4. Vehicle Fuel Efficiency and Consumption

Fuel consumption is estimated from RTECS data on the vehicle stock (Chapter 2) and miles traveled (Chapter 3),

in combination with vehicle fuel efficiency ratings, adjusted to account for individual driving circumstances. The

first two sections of this chapter present estimates of household vehicle fuel efficiency and household fuel

consumption calculated from these fuel efficiency estimates. These sections also discuss variations in fuel efficiency

and consumption based on differences in household and vehicle characteristics. The third section presents EIA

estimates of the potential savings from replacing the oldest (and least fuel-efficient) household vehicles with new

(and more fuel-efficient) vehicles. The final section of this chapter focuses on households receiving (or eligible to

receive) supplemental income under government programs, in particular programs targeted at low-income households.

Vehicle Fuel Efficiency

The fuel efficiency of household vehicles averaged 19.3 miles per gallon (MPG) in 1991. This represents an increase

of 1 MPG (5.5 percent) since the 1988 RTECS, when household vehicles averaged 18.3 MPG. Fuel efficiency varies

by the age and type of vehicle. Newer cars are more fuel efficient than older cars, averaging 20.6 to 22.0 MPG for

model year 1983 or later compared with 12.2 MPG for model year 1973 or earlier. On average, passenger cars are

the most fuel efficient (21.1 MPG) and full-size vans the least efficient (13.7 MPG).

Calculation of Vehicle Fuel Efficiency

The vehicle fuel efficiencies presented in this report were calculated using the Environmental Protection Agency (EPA)

laboratory test results, adjusted for on-road driving. Information on vehicle characteristics, obtained from the Vehicle

Identification Number (VIN) and from the respondent, enhanced the matching of vehicles to the EPA certification files.

Earlier RTECS (prior to 1988) calculated fuel efficiencies using information recorded by respondents in vehicle fuelpurchase diaries.

A sequential adjustment procedure was used to adjust the EPA test data for each RTECS sample vehicle. First, the EPA

test data were adjusted to account for an MPG shortfall between the test data and the actual, on-road fuel efficiency for

a combination of both city and highway driving conditions. The resulting composite, or on-road MPG, is the "sticker"

MPG reported on new vehicles and published in the DOE/EPA Gas Mileage Guide. Next, the data were adjusted to

account for individual driving circumstances, in particular the effect of urban versus rural driving conditions and seasonal

effects. For each vehicle in the RTECS sample, the on-road MPG was adjusted based on the average number of miles

driven per day and whether the vehicle was driven in the North or the South. These adjustments provided specific in-use

MPG values for each vehicle in the RTECS sample. See Appendix B for additional details.

Two factors that also contribute to vehicle fuel efficiency--individual driving behavior and aging of vehicles--cannot be

determined because the RTECS fuel efficiency data were not measured from actual driving. This is important to keep

in mind when considering the information presented in this report, as driver behavior and vehicle aging have an additional

but unknown effect on the MPG of individual vehicles.

Energy Information Administration/Household Vehicles Energy Consumption 1991 27
Of the vehicle characteristics measured in the 1991 RTECS, the two most important ones affecting fuel efficiency

are the model year and the type of vehicle. The 1991 RTECS also identified differences in average vehicle fuel

efficiency based on household location, composition, and income.

Model Year

The fuel efficiency of household vehicles has increased significantly over the past 14 years. For 1979 and earlier

models, the average is 14.1 MPG or less. Since 1983, the average has risen above 20 MPG and has leveled out at

close to 22 MPG (Figure 13). The increase is largely due to a combination of the sharp increase in gasoline prices

in the 1970’s, which stimulated demand for more fuel-efficient vehicles, and the implementation of Corporate

Average Fuel Economy (CAFE)6 standards.

Figure 13. Average Fuel Efficiency of All Vehicles, by Model Year

6

Corporate Average Fuel Economy (CAFE) standards were established by the Energy Policy and Conservation Act of 1975. The standards

took effect in 1978.

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

0

5

10

15

20

25

30

35

Miles per Gallon

Pre-1974 1974-76 1977-79 1980-82 1983-85 1986-88 1989 1990 1991-92

Model Year

The average fuel efficiency of all vehicles, by model year, in the 1991 RTECS has risen from less than

13 miles per gallon for the oldest models to more than 21 miles per gallon for the newest models.

