ENERGY OVERVIEW 

ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS
ENERGY OVERVIEW

ENERGY OVERVIEW 

INTRODUCTION Author’s Note 

Estimates of gallons of fuel 

consumed, type of fuel used, price 

paid for fuel, and fuel economy are 

based on data imputed by EIA, 

using vehicle characteristics and

vehicle-miles traveled data collected

during the interview process for the

2001 National Household Travel 

Survey (NHTS). Rather than 

obtaining that information directly

from fuel purchase diaries, EIA

exploited its experience and 

expertise with modeling techniques 

for transportation studies, filling 

missing and uncollected data with

information reported to other federal 

agencies, as described in Appendices

B and C of this report. 

Had these imputed data items 

been derived from information

supplied by respondents directly, it is 

likely that the systematic and random 

sources of measurement variability

associated with them would have 

been similar to those found with all 

NHTS population estimates, thereby

capturing the behaviors and patterns 

associated with a household and its 

members. Since energy and energyrelated data were imputed, these data

are subject to additional uncertainty. 

This report, Household Vehicles Energy Use:

Latest Data & Trends, provides details on the nation’s

energy use for passenger travel. Drawing on several

databases made available to the Energy Information 

Administration (EIA) from other federal agencies, and 

EIA’s past Residential Energy Consumption Surveys 

(RTECS), EIA reports on the number and types of

vehicles per household, and for each vehicle: annual 

miles traveled, gallons of fuel consumed, type of fuel 

used, price paid for fuel, and fuel economy (see Text 

Box). 

DATA SOURCES 

The latest source for vehicle and household

estimates and associated public-use files is the January 

2004 release of the 2001 National Household Travel 

Survey (NHTS), a national study funded and 

coordinated by the U.S. Department of Transportation

(DOT), which included the Federal Highway 

Administration (FHWA), Bureau of Transportation 

Statistics (BTS), and the National Highway Traffic 

Safety Administration (NHTSA). The NHTS is the 

integration of two national travel surveys: the Federal 

Highway Administration-sponsored Nationwide 

Personal Transportation Survey (NPTS) and the 

Bureau of Transportation Statistics-sponsored 

American Travel Survey (ATS). 

For this report, EIA augmented the fundamental 

household and vehicle data released by the 2001 

NHTS, which is the nation’s inventory of local and

long-distance travel. Between April 2001 and May 

2002, roughly 26 thousand sample households9

 were

 9

 The NHTS collected travel data from the civilian, non-institutionalized population of the United States. People living 

in medical institutions, prisons and in barracks on military bases were excluded from the sample. However, telephone 

numbers in dormitory rooms, and fraternity and sorority houses were included as long as no more than 10 people 

shared the same telephone number. 

ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA &

TRENDS

10
ENERGY OVERVIEW

Author’s Note (continued)

To measure one aspect of that

uncertainty, EIA conducted a 

sensitivity analysis of imputed fuel 

economy (i.e., gasoline mileage) 

values. Schipper and Pinckney 

(2004) determined that consumption 

could have been either raised by 7

percent or lowered by 9 percent, if 

EIA in its cold-deck imputation 

scheme had always chosen

excessively extreme fuel economy

values, selecting the 5th percentile 

(P5) value or the 95th percentile

(P95) value as the representative fuel

economy for each sampled vehicle. 

By using only extreme values -

P5 or P95 - results are biased. While 

these extreme values are not 

acceptable to a researcher, such 

biased estimates, to some extent,

illustrate the upper and lower 

uncertainty bounds associated with 

cold-decked estimates. Given these

bounds, along with survey sampling 

and non-sampling errors, the use and 

usefulness of an enhanced NHTS

should be evaluated against a 

researcher’s project requirements. 

interviewed about their travel based on the use of over

53 thousand light-duty vehicles (referenced hereafter 

as “vehicles”)10, representing 107.4 million 

households in the United States, of which 92 percent 

(98.9 million) actually owned or possessed a vehicle 

during the survey period.. Although trip and travel

data are mandated components of the NHTS, fuel 

prices and energy consumption are not. Using 

confidential data collected during those interviews,

coupled with EIA’s retail fuel prices, external data

sources of test

11 fuel economy, and internal procedures 

for modifying test fuel economy to on-road, in-use 

fuel economy, EIA extended this inventory to include 

the energy consumption and expenditures demanded

for personal transportation, thereby extending a data

series previously based on EIA’s Residential

Transportation Energy Consumption Survey

(RTECS), which was discontinued for budgetary

reasons after 1994. 

Until it was discontinued, the RTECS surveys 

provided residential transportation statistics which

were summarized in the report series Household 

Vehicle Energy Consumption. Decision- and policymakers had found such reports and public-use 

databases useful, for they had coupled vehicle use,

travel, consumption, and expenditure information with 

socio-economic, demographic, and household

information.12 This rich data source tracked the 

continued dominance of the personal passenger

vehicle as the preferred travel mode by the American

public, assessed shifts in the nation’s vehicle stock and

its impact on overall fuel economy and consumption, 

and enhanced the knowledge of public and policy-

 10 To avoid misinterpretation of averages, statistics in this report are based on the domain of households that possessed

a light-duty vehicle during the survey period of the 2001 National Household Travel Survey, effectively removing 8.5

million American households that did not possess a vehicle during the survey period. 

11 Federal law, 49 USC § 32908, requires automobile manufacturers to determine the fuel economy of new vehicles 

offered for sale in the United States. This information is provided on a fuel economy label affixed to each vehicle’s

window to help consumers make informed decisions regarding fuel economy when purchasing a new vehicle. While 

these labels may vary somewhat in appearance, they all must provide the same information. 

12 Since 1983, and until it was discontinued after 1994, EIA’s survey of residential transportation collected vehicle 

odometer readings to calculate annual vehicle-miles traveled; however beginning in 1988, instead of collecting fuel 

purchase diaries for fuel economy and fuel price data, fuel economy values were obtained by linking with EPA’s tested

fuel economy values; and fuel prices were obtained from a variety of pump price data series. 

ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS 11
ENERGY OVERVIEW

makers on how variations of use among different socio-economic groups might relate to potential 

policy initiatives, such as assessing the potential effects of public policy initiatives on lower and

higher income households or elderly populations13 within the nation. 

ORGANIZATION OF REPORT 

This report is organized as follows: 

• Energy Overview presents data highlights and an analysis that disaggregates energy 

use based on relationships among energy-related transportation statistics. 

• Appendix A: Detailed Tables presents tabular data on the vehicle stock and energy

use for personal transportation. 

• Appendix B: Estimation Methodologies discusses how statistics were estimated,

which rely heavily on the methods employed with previous residential transportation 

surveys conducted by EIA. 

• Appendix C: Quality of the Data discusses the quality of the reported and imputed 

vehicle data, including the effects of sampling, non-sampling, and imputations on 

data quality.

• Appendix D: Description of Data describes how researchers can access and 

manipulate public-use files made available by EIA and U.S. DOT. 

• Appendix E: Chronology of World Oil Market Events presents major market

events in sequence with world oil prices. 

• Glossary provides a list of key terms used herein. 

Only light-duty passenger vehicles and recreation vehicles (i.e., motor homes) are included 

in this report. EIA has excluded motorcycles, mopeds, large trucks, and buses in an effort 

to maintain consistency with its past residential transportation series, which was

discontinued after 1994. 

 13 Rosenbloom, S. Older Drivers: Should We Test Them Off the Road? University of California, Transportation Center, 

Access, Fall 2003, Number 23. 

12 ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS
ENERGY OVERVIEW

ENERGY PROFILE 

Based on EIA data, two transportation perspectives can be considered: top-down 

(representing weekly, monthly, and yearly queries of energy transporters and suppliers) and

bottom-up (representing multi-year queries of final consumers). 

Figure 1. Total Energy Consumption by End-Use Sector, 1949-2004

0

20

40

60

80

100

120

1949195119531955195719591961196319651967196919711973197519771979198119831985198719891991199319951997199920012003

Year

Quadrillion Btu

Transport

Industrial

Commercial

Residential

In 2004, petroleum products accounted for 97 percent of the

sector's energy, and motor gasoline accounted for two-thirds of

all petroleum used in the sector.

Source: Energy Information Administration. 

TOP-DOWN VIEW

In 2004, based on EIA’s queries of energy transporters and suppliers, the United States

consumed 99.7 quadrillion British thermal units (Btu) of energy, 105.2 exajoules (EJ), a slight

increase from 103.7 EJ (98.3 quadrillion Btu) in 2003. Of that total amount in 2004, 33.2 

quadrillion Btu (33 percent of the total) was categorized as industrial use, 27.8 quadrillion Btu 

(28 percent) was transportation use for all modes of transport, 21.2 quadrillion Btu (21 percent) 

was residential use and 17.5 quadrillion Btu (18 percent) was commercial use (see Figure 1). For 

transport, 97 percent of the energy supplied was petroleum-based. 

The nation currently cannot provide for all its petroleum demand with domestically produced

crude oil. The decline in domestic oil production, coupled with a rise in oil consumption, resulted

in net imports of crude oil and petroleum products surpassing 11.2 million barrels per day in 

2003, with imports reaching an all-time high of just over 12.2 million barrels per day, of which

over 40 percent had originated at countries belonging to the Organization of Petroleum Exporting

Countries (OPEC). Furthermore, motor gasoline accounted for nearly one-half (8.9 million

barrels per day) of the 20 million barrels per day of petroleum products consumed domestically in 

2003, with 13.2 million barrels per day of that total identified as transport sector use. 

Despite the rich accounting of monthly and yearly energy data, sector-level estimates are too 

broadly defined for demand analyses trying to identify and quantify the impact of factors driving 

the overall change in consumption. Top-down data reveal few insights into those influences,

ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS 13
ENERGY OVERVIEW

14 ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS

generally brought about by changing activity, structure, and energy intensity associated with 

households’ vehicles and how the public use their privately owned vehicles (POV) for personal 

transportation. 

BOTTOM-UP VIEW OF PERSONAL TRANSPORTATION 

Consumer data fill that gap left by top-down data. Bottom-up data are based on intermittent 

surveys of the nation’s final consumers: manufacturing plants, commercial buildings, households, 

and, for this report, household vehicles.14 These consumer-based surveys can provide a wide 

variety of end-use characteristics that enables the insights not possible with sector-level data. 

COSTS RISE FOR U.S. HOUSEHOLDS

For consumers, energy costs are a foremost concern. Transportation costs have increased due 

to many factors related to travel and prices paid for transportation fuel, while being somewhat 

offset by improved fuel economy. In 2001, consumers paid nearly equal amounts for energy used 

for household services (ranging from cooking and water heating to refrigeration and lighting) and 

for personal transport. The average household spent $1,520 on fuel purchases for transport and 

remitted $1,493 for household services, just $27 more per year, as measured in nominal dollars. 

By contrast, an average household paid $1,174 for passenger travel in 1994, while having 

paid $1,620 for household services in 1993 – a year in which heating and cooling seasons were 

well within 30-year norms. It can be argued that, based on those statistics, what America drives 

on its roadways15 has become as important energy-wise as what heating equipment it places in its 

basements and appliances in its electrical sockets. 

PRICES EXPECTED TO MOVE HIGHER

Based on expected future energy prices which partially reflect producers’ acquisition costs, 

the gap between transport cost and household services cost may expand. Between 2001 and 2006, 

expenditures for motor gasoline are expected to increase from $1,370 per household per year to 

$2,327 in 2006, up nearly $960 per household. For comparison, in 2001, gasoline prices averaged 

$1.43 per gallon; in 2006, gasoline prices are expected to average $2.43 per gallon (a 71-percent 

increase in nominal terms and 52-percent increase when adjusted by inflation).16

Consumption and expenditures among socioeconomic and demographic groupings of 

households, as well as geographic zones, differed markedly. For example, household with the 

presence of children (defined as those ages 17 and under) drove an additional 10 thousand miles 

and spent $650 more per year in 2001 than those without children. Households without children 

 

14 See http://www.eia.doe.gov/emeu/consumption/index.html; accessed July 28, 2005. 

15 8.3 million lane-miles. See Federal Highway Administration, Highway Statistics 2003 (U.S. Department of 

Transportation, Washington, DC) table HM-60. 

16 Energy Information Administration, Short-Term Energy Outlook. Accessed 

http://www.eia.doe.gov/emeu/steo/pub/contents.html on November 14, 2005. 
ENERGY OVERVIEW

purchased $1,241 worth of transportation fuel to drive 19.6 thousand miles versus $1,902 to drive

29.2 thousand miles for those households having children. 

