ 19.3 20.9 19.0 19.2 18.9

Note: Because of rounding, data may not sum to totals.

4

See Appendix F, "Related EIA Publications on Energy Consumption," for a list of EIA publications available concerning the consumption

of energy.

Energy Information Administration/Household Vehicles Energy Consumption 1991 xi
Source: Energy Information Administration, Office of Energy Markets and End Use, 1991 Residential Transportation Energy

Consumption Survey.

xii Energy Information Administration/Household Vehicles Energy Consumption 1991