Consumption Survey.

Energy Information Administration/Household Vehicles Energy Consumption 1991 29
Even though the average fuel efficiency of new vehicles has stabilized over the past several years, the average for

the entire stock is still increasing as older, less fuel-efficient vehicles are replaced by newer vehicles that are more

fuel efficient. Between 1988 and 1991,7 average fuel efficiency increased for all vehicles and for passenger cars

in particular (Figure 14). The fuel economy of the total stock is expected to improve further as older, less efficient

vehicles continue to be replaced; however, the rate of improvement will slow as the percentage of pre-1979 vehicles

being replaced declines. Eventually, the fuel efficiency of new vehicles will need to be improved further in order

to boost the average fuel economy.

Figure 14. Average Fuel Efficiency of All Vehicles, by Type of Vehicle

Source: Energy Information Administration, Office of Energy Markets and End Use, 1991 Residential Transportation Energy

Average Passenger car Minivan Sport-Utility Van Pickup Truck

0

5

10

15

20

25

30

35

Miles per Gallon

18.3

19.3 19.7

21.1

19.4 19.6

15.4

16.2

13.1

13.7

15.3

15.8

Type of Vehicle

Average fuel efficiency varied by type of vehicle. For 1991, passenger cars had the highest average, at

21.1 miles per gallon. Vans had the lowest average, at 13.7 miles per gallon. The average for all vehicles

increased from 18.3 miles per gallon in 1988, to 19.3 miles per gallon in 1991.

1988

1991

Consumption Survey.

7

Fuel-efficiency data from the 1983 and 1985 RTECS cannot be directly compared to the 1988 or 1991 RTECS because of the change in the

RTECS fuel-efficiency methodology.

30 Energy Information Administration/Household Vehicles Energy Consumption 1991
Type of Vehicle

Another factor affecting average fuel efficiency is the composition of the vehicle stock. There is a fairly large

variation in fuel efficiency between different vehicle types, which are subject to different CAFE standards.8 For

example, minivans, large vans, and pickup trucks are less fuel efficient and have lower CAFE standards than

passenger cars. These types of vehicles have increased in popularity in recent years, reducing the proportion of more

fuel-efficient passenger cars in the residential fleet--from about 75 percent of the new vehicle stock (1988-1989

models) in 1988 to only 66 percent of the new vehicle stock (1991-1992 models) in 1991. Because of the increasing

proportion of minivans, large vans, and pickup trucks, the new vehicle fleet is less fuel efficient on average than it

would have been if the mix of passenger cars and other vehicles had not changed.

Between 1988 and 1991, vehicles with three types of characteristics showed significant improvements in fuel

efficiencies: passenger cars (from 19.7 MPG in 1988 to 21.1 MPG in 1991), vehicles equipped with automatic

transmissions (from 17.1 MPG to 18.4 MPG), and vehicles with engines 4.5 liters or larger (from 11.8 MPG to 14.0

MPG). Differences between the 1988 and 1991 surveys for other vehicle characteristics are not statistically

significant.

Location of Household

As in the 1988 RTECS, vehicles in households located in the Northeast were, on average, more fuel efficient in 1991

than those in other regions (Figure 15). Vehicles in the Northeast averaged nearly 21 MPG while those in the

Midwest, South, and West averaged closer to 19 MPG. The apparent reason for this finding is that, on average,

vehicles in the Northeast were newer and more likely to be passenger cars--two of the key factors that contribute

to higher average fuel efficiency (Figures 13 and 14). Newer vehicles are defined as model years 1983 and later,

and older models as 1979 or earlier. In the Northeast, about 12 percent of the vehicles were older (compared with

24 to 30 percent in the other three regions) and about 77 percent were newer (compared with 58 to 65 percent in

the other regions). The Northeast also had a higher proportion of passenger cars in its vehicle mix (80 percent

compared with 67 to 71 percent in the other three regions).