Even though households are affected 

differently, their use, taken together,

contributes significantly to the nation’s

energy demands, especially the amount of 

petroleum products needed to move

people to and from places to acquire

goods and services, as the majority of 

vehicle engines are fueled with these 

products. In 2001, the United States 

consumed 113.1 billion gasolineequivalent gallons (GEG) to fuel 

passenger travel by light-duty vehicles, a

3.3 percent per year rise from 1994, when 

90.6 billion was consumed (see Figure 2). 

That fuel consumption by light-duty

vehicles, stored in a tank the size of a

regulation football field, would require

the tank to have walls nearly 50 miles high.17

Figure 2. Energy Consumption of Vehicles, Selected 

Survey Years 

80.3

83.9

82.4

82.8

90.6

113.1

0

20

40

60

80

100

120

1983 1985 1988 1991 1994 2001

Survey Year

Gasoline-Equivelent 

Gallons (billion)

Source: Energy Information Administration. 

DEMAND ANALYSIS TECHNIQUES 

Besides filling the data gap in consumer-based transportation statistics, this report addresses 

aspects of energy use on which consumers, policy and decision makers often focus – how

changing activity, structure, and intensity have affected the growth in energy use. Indeed, the

volatility of crude oil prices over the past year has focused attention on the economic condition of 

the oil and gas industry, the increasing the nation’s dependence on foreign oil supplies, and the 

prospects for reducing reliance on oil imports, all of which are affected to a high degree by 

transport’s intensity of use.

One family of demand analyses – index theory – decomposes value aggregates into their 

principal components, by examining changes in energy use over time by varying one component 

and holding all other components constant, a Laspeyres formulation of an index (see Figure 3). 

Because of its fundamental feature of decomposing aggregates, literature commonly refers to

these types of analyses as decomposition analysis. Initiated with the work by Boyd et al (1988)

which decomposed manufacturing energy use, economic and energy journals, as well as several 

economy-wide international works18, now offer a rich resource of literature on decomposition 

 17 A ft3

 equals 7.48 gallons. See www.ncaa.org/champadmin/football/football_field.gif for field dimensions. 

18 30 Years of Energy Use in IEA Countries: Oil Crises & Climate Change, International Energy Agency, (OECD/IEA,

Paris), 2004; Indicators of Energy Use and Efficiency: Understanding the Link Between Energy and Human Activity,

International Energy Agency, (OECD/IEA, Paris), 1997; and selected references under IEA’s indicator work include: 

Schipper, L., Unander, F., Murtishaw, S. and Ting, M. (2001). Indicators of Energy Use and Carbon Emissions: 

Explaining the Energy Economy Link, Annual Review of Energy and Environment, 26, 49-81; Unander F., Karbuz, S.,

Schipper, L., Khrushch, M., Ting, M. (2000). Manufacturing Energy Use in OECD Countries: Decomposition of LongTerm Trends, Energy Policy 27 (13): 769-778; Preston, J., Adler, R., Schipper, M. (1992). Energy Efficiency in the 

Manufacturing Sector, Monthly Energy Review, DOE/EIA-0035(1992/12). 

ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS 15
ENERGY OVERVIEW

results and techniques.19 Another technique (not used here) has been used by Golob and

Brownstone (2005) to show that a change in both vehicle-miles traveled and consumption per 

change in residential density was substantial for households in the State of California, comparing 

households by residential density, with all else being equal. 

Instead of linking residential density 

with energy use, changes in the structure

of households in terms of their 

composition (lifecycle); vehicle 

ownership; types of vehicles; activity in 

terms of travel, and vehicle fuel 

intensities (the inverse of fuel economy or

gasoline mileage) are linked to changing 

energy use, representing a few 

components offsetting or supporting the

surge in energy use to power vehicles’ 

engines. This report presents analysis on 

the effects for three time periods: 1988-

1991, 1991-1994 and 1994-2001. Both

the 1983 and 1985 RTECS are excluded

because key lifecycle information is only 

available from later surveys. Before analyzing those time periods, it is useful to identify 

variations in how Americans use energy based on the latest consumer data: the 2001 NHTS

augmented by EIA. 

Figure 3. Example of a Laspeyres Decomposition 

4

5

2

-3 -4

-2

0

2

4

6

Base Year to End Year

Annual Growth

(Percent)

Overall = Activity + Structure + Intensity

PREDICTORS OF ENERGY NEEDS 

EIA maintains a focused set of data programs and products, as a crucial part of its efforts to

inform and analyze national and international energy demand and supply, with strict adherence to 

neutrality. Many examine the energy delivered to end-use sectors from the top-down perspective 

of energy suppliers, while a few examine the energy used from the bottom-up perspective of 

energy consumers. Whether data originate from final consumers or not distinguishes these 

products. In most cases, EIA’s weekly, monthly, and annual data products are based on queries of

energy producers and transporters on their allocation of energy supplies, whereas less frequent 

but demographically rich data are based on surveys of some of the nation’s final consumers: 

households, manufacturing plants, commercial buildings, and, for this report, household vehicles. 

Less frequent studies focusing on final consumers serve as primary sources of predictors of 

energy needs and, in turn, demands made on energy supplies for purposes of producing 

manufacturing throughput, conditioning commercial square footage, and fueling passenger travel.

While acknowledging that end-use studies are artifacts of the year in which they are conducted, 

and recognizing that uncertainties remain due to infrequent implementation, summary measures 

 19 Ang, B.W. and Pandiyan, G. (1997). Decomposition of Energy-Induced CO2 Emissions in Manufacturing. Energy 

Economics, 19, 363-374; Boyd, G.A., Hanson, D.A., Sterner, T. (1988). Decomposition of Changes in Energy

Intensity: A Comparison of the Divisia Index and Other Methods, Energy Economics, 10, 309-312; Choi, K.H. and

Ang, B.W. (2003). Decomposition of Aggregate Energy Intensity Changes in Two Measures: Ratio and Difference,

Energy Economics, 25, 615-624; Huang, J. (1992). Industry Energy Use and Structural Change: A Case Study of The

People’s Republic of China, Energy Economics, 15(2), 131-136. 

16 ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS
ENERGY OVERVIEW

of energy demand are displayed in Tables 1 and 2 (including detailed tables in Appendix A), 

which present overall energy demand as 

Energy = f (Structure, Activity, Energy Intensity ). (1) 

Table 1. Measures of Energy Demand and Demand Activities, Selected Survey Years 

Survey Year

1983 1985 1988 1991 1994 2001

Number of Households (million) .......................................... 84.4 87.3 91.6 94.6 97.3 107.4 

Number of Households with Vehicles (million)................... 72.2 77.7 81.3 84.6 84.9 98.9 

Real Disposable Personal Income (chained billion $2000).. 4177.7 4645.2 5082.6 5351.7 5746.4 7333.3 

Population (million)............................................................... 233.8 237.9 244.5 252.2 260.3 285.1 

Number of Vehicles (million)................................................ 129.3 137.3 147.5 151.2 156.8 191.0 

Number of Vehicles per Household with Vehicles.............. 1.8 1.8 1.8 1.8 1.8 1.9 

Number of Vehicles per 1000 Capita................................... 555 577 603 600 602 670 

Vehicle-Miles Traveled (VMT) (billion) .............................. 1215 1353 1511 1602 1793 2287 

VMT per Household with Vehicles (thousand).................... 16.8 17.4 18.6 18.9 21.1 23.1 

VMT per Vehicle (thousand)................................................. 9.4 9.9 10.2 10.6 11.4 12.0 

Load Factor ........................................................................... 1.80 1.74 1.66 1.60 1.60 1.57 

Passenger-Miles Traveled (PMT) (billion) .......................... 2194 2354 2509 2564 2869 3591 

PMT per Household with Vehicles (thousand) .................... 30.2 30.3 30.9 30.2 33.8 36.3 

PMT per Vehicle (thousand) ................................................. 16.9 17.1 17.0 17.0 18.3 18.8 

Energy Intensity (equivalent gallons per 1000 miles)........... 66.2 62.1 54.6 51.8 50.5 49.5 

Gasoline-Equivalent Gallons (billion).................................. 80.3 83.9 82.4 82.8 90.6 113.1 

Sources: Energy Information Administration, Office of Energy Markets and End Uses, 1983, 1985, 1988, 1991, and 

1994 Residential Transportation Energy Consumption Surveys; Federal Highway Administration, U.S. Department of 

Transportation, 2001 National Household Travel Survey; U.S. Bureau of Economic Analysis, Table 2.1, Survey of 

Current Business Population, revised February 25, 2005; Oak Ridge National Laboratory (ORNL) under contract with 

the Office of Planning, Budget Formulation, and Analysis, under the Energy Efficiency and Renewable Energy (EERE) 

program in the U.S. Department of Energy (DOE), Transportation Energy Data Book: Edition 24. 

Note: * = a recession year. Estimates are displayed as rounded values. 

ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS 17
ENERGY OVERVIEW

Table 2. Annual Percent Change in Measures of Energy Demand, Selected Survey Years 

Survey-to-Survey Annual Percent Change

1983 

to 

1985

1985 

to 

1988

1988 

to 

1991

1991 

to 

1994

1994 

to 

2001

1983 

to 

2001 

Number of Households......................................................... 1.7 1.6 1.1 0.9 1.4 1.3 

Number of Households with Vehicles.................................. 3.7 1.5 1.3 0.1 2.2 1.8 

Population.............................................................................. 0.9 0.9 1.0 1.1 1.3 1.1 

Real Disposable Personal Income........................................ 5.4 3.0 1.7 2.4 3.5 3.2 

Number of Vehicles............................................................... 3.0 2.4 0.8 1.2 2.9 2.2 

Number of Vehicles per Household with Vehicles ............. 0.0 0.0 0.0 0.0 0.8 0.3 

Number of Vehicles per 1000 Capita................................... 2.0 1.5 (0.2) 0.1 1.5 1.1 

Vehicle-Miles Traveled (VMT)............................................ 5.4 3.8 2.0 3.8 3.5 3.6 

VMT per Household with Vehicles...................................... 1.8 2.2 0.5 3.7 1.3 1.8 

VMT per Vehicle................................................................... 2.6 1.0 1.3 2.5 0.7 1.4 

Load Factor ........................................................................... (1.7) (1.6) (1.2) 0.0 (0.3) (0.8) 

Passenger-Miles Traveled (PMT)........................................ 3.6 2.1 0.7 3.8 3.3 2.8 

PMT per Household with Vehicles...................................... 0.1 0.7 (0.7) 3.7 1.0 1.0 

PMT per Vehicle ................................................................... 0.7 (0.3) (0.1) 2.6 0.4 0.6 

Energy Intensity.................................................................... (3.2) (4.2) (1.8) (0.8) (0.3) (1.6) 

Gasoline-Equivalent Gallons................................................ 2.2 (0.6) 0.2 3.0 3.2 1.9 

Sources: Energy Information Administration, Office of Energy Markets and End Uses, 1983, 1985, 1988, 1991, and 

1994 Residential Transportation Energy Consumption Surveys; Federal Highway Administration, U.S. Department of 

Transportation, 2001 National Household Travel Survey; U.S. Bureau of Economic Analysis, Table 2.1, Survey of 

Current Business Population, revised February 25, 2005; Oak Ridge National Laboratory (ORNL) under contract with 

the Office of Planning, Budget Formulation, and Analysis, under the Energy Efficiency and Renewable Energy (EERE) 

program in the Department of Energy (DOE), Transportation Energy Data Book: Edition 24.

STRUCTURE 

Structure in transportation is defined as those characteristics that quantify and describe

vehicles available for use. 

Rest of the World Affects the U.S. 

Consumer 

While the relationship between

both population and housing growth

and energy is highly correlated,

research (Smil 2003; page 63) has 

concluded that the energy-economy

relationship, as measured in Total 

Primary Energy Supply and Gross 

Domestic Product (GDP), is neither 

linear nor simple; rather, it is 

dynamic and complex, precluding 

any normative conclusions among 

industrialized or developing

countries. 

HOUSEHOLDS WITH VEHICLES

In 2001 there were 107.4 million households in 

the United States, of which nearly 98.9 million (92 

percent) actually owned or possessed one or more 

vehicles, an increase of 1.8 percent per year from 

1983, 72.2 million out of 84.4 million households (86

percent) had possessed one or more vehicles. The

increasing number of households and a greater fraction 

of those possessing a vehicle, all else been equal,

should result in increased energy needs for the nation.

Decomposition analysis, given in later sections, shows 

this to be true. Indeed, no other predictor is as strong

in its link with energy use (see Text Box). 

18 ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS
ENERGY OVERVIEW

As evidenced by a parked car or a vacant,

shuttered residence, houses and vehicles neither

consume energy nor emit greenhouse gases on their

own; people do. They do so with the goal of obtaining

services in their homes and using vehicles for trips

(going to work, church, or obtaining food) in which 

goods or services are acquired. Thus, population, and 

especially the driving-age population, plays an

important role in predicting the number of households

with vehicles, number of vehicles and their resulting 

energy use. 

Rest of the World Affects the U.S. 

Consumer (continued) 

Yet, the confluence of economic 

growth and population does affect 

transport needs, and vice-versa. This

is readily apparent with developing

and emerging economies, especially

China’s and India’s as their

economic opportunities continue to

expand. 

The developing Chinese and

Indian economies, when pooled,

encompass half the world’s

population, but unlike the United

States, are nowhere close to any

saturation point and far below the 

POV mobility status seen among the 

U.S. and other industrialized

countries. As both seek higher 

mobility status (i.e., vehicles per 

capita), a rise similar to that of 

industrialized countries in the 

number of passenger vehicles, all

else remaining constant, would put 

significant upward pressure on 

global oil demands. 

Providing further interest to

automakers and policy makers, the 

Chinese, unlike the Indians, have

favored light-duty vehicles over twowheelers as the first-vehicle-ofchoice. 

The ratios of the number of vehicles per capita,

per driver, and per household suggest the nation had

reached a plateau from 1988 to 1994, when ratios were

nearly steady. After 1994, these ratios reinitiated their 

ascent, returning to the pre-1988 annual growth: 1.5

percent per year. Whether this restart was propelled by

the influence of economic growth and its impact on

household wealth and income is unknown; however, it 

arguably has played an important part. To date, unity 

has never been reached with any ratio discussed here.

NUMBER OF VEHICLES

As the use of two-wheelers versus passenger cars

is important when assessing POV trends in India and 

China, the number and types of vehicles operating on 

our nation’s roadways are just as important. In 2001, 

the average number of vehicles per household 

increased for the first time since 1983, from 1.8 

vehicles per household as reported by EIA in 1983,

1985, 1988, 1991, and 1994 to 1.9 vehicles (see Table 

1). In contrast, the average automobile occupancy, as 

measured by a load factor20, has continued its 

downward trend, albeit at a decreasing rate, in which

the annual percent change has been a negative 0.3 

percent, from 1.6 persons per vehicle in 1994 to 1.57 in 2001. Partially, this is a reflection of the

declines in household size, as population has increased at a slightly lower annual rate than 

housing.

 20 Oak Ridge National Laboratory (ORNL) under contract with the Office of Planning, Budget Formulation, and

Analysis, under the Energy Efficiency and Renewable Energy (EERE) program in the Department of Energy (DOE),

Transportation Energy Data Book: Edition 24. One hundred vehicle miles of travel with a vehicle load factor of 1.80 

persons is equivalent to 180 person-miles. If the occupancy falls to 1.57, then 180/1.57 vehicle miles of travel are

required for the same person-miles, a 15-percent increase in vehicle miles.

ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS 19
ENERGY OVERVIEW

Vehicle ownership varies among the nation’s households. Income and lifecycle (defined as 

the presence and age of children) are strong predictors of the number of vehicles per household 

(i.e., ownership). Income provides the means for vehicle ownership, while differing lifecycles

provide the motivation – thereby, creating pronounced ownership-lifecycle and ownershipincome links (see Figures 4 and 5). 

Average vehicle ownership rose in nearly every lifecycle category between 1994 and 2001.

Not surprisingly, households with children possessed, on average, more vehicles than those

without, and ones with a 16- or 17-year child yielded the highest ownership rate (2.6 vehicles per 

household); this is likely due in part to the effect of teenagers – 16- or 17-year-olds – who are 

becoming drivers. In 2001, such households recorded the highest vehicle ownership, with an

average of 2.6 vehicles per household, up from 2.4 vehicles in 1988, 1991, and 1994. Single-adult 

childless households registered the lowest vehicle ownership, consistently. Within those 

households, householders 60 years or older possessed the fewest number of vehicles per

household, possessing 1.1 vehicles in both 1994 and 2001. As more retirees return to the 

workforce, this trend may alter. Childless households with two or more adults, for instance, have 

reported an increase in average vehicle ownership, increasing 0.2 vehicles, from 1.8 in 1994 to 

2.0 vehicles in 2001. 

Figure 4. Vehicle Ownership by Household Composition (Lifecycle), Selected Survey Years 2.0 1.81.9 2.4 1.7 1.11.3 1.0 1.8 2.3 1.82.0 1.81.9 2.4 1.7 1.2 1.2 1.2 1.8 2.2 1.82.0 1.82.0 2.4 1.7 1.2 1.1 1.1 1.9 2.3 1.8 2.2 2.02.1 2.6 1.8 1.11.3 1.1 2.12.4

2.0

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Under

7

Years

7 to

15

Years

16 or

17

Years

Under

35

Years

35 to

59

Years

60

Years

or

Over

Under

35

Years

35 to

59

Years

60

Years

or

Over

Total Age of Oldest Child Total One Adult--Age of

Householder

Two or More Adults-

-Age of Householder

Households With Children Households Without Children

Vehicles per Household

1988 1991 1994 2001

Source: Energy Information Administration. 

Income also has a dramatic effect on vehicle ownership. Higher income translated into higher

ownership rates in 2001. Ownership at lower income levels (poverty or near poverty) is 

remarkably stable. There are, on average, 1.4 vehicles per household for those households having

a family income of less than $15 thousand. Moreover, though not universal, higher nominal

family income levels (i.e., $10,000 or more) correlate with steadily larger number of vehicles per

household, at a rate of about 0.1 additional vehicles per $5 thousand of additional income. 

20 ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS
ENERGY OVERVIEW

Figure 5. Vehicle Ownership by Nominal Family Income, 2001 1.4 1.4 1.41.51.61.7

2.0

2.1

2.5

1.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Less than

$5,000

$5,000 to

$9,999

$10,000 to

$14,999

$15,000 to

$19,999

$20,000 to

$24,999

$25,000 to

$34,999

$35,000 to

$49,999

$50,000 to

$74,999

$75,000 or

Mor

e

Don't

Know

Nominal Family Income

O

wnership (Vehicles per Household)

Source: Energy Information Administration, tables in this report. 

TYPES OF VEHICLES

Americans have demonstrated a preference in the vehicles they purchase for their travel 

needs. New vehicle sales suggest a shifting in vehicle preference away from passenger cars as 

automakers introduced and intensely marketed sports-utility vehicles (SUVs).21 They are 

increasing in popularity as passenger cars (including cars and stations wagons) are declining in 

market share of the new light-duty vehicle market. In 2004, SUVs captured 26 percent (4.3 

million of the 16.6 million light-duty sales) of the new vehicle market, up from 11 percent (1.6 

million of the 14.0 million light-duty sales) in 1994. Passenger cars accounted for 52 percent (8.6 

million); vans accounted for 7.0 percent (1.2 million); and, pickups accounted for 15 percent (2.5

million) of the remaining vehicles sold in 2004 (see Figure 6). 

Even though SUVs are increasingly popular among Americans, passenger cars still rank as 

their overall vehicle of choice, as they make up the majority of vehicles on America’s roadways. 

Cars, including station wagons, represented just over 50 percent of new vehicle purchases in

2001, according to the sales figures from EPA’s latest Fuel Economy Trends report, though in 

each of the subsequent years they have lost market share to SUVs. As of 2001, a recession year,

the distribution of sales and scrappage rates had resulted in a household vehicle fleet of 191.0

million vehicles: 112.4 million (58 percent) passenger cars, 18.4 million (10 percent) vans, 23.2 

million (12 percent) SUVs, 35.6 million (19 percent) pickups, and 1.4 million (1 percent) 

recreational vehicles (see Figure 7). 

 21 How consumers chose vehicles and their components follows a complex decision process which is beyond the scope 

of this report. 

ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS 21
ENERGY OVERVIEW

Figure 6. Number and Share of New Vehicles Sold in the United States by Vehicle Type and Year 8.29.711.3 11.2 10.8 9.4 8.7 7.8 8.010.7 10.8 11.0 10.7 10.7 10.0 8.8 8.5 8.18.5 8.49.4 7.98.3 8.08.49.1 8.4 8.3 7.78.6

0

5

10

15

20

1975*

1976197719781979

1980*1981*1982*

1983198419851986198719881989

1990*1991*

199219931994199519961997199819992000

2001*

200220032004

Model Year

New Light-Duty Vehicle Sales (million)

Passenger Cars Vans SUVs Pickups

Source: U.S. Environmental Protection Agency, Fuel Economy Trends, 2004; Note * = recession year. 

Figure 7. Distribution of Vehicle Stock, 2001 112.4 18.4

23.2

35.6

1.4

0.0

25.0

50.0

75.0

100.0

125.0

2001

Number of Vehicles (million)

Passenger Cars Vans

SUVs Pickups

Recreation Vehicles

Source: Energy Information Administration, tables in this report. 

22 ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS
ENERGY OVERVIEW

ACTIVITY 

Activity reflects the use of vehicles, as measured by annual vehicle-miles traveled, average 

number of trips per year, and average trip distances. 

VEHICLE-MILES TRAVELED

Travel activity (How many miles do the nation’s vehicles travel?) is a key factor in 

determining motor fuel consumption, roadway congestion and impacts on the environment. In an 

environment of little-to-no change in gasoline mileage, energy use is directly proportional to 

travel; and, likewise, most emissions are directly proportional to energy use. In 2001, light-duty

vehicles accumulated over 2.2 trillion vehicle-miles, up 3.5 percent per year from 1994, when 

EIA reported that light-duty vehicles traveled 1.8 trillion vehicle-miles. For perspective, that’s 

enough miles to travel 25,000 times between the Sun and the Earth.

22 

Over time, numerous factors have affected travel activity, though the presence of children in 

a household has continued to show a sharp effect. In 2001, average household driving varied 

extensively depending on the makeup (i.e., lifecycle) of a household: 

• Households with children averaged 29.2 thousand miles compared with 19.6

thousand miles in households with no children; 

• Households with 16- or 17-year-olds children drove more than any other (34.0

thousand miles), about 6 thousand miles more than households with younger

children; 

• For households without children, vehicle-miles traveled ranged from 12 thousand

miles in single-adult households to 24.8 thousand miles in households with two or 

more adults; and, 

• For single-driver households without children, vehicle-miles traveled ranged from a 

low of 8.0 thousand miles for drivers at least 60 years of age to 14.4 thousand miles

for drivers under 35 years of age. 

Roadway congestion affects all households, and it is a growing problem in urban areas. 

Congestion (defined by the relationship between urban vehicle-miles traveled and urban road

miles or urban throughput) on the nation’s roadways has risen, as evidenced by urban road miles 

increasing 36 percent between 1980 and 2000, while urban vehicle-miles traveled increased 95 

percent.23

 22 An Astronomical Unit is the average distance between the Sun and the Earth. Its value is 149,597,870 km (93 million

miles). 

23 U.S. Department of Transportation, Federal Highway Administration. Accessed on the world-wide web at 

http://www.fhwa.dot.gov/environment/cmaqpgs/amaq/03cmaq1fig3.htm on July 11, 2005. 

ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS 23
ENERGY OVERVIEW

24 ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS

ONE-WAY TRIPS PER YEAR AND AVERAGE ONE-WAY TRIP DISTANCES

Yet, neither congestion nor higher prices have frustrated motorists to the extent that travel 

plans have been disrupted, as year-to-year demand for total transport fuel continues to increase 

even as prices continue to rise; survey-to-survey load factors have declined; and, survey-tosurvey trip24 lengths have increased to their highest levels since 1990 (see Figures 8 and 9). Such 

national statistics provide evidence that behavior changes are slow to come about, because 

vehicle stock changes occur slowly and Americans still need to carry out their lives, traveling 

back and forth to work, church, or the local grocery store as needed. Figure 10 provides further 

explanation: depressed motor gasoline prices coupled with a steady rise in income. 

Figure 8. Average Vehicle Trip Length, Selected 

Survey Years 8.9

11.0

5.1

7.4

11.8

9.1

11.8

5.6

6.9

11.2

9.9

12.1

6.7

7.5

11.9

0

2

4

6

8

10

12

14

All

To/From

Work

Shopping

Other

Social

Purpose

Average Trip Length (miles)

1990 1995 2001

Source: Federal Highway Administration, 

Summary of Travel Trends (December 2004). 