On average, vehicles in the central city and suburbs were more fuel efficient than vehicles used in rural9 areas (close

to 20 MPG for central cities and suburbs compared with 18 MPG for nonmetropolitan areas). The two primary

factors contributing to the lower fuel efficiency in rural areas are the relatively older age of the vehicle and the

relatively smaller percentage of passenger cars in the vehicle stock. In rural areas, 31 percent of the vehicles were

older vehicles and 56 percent were newer vehicles. This compares with 20 percent older/70 percent newer in

suburban areas and 22 percent older/65 percent newer in central cities. In addition, only 60 percent of all vehicles

in rural areas were classified as passenger cars (the rest were primarily pickup trucks and sport-utility vehicles)

compared with 74 percent in suburban areas and 78 percent in central cities.

8

Since 1983, CAFE standards for new model passenger cars have been set in the 26.0 to 27.5 MPG range (27.5 for 1990 and newer models).

Standards for light trucks, which include mini-vans and sport-utility vehicles, have been in the 19.0 to 20.5 range since 1983 (20.2 MPG in 1991).

For a manufacturer to meet the passenger car or light-truck standard, the models in the fleet that fall below the standard must be offset by models

that exceed the standard, such that a sales-weighted fleet average MPG meets the CAFE standards.

9

When the term "rural" is used, it refers to all nonmetropolitan areas in the United States. These are areas that are not located in a

Metropolitan Statistical Area. (See the Glossary for definition.)

Energy Information Administration/Household Vehicles Energy Consumption 1991 31
Figure 15. Average Fuel Efficiency of All Vehicles, by Census Region

Source: Energy Information Administration, Office of Energy Markets and End Use, 1991 Residential Transportation Energy

Average Northeast Midwest South West

0

5

10

15

20

25

Miles per Gallon

18.3

19.3 19.6

20.9

18.2

19.0

18.0

19.2

18.0

18.9

Census Region

Average fuel efficiency was greatest in the Northeast Region. Vehicles were younger

and there was a higher percentage of passenger cars in that region.

1988

1991

Consumption Survey.

Composition of Household

No significant differences in fuel efficiency were found between households with children and households without

children. Vehicles in households with children averaged 19.4 MPG, compared with 19.3 MPG for vehicles in

households without children.

32 Energy Information Administration/Household Vehicles Energy Consumption 1991
In households without children, average fuel efficiencies varied based on the age of the oldest household member

(Figure 16). Vehicles in households in which the oldest adult was under 35 years old were more fuel efficient than

those with older drivers. This difference can be attributed to the fact that older drivers, on average, had older

vehicles which are, on average, less fuel efficient.

Figure 16. Average Fuel Efficiency of All Vehicles, by Household Composition

Source: Energy Information Administration, Office of Energy Markets and End Use, 1991 Residential Transportation Energy

Average of All Households

Average of Households With Children

Average of Households Without Children

Under 7 Years

7 to 15 Years

16 or 17 Years

Under 35 Years

35 to 59 Years

60 Years or More

Under 35 Years

35 to 59 Years

60 Years or More

0 5 10 15 20 25

19.3

19.4

19.3

20.0

19.2

19.1

20.7

19.4

17.5

21.1

19.3

18.3

Miles per Gallon

Age of Householder,

Households Without

Children, Two or

More Adults

Age of Householder,

Households Without

Children, One Adult

Age of Oldest Child,

Households With

Children

Households with and without children had similar average fuel efficiencies. Households without children

and householders 60 or more years old had the lowest average fuel efficiencies.

Consumption Survey.

Energy Information Administration/Household Vehicles Energy Consumption 1991 33
Family Income

Vehicles in households with higher incomes had higher average fuel efficiencies than those in households with lower

incomes (Figure 17). Households in the income categories starting at $35,000/year averaged at least 20 MPG, while

those in income groups below $35,000/year averaged 19 MPG or less. This could be explained by the consistent

increase in the percentage of newer models (1983 and later) with each higher income category. Partially offsetting

the effect of vehicle age is the distribution of vehicle type as a function of income. Households in income categories

below $20,000/year had a higher percentage of passenger cars than households in the next higher income categories

up to $75,000/year (75-83 percent versus 67-70 percent). For households in the highest income categories (over

$75,000/year), the percentage of passenger cars was similar to the lowest income categories (79 percent).