Figure 9. Average Annual Vehicle Trips per 

Household, Selected Survey Years 2,077 448 431579

460

2,321

553

501

626

427

2,171

479

459

537

441

0

500

1,000

1,500

2,000

2,500

All

To/From

Work

Shopping

Other

Social

Purpose

Average Annual Trips

1990 1995 2001

Source: Federal Highway Administration, 

Summary of Travel Trends (December 2004). 

Whether American consumers are immune to price increases or any change in vehicle stock 

or travel heretofore is not sufficient to affect travel, it is seemingly inevitable that price signals, if 

the price of gasoline moves sharply higher than previously experienced, should generate a 

measurable change in travel behavior.25

 

24 A trip is defined as any time the respondent went from one address to another by private motor vehicle, public 

transportation, bicycle, walking, or other means. A trip purpose is the main reason that motivates a trip. 

25 “The energy intensity of the United States economy has been reduced by about half since the early 1970s in response 

to sharply higher prices. Much of the displacement was achieved by 1985. Progress in reducing energy intensity has 

continued since then, but at a lessened pace. This more-modest rate of decline in intensity should not be surprising, 

given the generally lower level of real oil prices that prevailed between 1985 and 2000. With real energy prices again 

on the rise, more rapid decreases in the intensity of use in the years ahead seem virtually inevitable." Quoted from a 

speech by Allan Greenspan, Chairman, U.S. Federal Reserves (April 5, 2005). 
ENERGY OVERVIEW

As gasoline prices rise on the heels of a decade or more of depressed prices, what are the 

signals to which consumers have been listening? While the real retail price of gasoline has risen 

and fallen over the past two decades, there has been an overall decline of 1.3 percent per year 

between 1983 and 2001, with substantial drops in 1986 and 1998 and somewhat smaller ones in

1991 and 2001 (see Figure E1 for a Chronology of World Oil Prices). In contrast, the prices of

other consumer products26 have risen dramatically, taking a higher real percentage of consumers’

budgets (see Figure 10). Given the minor role fuel prices have played in determining vehicle use,

there is little surprise that vehicle-miles traveled is better correlated with disposable income than 

retail prices; furthermore, the improvement in energy intensity, though unexceptional, might have 

further weakened a diminished price signal by mitigating the effect of fuel prices, where 

consumers could travel further on $1 of transportation fuel. Given that retail price is primarily 

based on the price paid for crude oil27, price signals to consumers should mimic world crude oil

prices, which have exceeded $50 per barrel (bbl) – at times surpassing $60 per bbl. 

Retail prices include Federal, State, and Local excise taxes. Hence, fuel taxes represent yet 

another signal to consumers. Federal excise taxes are 18.4 cents per gallon and State excise taxes 

average about 21 cents per gallon.28 Since 1988, Federal and State excise taxes on gasoline have 

been collected at the wholesale level, not the retail level. This means that retailers must pay all 

taxes at the terminal29 when they purchase fuel through a truckload sale. This protects the U.S. 

Treasury from missing any uncollected taxes and any need to conduct audits of gas station 

owners. It is the retailers' responsibility to recover their expense; that is why when the consumer 

purchases fuel they see only the total cost. The retailer is not remitting any funds to a 

governmental entity when a consumer makes a purchase; consequently, final purchase receipts 

exclude any listing of fuel tax . Though consumers would still react to retail prices, uncertainty 

exists with the measured impact from excise taxes, as the lack of visibility might partially dampen 

the impact such taxes could have on the demand for gasoline. 

Besides fuel price, which signals do consumers recognize? Statistically, real disposable 

income30 is one such signal. Based on 1983, 1985, 1988, 1991, 1994, and 2001 point estimates, it

can explain 99 percent of the variation in vehicle-miles traveled. From such a result, it could be

argued that the change in vehicle-miles per unit change of real disposable income, as measured in 

chained dollars, is 0.3, the estimate of the slope, β1, of the regression Y = β0 + β1X, with Y

denoting travel and X denoting real disposable income. Since 1983, with some minor deviations, 

the growth in vehicle-miles traveled has mirrored the increases in real disposable income. For 

instance, between 1983 and 1985, when annual real gasoline prices dropped 4.4 percent per year,

 26 See components of the Consumer Price Index conducted by the U.S. Bureau of Labor Statistics. 

27 See Federal Trade Commission, Gasoline Price Changes: the Dynamic of Supply, Demand, and Competition, July 5, 

2005, Washington, DC. Accessed http://www.ftc.gov/opa/2005/07/gaspricefactor.htm on July 25, 2005. 

28 See Energy Information Administration, Petroleum Marketing Monthly June 2004, Table EN1. Note: 90 percent or

more of Federal excise taxes are returned to States. 

29 Terminal, or "rack" – sales of product by the truckload (typically about 8,000 gallons) at the loading rack of a 

product terminal, supplied from a refinery, pipeline, or port. 

30 Total after-tax income, as measured in chained dollars, received by persons; it is the income available to persons for 

spending or saving. 

ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS 25
ENERGY OVERVIEW

the annual growth of vehicle-miles traveled (i.e., overall travel) and disposable income rose 5.4 

and 5.5 percent, respectively. Despite some inconsistencies when travel activity grew faster than 

disposable income, their overall growth between 1983 and 2001 is in near lock-step formation,

with real disposable income registering a rise of 3.2 percent per year and travel activity growing

at an annual rate of 3.6 percent. 

Figure 10. Annual Indices of Real Disposable Income, Vehicle-Miles Traveled, Consumer Price Index

(CPI-U), and Real Average Retail Gasoline Price, 1978-2004, 1985=100

0

20

40

60

80

100

120

140

160

180

200

1977197819791980

1981*1982*

1983198419851986198719881989

1990*1991*

199219931994199519961997199819992000

2001*

200220032004

Index (1985=100)

Real Disposable Personal Income

Real Motor Gasoline Price for All Grades

Vehicle-Miles Traveled

CPI-U: All items less food and energy

Sources: Energy Information Administration, Annual Energy Review 2004; Bureau of Economic Analysis. 

Note * = recession year.

ENERGY INTENSITY 

Energy intensity indicates the energy performance of the nation’s vehicle stock. 

ENERGY PERFORMANCE: GALLONS PER VEHICLE-MILE TRAVELED

Tracking an economy’s energy intensity – its energy performance – as the ratio of energy per 

GDP (or the environmentally based intensity of carbon dioxide per GDP31) is common in energy 

economics, and such a technique can be applied to transport. Instead of a ratio of economy-wide 

energy use per GDP, one can use a ratio of gasoline-equivalent gallons (GEG) per vehicle-miles 

traveled for the entire vehicle stock (see Figures 11-14). This intensity has steadily improved

since 1983, though the greatest strives toward lowering (improving) energy intensity had 

occurred before 1991. Post-1991 improvements (i.e., energy performance) slowed dramatically,

yielding an overall annual improvement of 1.6 percent between 1983 and 2001, as compared to

the 3.2 and 4.2 percent gains seen in the 1983-1985 and 1985-1988 time periods, respectively. 

No other vehicle energy predictor seems to draw as much public scrutiny. There is some

justification behind this: it is one of the most visible measures used by decision and policy makers 

to regulate energy use and consumers to identify a vehicle’s energy performance. From “stickers”

 31 Greenhouse gas emissions from petroleum-powered vehicles are directly proportionally to energy use. 

26 ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS
ENERGY OVERVIEW

on each new vehicle to identify its on-road fuel economy and the joint publication of fuel

economies by the U.S. DOE and U.S. EPA at www.fueleconomy.gov to the Gas Guzzler tax

(USC 26 § 4064) based on these same “sticker” values and NHTSA’s Corporate Average Fuel 

Economy (CAFE) program, progress on energy intensity (measured as GEG per mile), the 

inverse of fuel economy (measured as miles per GEG) is one measure of which the public is

highly informed and concerned, where even the plans to revise EPA’s measurement tests for 

determining on-road fuel economy create national interest.32

Figure 11. Sales-Weighted On-Road Fuel Economy 

by Vehicle Type, 1975-2004 Model Years

10

12

14

16

18

20

22

24

26

1975 1980 1985 1990 1995 2000

Miles per Gallon

Source: U.S. Environmental Protection Agency, Fuel 

Economy Trends 2004. 

Figure 12. Average On-Road, In-Use Fuel Economy 

by Vehicle Type, 200123.4

19.1

17.0

17.2

10

12

14

16

18

20

22

24

26

2001 Vehicle Stock

Miles per Gallon

Source: Energy Information Administration, tables in 

this report. 

Figure 13. Sales-Weighted On-Road Energy Intensity

by Vehicle Type, 1975-2004 Model Years

0

20

40

60

80

100

1975 1980 1985 1990 1995 2000

Gallons per 1000 Miles

Source: U.S. Environmental Protection Agency, Fuel 

Economy Trends 2004. 

Figure 14. Average On-Road, In-Use Energy 

Intensity by Vehicle Type, 2001 42.7 52.4

58.8

58.1

0

20

40

60

80

100

2001 Vehicle Stock

Gallons per 1000 Miles

Source: Energy Information Administration, tables in 

this report. 

Passenger Cars Vans

SUVs Pickup Trucks

Passenger Cars Vans

SUVs Pickups

 32 See Fialka, J., The Wall Street Journal; page D1, May 12, 2005. 

ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS 27
ENERGY OVERVIEW

While changes in energy intensity are often used to suggest efficiency, care should be used to 

avoid any confusion with technical efficiency and economic efficiency. Technical efficiency is 

where the maximum output is achieved with minimal input; economic efficiency is the

production and distribution of goods or services at the lowest possible cost. Thus, technical 

efficiency is not necessarily a sufficient condition for economic efficiency, or vice-versa. For 

example, an engine developed for superior technical efficiency might require a fuel that utterly

violates economic efficiency; and an economically efficient engine might be far from technically

efficient. 

Propulsion efficiency of jet engines is one technology area in which technical efficiency 

seems to have gone hand-in-hand with economic efficiency, as the ratio of thrust-aircraft velocity 

per heat added has steadily improved.33 This efficacy, especially with respect to thrust, has 

enabled larger aircraft for airline passenger travel, all at a significant decrease in heat added,

which translates into less fuel consumed per passenger-mile.34

Propulsion efficiency of vehicles has trod a highly similar path; engine efficacy (as suggested 

by horsepower (HP)) of each succeeding models years has generally increased, as suggested by

the trajectories of the sales-weighted on-road fuel economy values presented in Figures 17, 19, 

21, and 23. For a number of reasons beyond the scope of this report, that progress mostly 

excluded improvements in energy intensity, as energy performance (as measured by energy 

intensity) only slightly improved. Even though automakers have continued to make

improvements in technology, “consumer preference over the past 15 or 20 years has led 

automakers to increase vehicle size, weight, and horsepower while holding gasoline mileage [the

inverse of energy intensity] more or less constant,” though vans do show some improvement (see 

Figures 18, 20, 22, and 24).

35 As load factors for vehicles deteriorated over the 1983 to 2001 time 

period, fewer people were transported in heavier, more powerful, slightly more-fuel-efficient

vehicles. 

Automakers did increase vehicles’ energy performance but that has been offset by 

consumers’ increased travel needs. Energy intensity improved 1.6 percent per year, from 66.2

GEG per 1000 miles in 1983 to 49.5 GEG in 2001, while per-vehicle travel offset this 

improvement by increasing 1.4 percent per year, from 9.4 thousand miles per vehicle to 12.0 

thousand miles, as the number of vehicles in total increased 2.2 percent per year – simply put,

more vehicles are traveling farther. Hence, travel activity is a much better predictor of future 

energy needs than energy intensity, as fuel economy of vehicles sold in America is relatively 

stable, though pickups do exhibit a trajectory of declining sales-weighted fuel economy.

 33 Edwards, C.F., Technological Potential and Challenges to Low GHG Transportation, International Petroleum IPECA

Transportation and Climate Change Conference, October 13, 2004. See http://www.ipieca.org/ for details.

34 Mattingly, J.D., Elements of Gas Turbine Propulsion, McGraw Hill (1996), as presented by C.F. Edwards at the 

IPIECA Transportation and Climate Change Conference, October 13, 2004. 

35 See Congress of the United States, Congressional Budget Office, The Economic Costs of Fuel Economy Standards 

Versus a Gasoline Tax, December 2003. 

28 ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS
ENERGY OVERVIEW

Figure 15. Average On-Road, In-Use Energy 

Intensity, Selected Survey Years 66.2 62.1 54.6

51.8

50.5

49.5

0

20

40

60

80

1983 1985 1988 1991 1994 2001

Survey Year

Gallons per 1000 Miles

Source: Energy Information Administration. 

Figure 16. Average Vehicle-Miles Traveled per 

Vehicle, Selected Survey Years 9.49.9 10.2

10.6

11.4

12.0

0

5

10

15

1983 1985 1988 1991 1994 2001

Survey Year

Miles per Vehicle 

(thousand)

Source: Energy Information Administration. 

Is this increased travel an effect of the exurbanization in America and its associated upward 

pressure on increased trip lengths? Are Americans increasingly on the move? How much does 

vehicles’ energy performance and Americans’ travel affect overall energy use? Decomposition 

analysis provides some answers for the latter questions, while the first is decidedly more 

intractable given the lack of sub-national data on travel and energy use. 

ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS 29
ENERGY OVERVIEW

Figure 17. Sales-Weighted Horsepower and On-Road Fuel Economy for Passenger Cars, 1975-2004 

Model Years 

1975 19761977

1978

1979

1980 1981 1982

19831984

1985 1986 1987

1988

1989

1990

1991

19921993

1994

199 19956 1997 1998

1999

2002001 0

2002

2003

2004

90

100

110

120

130

140

150

160

170

180

190

10 12 14 16 18 20 22 24 26

Miles Per Gallon

HP

Source: U.S. Environmental Protection Agency, Fuel Economy Trends 2004.

Figure 18. Sales-Weighted Vehicle Weight and On-Road Fuel Economy for Passenger Cars, 1975-2004

Model Years 

1975 1976

1977

1978

1979

1980 1981

1982

198319841985

1986 1987

1988

1989

1990 1991

19921993

1994 199 199756 1998

199 2002001 2002 90

2003 2004

2900

3100

3300

3500

3700

3900

4100

10 12 14 16 18 20 22 24 26

Miles Per Gallon

Inertia Weight

Source: U.S. Environmental Protection Agency, Fuel Economy Trends 2004.

30 ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS
ENERGY OVERVIEW

Figure 19. Sales-Weighted Horsepower and On-Road Fuel Economy for Vans, 1975-2004 Model Years 

1975 1976

1977 1978

1979

1980 1981 19821983

19841985 1986

1987

1988 1989 1990 1991 19921993 1994 1995

1996 1997

1998 19992000

2001

2002

20032004

90

110

130

150

170

190

210

230

10 12 14 16 18 20 22

Miles Per Gallon

HP

Source: U.S. Environmental Protection Agency, Fuel Economy Trends 2004.

Figure 20. Sales-Weighted Vehicle Weight and On-Road Fuel Economy for Vans, 1975-2004 Model 

Years 

1975 1976

19781977

1979

1980

1981 1982

1983

1984

1985 1986

1987

11988 989

1990

1991 1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

3900

4000

4100

4200

4300

4400

4500

4600

10 12 14 16 18 20 22

Miles Per Gallon

Ineria Weight

Source: U.S. Environmental Protection Agency, Fuel Economy Trends 2004.

ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS 31
ENERGY OVERVIEW

Figure 21. Sales-Weighted Horsepower and On-Road Fuel Economy for SUVs, 1975-2004 Model Years 

1975 1976 1977

1978

1979

1980 1981 1982 19831984 19851986

1987

1988

1990 19891991

1992

19941993 1995

1996 1997 1998

1999 2000

2001

20022003

2004

90

110

130

150

170

190

210

230

250

10 11 12 13 14 15 16 17 18 19

Miles Per Gallon

HP

Source: U.S. Environmental Protection Agency, Fuel Economy Trends 2004.

Figure 22. Sales-Weighted Vehicle Weight and On-Road Fuel Economy for SUVs, 1975-2004 Model 

Years 

1975

1976

1977

1978

1979

1980 1981

1982

1983

1984 1985

1986

1987 1988

1989 19901991 1992

1993

1994 19951996

1997 1998

1999

20002001

2002

2003 2004

3700

3800

3900

4000

4100

4200

4300

4400

4500

4600

4700

10 11 12 13 14 15 16 17 18 19

Miles Per Gallon

Inertia Weight

Source: U.S. Environmental Protection Agency, Fuel Economy Trends 2004.

32 ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS
ENERGY OVERVIEW

Figure 23. Sales-Weighted Horsepower and On-Road Fuel Economy for Pickups, 1975-2004 Model Years 

19751976 19781977

1979

1980 1981 1982 1984 1983

1985 19861987

1988 1989

1990 1991 1992 1993

1994 1995

1996

1997 1998

19992000

2001

20022003

2004

90

110

130

150

170

190

210

230

250

270

10 11 12 13 14 15 16 17 18 19 20

Miles Per Gallon

HP

Source: U.S. Environmental Protection Agency, Fuel Economy Trends 2004.

Figure 24. Sales-Weighted Vehicle Weight and On-Road Fuel Economy for Pickups, 1975-2004 Model

Years 

1975

1976 19781977 1979

1980

1981 1982

1983

1984 1985

19861987

1988

1989

1990

1991

1992 1993

1994

1991996 5

1997

1998

1999

2000

2001

2002

2003

2004

3400

3600

3800

4000

4200

4400

4600

4800

5000

10 11 12 13 14 15 16 17 18 19 20

Miles Per Gallon

Weight

Source: U.S. Environmental Protection Agency, Fuel Economy Trends 2004.

ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS 33
ENERGY OVERVIEW

DECOMPOSING ENERGY NEEDS 

Decomposition analysis is a logical means to link 

changes structure, activity and energy intensity to

changes in energy use. These links should not to be 

confused with total energy efficiency, economic or 

technical efficiency to changes in energy use. To 

decompose energy use, a few of the demand predictors 

available in this report are linked to energy, effectively 

creating structure-energy, activity-energy, and 

intensity-energy links. 

Unfortunately, restrictions on the data limit the 

scope of this work. Had greater sample sizes been

available in the RTECS conducted in 1983 through 

1994, it might have been possible to analytically link a 

wider array of measures. The sample sizes of RTECS,

though, rarely supported point estimates crossed on 

more than a few characteristics. Because survey

sample sizes – generally on the order of 3,000 

households and 6,000 vehicles – become exceedingly 

thin as one calculates energy and energy-related

statistics by household and vehicle characteristics – 

such as lifecycle, vehicle type, geographic region (e.g., 

urban versus rural), and income – decomposition of 

energy needs is limited to only a few key components 

(see Tables 4 through 9). 

Decomposition is a means of analyzing an overall 

change over time. The key is identifying intermediate 

predictors that are measurable and dimensionally

intertwined with each other in ratios such that an

overall statistic can be "decomposed" into the product 

of two or more "effects," effectively linking them 

together. It is then possible to examine a change over

time in the overall statistics (in this case, energy use)

in terms of changes in the component ratios. Note that 

the use of the term “predictor” has been replaced by

“effect” to emphasize that conclusions are statistical in 

nature, not causal. The multiplied components in 

Equation 2 are one example of the decomposition

process. 

Key Terms 

These terms and general

formulation for quantifying 

concluding effects on the changes in 

energy use were adapted from Oil 

Crises & Climate Challenges: 30 

Years of Energy Use in IEA

Countries, an economy-wide 

decomposition conducted by the 

Paris-based International Energy

Agency, using Laspeyeres indices. 

Activity: Basic unit of 

accounting for which energy

is used, which, in this report, 

is the amount of travel, as 

measured by miles per vehicle. 

Energy Intensity: Energy 

consumed per unit of activity; 

gasoline-equivalent gallons

per vehicle-mile traveled, as 

measured on-road and in-use.. 

Structure: Refers to the mix of 

activities within the residential 

transportation sector; for 

example, number of 

households, fraction of

housing belonging to a given 

lifecycle category, average 

number of vehicles owned per 

household, and fraction of

vehicles in the nation’s vehicle 

stock by type.

= • ∑ • • ∑ • ∑ • • ⎟

⎟

⎠

⎞

⎜

⎜

⎝

⎛

⎟

⎟

⎠

⎞

⎜

⎜

⎝

⎛

⎟

⎟

⎠

⎞

⎜

⎜

⎝

⎛

i k Milesijk

Gallonsijk

Vehiclesijk

Milesijk

Vehiclesij

Vehiclesijk

j Vehiclesi

Vehiclesij

Householdsi

Vehiclesi

Households

Householdsi

Gallons Households

.. .

.

..

.. ..

K K K (2) 

Equation 3 presents a simplified form of Equation 2. 

34 ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS
ENERGY OVERVIEW

Milesijk

Gallonsijk

Vehiclesijk

Milesijk

Vehiclesij

Vehiclesijk

Vehiclesi

Vehiclesij

Householdsi

Vehiclesi

i j k Households

Householdsi Gallons = Households • ∑ ∑ ∑ • • • • •

.. .

.

..

.. ..

K K K (3)

where i denotes a household lifecycle (up to 9 categories), j denotes vehicle type (up to 4 

types), and k identifies a vintage category of vehicles (up to 2 categories). In the following 

analysis, combinations of years of survey data, household lifecycle, vehicle type, and vintage are 

explored to partition the overall change in energy needs. To avoid any confusion with the 

combinations, a mnemonic – Decomposition # Survey Years # Lifecycles # Vehicle Types #

Vintages – serves to identify each combination under analysis. 

• Decomposition 4942 represents a decomposition covering 4 years of survey data, 9

categories of household lifecycle, 4 vehicle types and 2 vintage groupings (new 

versus old); 

• Decomposition 4941 represents a decomposition covering 4 years of survey data, 9

categories of household lifecycle, 4 vehicle types, and no vintage categorization; and 

• Decomposition 4921 represents a decomposition covering 4 years of survey data, 9

categories of household lifecycle, 2 vehicle types (e.g., cars versus all other vehicle

types) and no categorization of vintage. 

Using EIA data, seventy-two (9 x 4 x 2) separate decompositions can be completed for each

base and end year combination. Because most of those decompositions give similar results, only a 

few have been completed and displayed.

In decompositions found herein, 4 years of survey data – 1988, 1991, 1994, and 2001 – are 

deemed eligible for use because necessary data (e.g., household lifecycle details) were not 

obtained in 1983 and 1985. For vehicle-possessing households, lifecycles are restricted to 9 

categories: 

1. Age of oldest child is younger than 7 years of age, 

2. Age of oldest child is 7 to 15 years, 

3. Age of oldest child is 16 or 17 years, 

4. Householder is younger than 35 years in a household with one adult and no children, 

5. Householder is 35 to 59 years of age in a household with one adult and no children, 

6. Householder is 60 years or older in a household with one adult and no children,

7. Householder is younger than 35 years in a household with two or more adults and no 

children, 

8. Householder is 35 to 59 years of age in a household with two or more adults and no

children, and 

ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS 35
ENERGY OVERVIEW

9. Householder is 60 years or older in a household with two or more adults and no 

children. 

Vehicle types are grouped as passenger cars, vans, SUVs, and pickups (defined as

recreational vehicles and pickup trucks).

MEASURING AN EFFECT 

To assess the effects of each component, one only needs to calculate the ratio of the overall

energy use based on varying only one component (activity, structure, or energy intensity) to the 

actual amount in a given year. This is typically done using the earlier year (base year) for

comparison. For example, the energy intensity effect is assessed for a base year, 0, and end year, 

t, by the following: 

Gallons Activity Structure Intensity

Intensityt Gallons Activity Structure t

0 , 0 , 0 0

, 0 ,

0 Energy Intensity Effect

K

K = (4)

Base years given herein are 1988, 1991, or 1994. They are denoted as 0; while an end year (t) 

is defined as any survey fielded in a succeeding year (e.g., 1991 for 1988, 1994 for 1991 and so 

on). 

Given the formulation of the Energy Intensity Effect denoted in Equation 4, calculations are 

analogous for the other remaining effects: 

• Housing Effect, 

• Lifecycle Effect, 

• Ownership Effect, 

• Vehicle Type Effect, 

• Vintage Effect, and 

• Vehicle Use Effect. 

Interactions are difficult to interpret, because they represent all possible combinations of the

above listed effects. Typically, Interactions are minor and may, in some analyses, be excluded 

from calculation, because they can be calculated by subtraction. As evidence of the minor 

interactions among effects, literature has shown that vehicle travel is relatively insensitive to

energy intensity improvements, explaining that a “10 percent increase in fuel economy would 

lead to a 1 to 2 percent increase in vehicle travel.”36 For completeness, all Interaction Effects, 

though small, are displayed in this report. The limited ability to interpret interactions is 

commonly cited as a justification for using Divisia Indices, rather than Laspeyres. Given the 

 36 Greene, D. and Schafer, A., Reducing Greenhouse Gas Emissions from U.S. Transportation, Pew Center, May 2003. 

36 ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS
ENERGY OVERVIEW

small contributions from Interactions during the time periods of interest, especially after

annualizing its value to make assessments, the Laspeyres computation is used in this report. 

Figure 25. Decomposition 4942 of Energy Needs, 1988 and 2001

2.46

1.52

-0.01

0.49 0.42

-0.01

1.19

-1.20

0.06

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Annual Percent Growth

Source: Calculated by Energy Information Administration. 

Figure 26. Energy Savings from Energy Intensity Effect, 2001 

113.1

19.2

0

20

40

60

80

100

120

140

Use based on energy intensity at 1988, all else

fixed at 2001

G

E

G (billion)

Source: Calculated by Energy Information Administration. 

Decomposition 4942

2.46 PERCENT PER YEAR

OVERALL ENERGY GROWTH

1.52 PERCENT PER YEAR 

HOUSING EFFECT

-0.01 PERCENT PER YEAR 

LIFECYCLE EFFECT

0.49 PERCENT PER YEAR 

OWNERSHIP EFFECT

0.42 PERCENT PER YEAR 

VEHICLE TYPE EFFECT

-0.01 PERCENT PER YEAR 

VINTAGE EFFECT

1.19 PERCENT PER YEAR 

VEHICLE USE EFFECT

-1.20 PERCENT PER YEAR 

ENERGY INTENSITY EFFECT

0.06 PERCENT PER YEAR 

INTERACTIONS

Concluded Energy Savings 

based on the Intensity Effect

19.2 million gasolineequivalent gallons (GEG)

SUMMARY OF DECOMPOSTION 4942

Decomposition provides a cleaner view of changes in energy use, helping to quantify effects

and drive further analyses by assessing the relative importance of each component. First, the

vehicle vintage shows limited impact on the change in energy use, meaning the proportion of 

vehicles, by vintage categories, is unchanging from survey to survey, as no variation in energy

use is readily detectable by Equation 4, which calculates a -0.01 percent per year effect for 

Vintage. Based on vehicle sales figures and assuming a steady-state in the scrappage of vehicles,

it is not surprising that vintage is less important to the nation’s energy use than energy intensity, 

given that the sales figures for the past decade show that the nation’s yearly purchases averaged 

15.2 million vehicles with a standard deviation of 1.1 million vehicles, meaning new vehicle sales 

levels have been relatively constant, even for the 2001 recession year. Vintage categories,

ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS 37
ENERGY OVERVIEW

therefore, are dropped for all remaining decomposition analyses, which are denoted as 

Decomposition ###1. 

Second, the Energy Intensity Effect (-1.2 percent per year) played a significant part in

reducing the nation’s energy use between 1988 and 2001. That improvement, however, was offset

by 1 activity and 3 structural effects: Vehicle Use (1.19 percent), Housing (1.52 percent),

Ownership (0.49 percent), and Vehicle Type (0.42 percent) – combined, they account for 3.61

percent per year growth in energy use. Even though the Lifecycle Effect is seemingly equivalent

to the minimal influence shown by vehicle vintages, this effect is carried forward to further 

analyses because of the substantial changes occurring in the nation’s population mix, such as the 

elderly tending to stay closer to their family members.37 

Energy savings is one measure that quantifies the Energy Intensity Effect. The IEA defines

concluded “energy savings” as the difference between the hypothetical amount of energy that 

would have been used in a given year if energy intensities had remained at base-year values and

the actual energy use. From 1988 to 2001, the improvement in energy intensity, all else being

equal, would have resulted in an energy savings of 19.2 billion gallons, meaning the nation would 

have consumed 132.3 billion gallons if energy intensities had remained fixed at base-year values.

Because the nation actually consumed 113.1 billion gallons, improvements to energy intensity 

“saved” 19.2 billion gallons. 

SUMMARY OF DECOMPOSTION 4941

As expected, given the results of the Decomposition 4942, dropping vintage categories 

(denoted as Decomposition 4941 shown in Figure 27) from the decomposition had little impact on

partitioning out effects, meaning the proportion of vehicles (defined by vintage) in the end year 

(2001) is markedly similar to the base year (1988). In contrast, the Energy Intensity Effect still

played a significant part in reducing the nation’s energy use between 1988 and 2001. The 

improvement in energy intensity, all else being equal, would have resulted in an energy savings 

of 19.3 billion gallons, meaning the nation would have consumed 132.4 billion gallons if energy

intensities had remained fixed at 1988 levels. Comparing effects between Decompostions 4942

and 4941 on a one-to-one basis yields: 

• Housing Effect having no measurable difference, 

• Lifecycle Effect having no measurable difference, 

• Ownership Effect having no measurable difference, 

• Vehicle Type Effect having no measurable difference,

• Vehicle Use Effect having a 0.02 percent per year difference, 

 37 Wellner, A.S., Is 'Increasing Mobility' a Threat to U.S. Elder Care?, accessed online at www.prb.org on August 10, 

2005; Douglas A. Wolf and Charles F. Longino, Jr., Our ‘Increasingly Mobile Society’? The Curious Persistence of a 

False Belief, The Gerontologist 45, no. 1 (2005): 5-11. 

38 ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS
ENERGY OVERVIEW

• Energy Intensity Effect having no measurable difference, and 

• Interactions balance out numerically with the Vehicle Use Effect, a negative -0.02 

percent difference. 

Figure 27. Decomposition 4941 of Energy Needs, 1988 and 2001

2.46

1.52

-0.01

0.49 0.42

1.21

-1.20

0.04

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Annual Percent Growth

Source: Calculated by Energy Information Administration. 

Figure 28. Energy Savings from Energy Intensity, 2001

113.1

19.3

0

20

40

60

80

100

120

140

Use based on energy intensity at 1988, all else

fixed at 2001

G

E

G (billion)

Source: Calculated by Energy Information Administration. 

Decomposition 4941

2.46 PERCENT PER YEAR

OVERALL ENERGY GROWTH

1.52 PERCENT PER YEAR 

HOUSING EFFECT

-0.01 PERCENT PER YEAR 

LIFECYCLE EFFECT

0.49 PERCENT PER YEAR 

OWNERSHIP EFFECT

0.42 PERCENT PER YEAR 

VEHICLE TYPE EFFECT

-- PERCENT PER YEAR 

VINTAGE EFFECT

1.21 PERCENT PER YEAR 

VEHICLE USE EFFECT

-1.20 PERCENT PER YEAR 

ENERGY INTENSITY EFFECT

0.04 PERCENT PER YEAR 

INTERACTIONS

Concluded Energy Savings 

based on the Intensity Effect

19.3 million gasolineequivalent gallons (GEG)

Decomposing survey-to-survey energy use is yet another approach. While a longer term view 

on changes in energy use provides insights into energy “savings” from a slowly changing vehicle

stock, it precludes shorter term views. Additional insights are obtained by decomposing energy 

use using Equation 4 for shorter time periods: 1988-1991, 1991-1994, and 1994-2001 (see 

Figures 29 and 30). 

ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS 39
ENERGY OVERVIEW

Figure 29. Decomposition 4941 of Energy Use, 1988-1991, 1991-1994, and 1994-2001 0.16 3.03 3.22 1.36 -0.01 2.25 -0.18 0.62 -0.24 -0.3

7

0.72

0.78

0.35

0.36

0.48

1.31

2.61

0.65

-2.09

-1.26

-0.78

-0.22

0.00

0.0

7

-4

-3

-2

-1

0

1

2

3

4

1988-1991 1991-1994 1994-2001

Annual Percent 

Growth

Grouping effects from Decomposition 4941 by time period provides a much cleaner 

comparison of the magnitude of the trends occurring between 1988 and 2001 (see Figure 30). 

Figure 30. Decomposition 4941 of Energy Use by Effect, 1988-1991, 1991-1994, and 1994-2001 0.16 1.36 -0.18 -0.37 0.351.31 -2.09 -0.22 3.03 -0.010.62 0.72 0.36 2.61 -1.26 0.00 3.22 2.25 -0.24 0.78 0.48 0.65 -0.78 0.07

-4

-3

-2

-1

0

1

2

3

4

Annual P

ercent Growth

1988-1991 1991-1994 1994-2001

Housing

Effect

Lifecycle

Effect

Ownership

Effect

Vehicle

Type

Effect

Vehicle

Use

Effect

Energy

Intensity

Effect

Interactions

Overall

Energy

Growth

Source: Calculated by Energy Information Administration. 

Growth in energy use is uneven over the three time periods: 1988-1991, 1991-1994, and

1994-2001. Even though energy use grew 2.46 percent per year between 1988 and 2001, it was 

much slower between 1988 and 1991 (0.16 percent per year) than in subsequent years, which

experienced much stronger growth, up over 3 percent per year between 1991 and 2001. 

40 ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS
ENERGY OVERVIEW

Clearly, not all years are the same. One artifact of intermittent end-use data collection is

jumps and drops in statistics due to the economic activity or national hardship events occurring 

during the survey years.38 For instance, it could be argued that the recession between July 1990 

and March 1991 resulted in a retreat of energy use in 1991; however, teasing out the effects on 

energy use shows that several factors offset energy use: the Energy Intensity Effect (-2.09 percent

per year) the Lifecycle Effect (-0.18 percent per year) and the Ownership Effect (-0.37 percent 

per year). Without these effects, growth in energy use would have been over 3 percent per year,

even with a recession, all else remaining constant. Given the expected impacts on economic

wealth and financial security during a recession, a negative contribution to energy use between 

1988 and 1991 from vehicle ownership is not surprising. 

Table 3. Comparing Component Effects, 1988-1991, 1991-1994, and 1994-2001 

1988 – 1991

0.16 PERCENT PER YEAR

OVERALL ENERGY GROWTH

1991-1994 

3.03 PERCENT PER YEAR

OVERALL ENERGY GROWTH

1994-2001 

3.22 PERCENT PER YEAR

OVERALL ENERGY GROWTH

1.36 PERCENT PER YEAR 

HOUSING EFFECT

-0.18 PERCENT PER YEAR 

LIFECYCLE EFFECT

-0.37 PERCENT PER YEAR 

OWNERSHIP EFFECT

0.35 PERCENT PER YEAR 

VEHICLE TYPE EFFECT

-- PERCENT PER YEAR 

VINTAGE EFFECT

1.31 PERCENT PER YEAR 

VEHICLE USE EFFECT

-2.09 PERCENT PER YEAR 

ENERGY INTENSITY EFFECT

-0.22 PERCENT PER YEAR 

INTERACTIONS

-0.01 PERCENT PER YEAR 

HOUSING EFFECT

0.62 PERCENT PER YEAR 

LIFECYCLE EFFECT

0.72 PERCENT PER YEAR 

OWNERSHIP EFFECT

0.36 PERCENT PER YEAR 

VEHICLE TYPE EFFECT

-- PERCENT PER YEAR 

VINTAGE EFFECT

2.61 PERCENT PER YEAR 

VEHICLE USE EFFECT

-1.26 PERCENT PER YEAR 

ENERGY INTENSITY EFFECT

0.00 PERCENT PER YEAR 

INTERACTIONS

2.25 PERCENT PER YEAR 

HOUSING EFFECT

-0.24 PERCENT PER YEAR 

LIFECYCLE EFFECT

0.78 PERCENT PER YEAR 

OWNERSHIP EFFECT

0.48 PERCENT PER YEAR 

VEHICLE TYPE EFFECT

-- PERCENT PER YEAR 

VINTAGE EFFECT

0.65 PERCENT PER YEAR 

VEHICLE USE EFFECT

-0.78 PERCENT PER YEAR 

ENERGY INTENSITY EFFECT

0.07 PERCENT PER YEAR 

INTERACTIONS

 38 The 2001 NHTS was conducted over the 14-month period from March 2001 to May 2002. Unfortunately, that timing

turned out to be problematic due to the September 11, 2001 terrorist attacks on the World Trade Center in New York 

and the Pentagon in Washington, DC. These attacks disrupted transport services for months, especially curtailing longdistance travel. It is not certain what impacts the attacks had on urban travel, but it seems likely that both the amount of

travel and modal choice were affected. That may have distorted the survey results to some unknown extent. 

Information courtesy of John Pucher and John L. Renne, Transportation Quarterly, Vol. 57, No. 3, 2003. 

ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS 41
ENERGY OVERVIEW

ENERGY SAVINGS 

Based on the Intensity Effects, the nation has “saved” several billions of gallons of fuel from 

its deployment of less fuel intensive vehicles. That effect, however, has been offset in the United

States., as newer vehicles sought by consumers have become heavier, more powerful, and faster, 

while only moderately less fuel intensive. 

Figure 31. Concluded Energy

Savings, 1991 (Billion GEG)

82.8

5.4

70

80

90

100

110

120

Use based on

energy intensity at

1988, all else fixed

at 1991

Figure 32. Concluded Energy

Savings, 1994 (Billion GEG)

90.6

3.5

70

80

90

100

110

120

Use based on

energy intensity at

1991, all else fixed

at 1994

Figure 33. Concluded Energy

Savings, 2001 (Billion GEG)

6.4

113.1

70

80

90

100

110

120

Used based on

energy intensity at

1994, all else fixed

at 2001

TIME DURATION FOR INTENSITY 

EFFECT: 3 YEARS; FROM 1988 TO 

1991

TIME DURATION FOR INTENSITY 

EFFECT: 3 YEARS; FROM 1991 TO 

1994

TIME DURATION FOR INTENSITY 

EFFECT: 7 YEARS; FROM 1994 TO 

2001

Figures 31, 32, and 33 track the concluded energy savings by the nation’s vehicle stock due 

to lower energy intensities (i.e., improved energy performance). Over those times, energy was

saved because automakers had produced vehicles with greater energy performance. The savings, 

however, are not equally dispersed. In terms of volumes, the nation “saved” the greatest amount 

of fuel between 1994 and 2001 because of improved energy performance; yet, those 

improvements took 7 years, whereas the period between 1988 and 1991, in which vehicles also

achieved significant savings, improved such that 5.4 billion gallons was saved in only 3 years.

Based on those savings, the nation experienced a diminished efficacy of energy performance, 

with superior achievements occurring prior to 1991. Indeed, the energy savings registered with

1991 energy intensities (see Figure 32) further illustrates the downward trend in savings due to

energy performance of vehicles, with much less than the early period’s saved amount (3.5 billion 

versus 5.4 billion), over the same time duration: 3 years. 

COMPARING EFFECTS OVER TIME AND INTO THE FUTURE

Trends in the use of energy have been uneven for transport, as evidenced by the comparison 

of effects over time. Given the economic growth of the United States, as measured by GDP and 

real personal disposable income, the surge in energy use for transport is not particularly difficult 

to imagine – increased travel, increased ownership of vehicles that are heavier and more powerful

than their predecessors, and shifts in vehicle stock toward SUVs would seemly point to increased

42 ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS
ENERGY OVERVIEW

energy use. But, some effects – even offsetting ones – have shown some variations which could

point the way toward better managing future energy use: 

• The number of households with vehicles continues to increase, exhibiting an upward 

pressure on transport’s energy use, as measured by the Housing Effect. This effect is

expected to continue, depending on the population growth and life expectancy of the 

nation. 

• As the nation becomes populated with increasing number of elderly, the composition 

of households may prove to be a significant offset to energy use, as the

decomposition of Lifecycle Effect between 1994 and 2001 does impart some 

evidence that an aging population might continue to play an offsetting role. 

• As economic growth spreads among households, increasing the amount of real

disposable income, the number of vehicles per household (Ownership Effect) should

continue to move energy use higher, though some saturation point in vehicle stock is 

inevitable, effectively leveling this effect. 

• Gains in the use of energy for transport have mimicked consumers’ desire for heavier

and more powerful vehicles, as the Vehicle Type Effect revealed a consistent

pressure on energy use. Based on 2001 to 2004 new vehicle purchases, it is highly

likely this effect will continue in the nearer term, though recent trends in fuel prices 

could eventually dampen this effect. 

• In an environment in which Americans have increasingly moved to the exurbs, 

vehicle use continues to rise with people simply driving longer distances, though the

dip assessed in the 1994 to 2001 time period could be tied to the lingering effects

from the events occurring in September 2001. As the willingness of Americans to 

walk, share a commute, or take advantage of other forms of higher load sharing 

vehicles (e.g., buses) changes, this trend may fluctuate. 

• The nation’s growth in energy use was reduced 2.09 percent per year, 1.26 percent 

per year, and 0.78 percent per year for the time periods 1988-1991, 1991-1994, and

1994-2001, respectively. Lowering energy intensity has proven to be one of the 

largest, and most consistent, effects working to reduce the energy used by the nation 

for transport, though the greatest strives toward lowering energy intensity occurred 

before 1991. Post-1991 intensity improvements slowed dramatically. As new

vehicles enter the vehicle stock, they will most likely dictate the future impact on 

energy use. Based on sales-weighted fuel mileage estimated by the EPA, it is highly 

likely that impact on lessening energy use will further erode, as the fuel mileage is 

relatively unchanging or decreasing. 

This report has touched on only a few of the possible structure-energy, activity-energy, and 

intensity-energy links possible. Indeed, other reports and economic research have included

vehicle occupancy as another effect, determining whether vehicles are transporting more or less

people in their everyday use. As evidenced by the growth of GDP and transport use, economic 

growth is tied to the consumer’s ability to acquire goods and services; doing so in a sustainable 

manner – whether fuel prices are rising to record levels or not – is a worthwhile goal for the 

strategic use of energy by the nation’s 296 million final consumers.

ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS 43
ENERGY OVERVIEW

DATA FOR DECOMPOSITION 4941 

Table 4. Number of Households with Vehicles by Household Composition (Lifecycle), Selected 

Survey Years 

Survey Year

1988 1991 1994 2001

Number 

of HH 

(million) Share

Number 

of HH 

(million) Share

Number 

of HH 

(million) Share

Number 

of HH 

(million) Share

Total................................ 81.3 100.0 84.6 100.0 84.6 100.0 98.9 100.0 

 With Children 

Eldest Child < 7.......... 9.5 11.7 10.6 12.5 9.2 10.9 10.2 10.3 

Eldest Child 7 to 15.... 14.7 18.1 16.7 19.8 16.4 19.4 19.8 20.0 

Eldest Child 16 or 17 . 5.7 7.0 5.7 6.8 6.4 7.6 7.1 7.2 

 Without Children 

Two Adults, < 35 ........ 8.1 9.9 7.4 8.8 7.2 8.5 6.5 6.6 

Two Adults, 35 to 59 .. 12.8 15.8 12.5 14.7 15 17.7 17.3 17.5 

Two Adults, 60 plus ... 13.5 16.6 13.1 15.4 13.6 16.1 15.4 15.6 

One Adult ,< 35 .......... 5.0 6.1 4.2 4.9 3.4 4.0 3.3 3.4 

One Adult, 35 to 59 .... 5.3 6.5 6.5 7.7 6.6 7.8 9.0 9.1 

One Adult, 60 plus ..... 6.7 8.2 8.0 9.4 7.0 8.2 10.0 10.2 

Table 5. Number of Vehicles and Vehicle Ownership by Household Composition (Lifecycle), Selected 

Survey Years 

Survey Year

1988 1991 1994 2001

Number 

of 

Vehicles

(million)

Vehicles

per HH

Number 

of 

Vehicles

(million)

Vehicles

per HH

Number 

of 

Vehicles

(million)

Vehicles

per HH

Number 

of 

Vehicles

(million)

Vehicles

per HH

Total................................ 147.5 1.8 151.2 1.8 156.8 1.9 191.0 1.9 

 With Children 

Eldest Child < 7.......... 17.3 1.8 19.0 1.8 17.1 1.9 20.0 2.0 

Eldest Child 7 to 15.... 28.7 1.9 32.3 1.9 32.3 2.0 41.5 2.1 

Eldest Child 16 or 17 . 13.8 2.4 13.8 2.4 15.2 2.4 18.2 2.6 

 Without Children 

Two Adults, < 35 ........ 14.3 1.8 13.2 1.8 13.8 1.9 13.4 2.1 

Two Adults, 35 to 59 .. 29.4 2.3 27.8 2.2 33.9 2.3 41.0 2.4 

Two Adults, 60 plus ... 24.2 1.8 23.1 1.8 24.9 1.8 30.3 2.0 

One Adult ,< 35 .......... 5.7 1.1 5.0 1.2 4.1 1.2 3.7 1.1 

One Adult, 35 to 59 .... 7.1 1.3 7.6 1.2 7.6 1.2 11.5 1.3 

One Adult, 60 plus ..... 7.0 1.0 9.6 1.2 7.9 1.1 11.4 1.1 

44 ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS
ENERGY OVERVIEW

Table 6. Shares of Vehicles by Type and Household Composition (Lifecycle), Selected Survey Years 

Vehicle Shares

1988 1991 1994 2001

Households with Children, Eldest < 7 ........................................... 100.0 100.0 100.0 100.0 

 Passenger Cars........................................................................ 73.6 70.8 65.4 55.5 

 Vans ......................................................................................... 5.4 8.3 8.9 10.8 

 SUV.......................................................................................... 3.4 6.2 8.6 16.0 

 Pickups..................................................................................... 17.7 14.6 17.1 17.8 

Households with Children, Eldest 7 to 15 ..................................... 100.0 100.0 100.0 100.0 

 Passenger Cars........................................................................ 70.1 63.8 58.6 49.7 

 Vans ......................................................................................... 7.7 10.4 14.8 16.1 

 SUV.......................................................................................... 4.0 6.3 7.6 15.4 

 Pickups..................................................................................... 18.3 19.5 18.9 18.8 

Households with Children, Eldest 16 or 17................................... 100.0 100.0 100.0 100.0 

 Passenger Cars........................................................................ 73.4 66.1 64.2 55.0 

 Vans ......................................................................................... 6.1 8.4 9.9 13.0 

 SUV.......................................................................................... 3.5 4.4 5.7 13.3 

 Pickups..................................................................................... 16.9 21.1 20.2 18.7 

Households without Children, Two Adults, < 35.......................... 100.0 100.0 100.0 100.0 

 Passenger Cars........................................................................ 75.4 77.4 74.2 67.7 

 Vans ......................................................................................... 2.3 1.5 1.9 2.7 

 SUV.......................................................................................... 4.0 5.5 8.5 13.3 

 Pickups..................................................................................... 18.3 15.6 15.3 16.3 

Households without Children, Two Adults, 35 to 59.................... 100.0 100.0 100.0 100.0 

 Passenger Cars........................................................................ 71.1 69.3 66.7 56.7 

 Vans ......................................................................................... 4.2 4.4 4.1 6.9 

 SUV.......................................................................................... 3.6 5.1 6.4 12.5 

 Pickups..................................................................................... 21.1 21.3 22.8 23.9 

Households without Children, Two Adults, 60 plus..................... 100.0 100.0 100.0 100.0 

 Passenger Cars........................................................................ 75.8 75.2 72.6 63.2 

 Vans ......................................................................................... 3.6 4.5 5.6 9.1 

 SUV.......................................................................................... 1.7 2.5 3.1 6.9 

 Pickups..................................................................................... 18.9 17.7 18.7 20.8 

Households without Children, One Adult, < 35............................ 100.0 100.0 100.0 100.0 

 Passenger Cars........................................................................ 80.3 79 73.6 68.8 

 Vans ......................................................................................... 2.9 1.6 2.5 1.7 

 SUV.......................................................................................... 4.5 8.1 6.3 12.9 

 Pickups..................................................................................... 12.3 11.3 17.6 16.6 

Households without Children, One Adult, 35 to 59...................... 100.0 100.0 100.0 100.0 

 Passenger Cars........................................................................ 77.5 78.2 74.2 63.4 

 Vans ......................................................................................... 4.2 4.6 6.0 5.6 

 SUV.......................................................................................... 1.7 2.7 4.3 11.4 

 Pickups..................................................................................... 16.6 14.5 15.5 19.6 

Households without Children, One Adult, 60 plus....................... 100.0 100.0 100.0 100.0 

 Passenger Cars........................................................................ 89.0 88.0 88.7 82.2 

 Vans ......................................................................................... 0.1 0.8 0.4 4.3 

 SUV.......................................................................................... 1.8 1.3 0.7 3.8 

 Pickups..................................................................................... 9.0 9.8 10.2 9.7 

All Households................................................................................. 100.0 100.0 100.0 100.0 

 Passenger Cars........................................................................ 74.1 71.6 67.9 58.8 

 Vans ......................................................................................... 4.7 6.0 7.3 9.6 

 SUV.......................................................................................... 3.2 4.8 6.1 12.2 

 Pickups..................................................................................... 18.0 17.6 18.7 19.4 

ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS 45
ENERGY OVERVIEW

Table 7. Vehicle-Miles Traveled per Vehicle by Type and Household Composition (Lifecycle),

Selected Survey Years 

Vehicle-Miles Traveled per Vehicle 

(thousand)

1988 1991 1994 2001

Households with Children, Eldest < 7 ............................................ 11.3 11.2 12.1 13.7 

 Passenger Cars......................................................................... 11.5 11.2 12.0 12.9 

 Vans.......................................................................................... 11.5 10.8 12.2 16.4 

 SUV........................................................................................... 13.5 12.5 12.7 14.2 

 Pickups ..................................................................................... 9.9 11.0 12.0 14.1 

Households with Children, Eldest 7 to 15 ...................................... 10.9 11.7 12.3 13.5 

 Passenger Cars......................................................................... 11.1 11.9 12.1 13.3 

 Vans.......................................................................................... 11.8 13.0 13.9 13.9 

 SUV........................................................................................... 12.3 11.6 13.0 14.5 

 Pickups ..................................................................................... 9.6 10.6 11.4 12.7 

Households with Children, Eldest 16 or 17.................................... 11.9 11.7 12.5 13.4 

 Passenger Cars......................................................................... 12.3 11.7 12.8 12.8 

 Vans.......................................................................................... 13.2 10.6 13.6 14.2 

 SUV........................................................................................... 11.9 16.9 11.8 14.9 

 Pickups ..................................................................................... 9.4 11.3 11.5 13.3 

Households without Children, Two Adults, < 35........................... 11.4 11.9 12.7 13.7 

 Passenger Cars......................................................................... 11.2 12.1 12.5 13.6 

 Vans.......................................................................................... 9.7 14.7 15.6 15.6 

 SUV........................................................................................... 14.3 9.4 13.1 13.8 

 Pickups ..................................................................................... 11.9 11.4 12.6 13.9 

Households without Children, Two Adults, 35 to 59..................... 10.2 10.7 11.6 11.8 

 Passenger Cars......................................................................... 10.3 10.9 11.5 11.5 

 Vans.......................................................................................... 9.2 10.7 12.3 12.3 

 SUV........................................................................................... 10.5 11.5 12.6 13.1 

 Pickups ..................................................................................... 10.2 10.0 11.5 11.8 

Households without Children, Two Adults, 60 plus...................... 7.9 8.5 9.3 9.5 

 Passenger Cars......................................................................... 8.2 8.8 9.3 9.3 

 Vans.......................................................................................... 8.4 10.8 10.4 10.4 

 SUV........................................................................................... 8.4 8.7 12.7 11.0 

 Pickups ..................................................................................... 6.5 6.8 8.5 9.1 

Households without Children, One Adult, < 35............................. 12.1 11.9 13.0 13.2 

 Passenger Cars......................................................................... 12.2 12.1 13.2 12.5 

 Vans.......................................................................................... 9.8 12.5 12.0 14.3 

 SUV........................................................................................... 13.7 10.5 15.3 14.6 

 Pickups ..................................................................................... 11.1 11.9 11.5 15.0 

Households without Children, One Adult, 35 to 59....................... 9.3 10.7 11.2 10.9 

 Passenger Cars......................................................................... 9.8 10.9 11.2 10.3 

 Vans.......................................................................................... 7.3 8.3 10.5 10.9 

 SUV........................................................................................... 10.1 14.8 10.3 12.9 

 Pickups ..................................................................................... 7.4 9.4 12.0 11.3 

Households without Children, One Adult, 60 plus........................ 6.9 6.1 7.6 7.1 

 Passenger Cars......................................................................... 6.7 6.1 7.6 6.8 

 Vans.......................................................................................... 22.1 7.9 6.2 8.3 

 SUV........................................................................................... 10.1 4.9 7.2 10.1 

 Pickups ..................................................................................... 7.5 5.3 7.5 8.0 

46 ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS
ENERGY OVERVIEW

Table 8. Gasoline-Equivalent Gallons per 1000 Miles by Type and Household Composition

(Lifecycle), Selected Survey Years 

Gasoline-Equivalent Gallons per 1000 Mile

1988 1991 1994 2001

Households with Children, Eldest < 7 ........................................... 52.3 49.9 50.1 48.5 

 Passenger Cars........................................................................ 48.4 45.1 44.4 41.4 

 Vans ......................................................................................... 66.0 60.7 54.8 50.9 

 SUV.......................................................................................... 60.2 61.3 63.9 58.3 

 Pickups..................................................................................... 63.8 61.9 62.0 58.1 

Households with Children, Eldest 7 to 15 ..................................... 55.8 52.2 51.3 49.6 

 Passenger Cars........................................................................ 51.5 47.2 45.6 41.8 

 Vans ......................................................................................... 64.0 56.4 53.9 51.8 

 SUV.......................................................................................... 66.3 62.7 62.2 59.7 

 Pickups..................................................................................... 67.9 64.1 62.8 59.9 

Households with Children, Eldest 16 or 17................................... 52.7 52.4 50.2 49.1 

 Passenger Cars........................................................................ 49.1 46.5 45.3 42.2 

 Vans ......................................................................................... 63.8 62.2 58.3 52.3 

 SUV.......................................................................................... 64.6 61.9 59.2 59.1 

 Pickups..................................................................................... 64.7 64.5 60.4 58.2 

Households without Children, Two Adults, < 35.......................... 50.7 47.4 46.2 46.1 

 Passenger Cars........................................................................ 47.3 44.1 42.0 40.7 

 Vans ......................................................................................... 76.5 55.3 53.2 52.6 

 SUV.......................................................................................... 58.7 61.2 59.9 58.4 

 Pickups..................................................................................... 59.1 59.3 57.3 57.0 

Households without Children, Two Adults, 35 to 59.................... 55.4 51.9 51.3 50.1 

 Passenger Cars........................................................................ 50.9 47.6 45.5 43.3 

 Vans ......................................................................................... 70.3 62.8 62.3 53.3 

 SUV.......................................................................................... 67.6 56.6 58.6 58.1 

 Pickups..................................................................................... 66.2 63.2 63.9 60.3 

Households without Children, Two Adults, 60 plus..................... 58.6 54.6 53.2 52.1 

 Passenger Cars........................................................................ 55.6 50.8 49.6 45.7 

 Vans ......................................................................................... 73.7 58.9 58.5 52.8 

 SUV.......................................................................................... 65.5 68.4 64.5 59.8 

 Pickups..................................................................................... 69.7 71.3 63.7 68.4 

Households without Children, One Adult, < 35............................ 49.2 48.3 46.2 46.9 

 Passenger Cars........................................................................ 46.1 43.7 41.8 40.9 

 Vans ......................................................................................... 58.3 69.3 71.9 54.7 

 SUV.......................................................................................... 66.1 72.0 57.7 56.5 

 Pickups..................................................................................... 61.7 62.7 58.0 59.7 

Households without Children, One Adult, 35 to 59...................... 55.2 51.5 48.8 48.5 

 Passenger Cars........................................................................ 51.9 48.0 44.5 42.7 

 Vans ......................................................................................... 78.9 68.5 66.6 54.7 

 SUV.......................................................................................... 91.1 56.2 68.5 56.4 

 Pickups..................................................................................... 65.4 67.3 57.3 58.9 

Households without Children, One Adult, 60 plus....................... 60.0 57.2 50.7 49.3 

 Passenger Cars........................................................................ 56.7 55.1 49.5 46.6 

 Vans ......................................................................................... 51.6 64.9 55.2 53.6 

 SUV.......................................................................................... 60.6 81.4 63.8 57.2 

 Pickups..................................................................................... 88.6 75.0 60.8 63.6 

ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS 47
ENERGY OVERVIEW

Table 9. Number of Sampled Vehicles by Type and Household Composition (Lifecycle), Selected

Survey Years 

Number of Sampled Vehicles

1988 1991 1994 2001

Households with Children, Eldest < 7 ............................................ 796 802 629 3,852 

 Passenger Cars......................................................................... 578 557 414 1,995 

 Vans.......................................................................................... 45 60 55 451 

 SUV........................................................................................... 27 48 54 644 

 Pickups ..................................................................................... 146 137 106 762 

Households with Children, Eldest 7 to 15 ...................................... 1,265 1,350 1,168 8,446 

 Passenger Cars......................................................................... 870 864 683 3,933 

 Vans.......................................................................................... 97 134 168 1,385 

 SUV........................................................................................... 55 85 87 1,367 

 Pickups ..................................................................................... 243 267 230 1,761 

Households with Children, Eldest 16 or 17.................................... 639 582 547 3,900 

 Passenger Cars......................................................................... 474 385 356 2,090 

 Vans.......................................................................................... 36 44 48 495 

 SUV........................................................................................... 22 23 32 548 

 Pickups ..................................................................................... 107 130 111 767 

Households without Children, Two Adults, < 35........................... 655 529 505 2,418 

 Passenger Cars......................................................................... 494 392 378 1,543 

 Vans.......................................................................................... 14 9 9 74 

 SUV........................................................................................... 24 34 37 359 

 Pickups ..................................................................................... 123 94 81 442 

Households without Children, Two Adults, 35 to 59..................... 1,265 1,183 1,219 10,124 

 Passenger Cars......................................................................... 903 829 812 5,595 

 Vans.......................................................................................... 53 50 53 703 

 SUV........................................................................................... 45 60 76 1,344 

 Pickups ..................................................................................... 264 244 278 2,482 

Households without Children, Two Adults, 60 plus...................... 924 914 851 8,068 

 Passenger Cars......................................................................... 700 675 619 4,950 

 Vans.......................................................................................... 36 43 49 719 

 SUV........................................................................................... 15 28 25 594 

 Pickups ..................................................................................... 173 168 158 1,805 

Households without Children, One Adult, < 35............................. 187 198 136 668 

 Passenger Cars......................................................................... 148 142 103 433 

 Vans.......................................................................................... 4 5 3 15 

 SUV........................................................................................... 8 13 8 96 

 Pickups ..................................................................................... 27 38 22 124 

Households without Children, One Adult, 35 to 59....................... 220 251 236 2,527 

 Passenger Cars......................................................................... 177 193 178 1,531 

 Vans.......................................................................................... 8 10 15 141 

 SUV........................................................................................... 4 9 9 301 

 Pickups ..................................................................................... 31 39 34 554 

Households without Children, One Adult, < 60 plus..................... 218 275 262 2,733 

 Passenger Cars......................................................................... 194 240 231 2,192 

 Vans.......................................................................................... 1 5 1 123 

 SUV........................................................................................... 4 4 2 119 

 Pickups ..................................................................................... 19 26 28 299 

48 ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS
ENERGY OVERVIEW

REFERENCES

Boyd, G.A., Hanson D.A., and Sterner, T. “Decomposition of Changes in Energy Intensity: A

Comparison of the Divisia Index and Other Methods.” Energy Economics, 10 (1988): 309-312. 

Golob T. and Brownstone D. “The Impact of Residential Density on Vehicle Usage and Energy

Consumption.” University of California (Irvine), Institute of Transportation Studies, February 

2005. 

Schipper, L. and Ng, W. “Rapid Motorization in China: Environmental and Social Challenges.” 

World Resources Institute, EMBARQ, ADB-JBIC-World Bank East Asia and Pacific 

Infrastructure Flagship Study, October 18, 2004. 

Schipper, M. and Pinckney, D. “Supplementing The 2001 National Household Travel Survey 

With Energy-Related Data.” National Academy of Sciences, 83rd Transportation Research 

Board (TRB) Annual Meeting, National Data Requirements Programs Committee, January 14,

2004. 

Smil V. Energy at the Crossroads: Global Perspectives and Uncertainties. The MIT Press, 2003. 

Unander, F., Ting, M., Fulton, L., Justus, D., and Karbuz, S. 30 Years of Energy Use in IEA 

Countries: Oil Crises & Climate Change, International Energy Agency (Paris), 2004. 

ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS 49
ENERGY OVERVIEW

ABBREVIATIONS

ATS American Travel Survey

EIA Energy Information Administration 

EPA Environmental Protection Agency

BBL Barrel 

BEA Bureau of Economic Analysis 

BLS Bureau of Labor Statistics 

BTS Bureau of Transportation Statistics 

BTU British Thermal Unit 

CAFE Corporate Average Fuel Economy

CPI-U Consumer Price Index for Urban Areas 

DOE Department of Energy

DOT Department of Transportation 

FHWA Federal Highway Administration 

GEG Gasoline-Equivalent Gallon 

GHG Greenhouse Gases 

HP Horsepower 

IEA International Energy Agency

NHTS National Household Travel Survey

NHTSA National Highway Traffic Safety Administration 

NPTS Nationwide Personal Transportation Survey

MPG Miles per Gallon 

ORNL Oak Ridge National Laboratory

PMT Passenger-Miles Traveled 

POV Privately Owned Vehicle 

RTECS Residential Energy Transportation Survey

VMT Vehicle-Miles Traveled 

50 ENERGY INFORMATION ADMINISTRATION/HOUSEHOLD VEHICLES ENERGY USE: LATEST DATA & TRENDS