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

Source: Energy Information Administration, Office of Energy Markets and End Use, 1991 Residential Transportation Energy

Average

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 More

0 5 10 15 20 25 Miles per Gallon

19.3

18.4

17.7

18.2

18.6

17.9

19.0

20.3

20.1

20.3

Average fuel efficiency varied by family income. Households with higher incomes had greater

average fuel efficiencies than households with lower incomes.

Consumption Survey.

Vehicle Fuel Consumption

Household vehicles consumed a total of 82.8 billion gallons of fuel in 1991 (compared to 82.4 billion gallons in

34 Energy Information Administration/Household Vehicles Energy Consumption 1991
1988). This equates to 548 gallons per vehicle (559 gallons in 1988) and 979 gallons per household (1,014 gallons

in 1988). The 1991 RTECS identified differences in average household and vehicle fuel consumption based on

household characteristics (location and composition) and vehicle characteristics (type and model year).

Energy Information Administration/Household Vehicles Energy Consumption 1991 35
Location of Household

Calculation of Vehicle Fuel Consumption

Total vehicle fuel consumption is a function of fuel efficiency and the number of miles traveled. The 1991 RTECS calculated

annual vehicle fuel consumption by dividing the annual vehicle miles traveled (VMT) by the annual fuel efficiency. These fuel

efficiencies were derived based on EPA test data rather than on actual fuel purchases (see Calculation of Vehicle Fuel Efficiency).

Because the RTECS did not directly measure fuel consumption, this report does not consider the effects of driving behavior and

vehicle aging on energy consumption.

Average annual vehicle fuel consumption was lower in the Northeast than in any other Census region (Figures 18

and 19). Households in the Northeast consumed a total of 886 gallons per household, compared with an average

range of 978 to 1,008 gallons per household in the other three regions. Households in the Northeast also consumed

Figure 18. Average Annual Household Fuel Consumption, by Census Region

Average Northeast Midwest South West

0

200

400

600

800

1000

1200

Consumption per Household (gallons)

979

886

1008 1008

978

Census Region

The Northeast Region had the lowest average annual fuel consumption. Vehicles in that region

had the highest average fuel efficiency.

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

Consumption Survey.

less on average per vehicle than the South (523 gallons versus 566 gallons), but not significantly less than the other

two regions. The lower average consumption for the Northeast was largely due to the higher fuel efficiency of

vehicles in the region. Vehicle miles traveled (VMT), per household as well as per vehicle, were similar for all four

regions.

Figure 19. Average Annual Vehicle Fuel Consumption, by Census Region

Source: Energy Information Administration, Office of Energy Markets and End Use, 1991 Residential Transportation Energy

Average Northeast Midwest South West Census Region

0

100

200

300

400

500

600

700

Consumption per Vehicle (gallons)

548

523

554

566

532

The Northeast Region had lower average annual fuel consumption per vehicle. Vehicles in that

region had the highest average fuel efficiency.

Consumption Survey.

Households in rural areas used more fuel per household and per vehicle than central city households (34 percent

greater per household and 13 percent greater per vehicle) or suburban households (26 percent greater per household

and 9 percent greater per vehicle). These differences can be explained by the lower fuel efficiency in rural areas

(which accounted for greater average consumption) and the lower VMT per household in central city areas (which

Energy Information Administration/Household Vehicles Energy Consumption 1991 37
reduced average household and vehicle consumption).

38 Energy Information Administration/Household Vehicles Energy Consumption 1991
Composition of Household

Trends in average household fuel consumption parallel trends in VMT per household. The variation in consumption

among different household categories was largely controlled by VMT per household and less by other factors.

Households without children consumed more fuel in total than households with children (44.0 billion gallons

compared with 38.9 billion gallons). However, households with children consumed more fuel on average (1,176

gallons per year compared with 852 gallons in households without children--Figure 20). Those whose oldest child

was 16 or 17 years old consumed more fuel than any other group (1,468 gallons). Not surprisingly, households with

no children and only one adult consumed the least fuel (556 gallons per year). These observations are consistent

with the finding that lower VMT correlated with lower fuel consumption (see Chapter 3).

Figure 20. Average Annual Household Fuel Consumption, by Household Composition

Source: Energy Information Administration, Office of Energy Markets and End Use, 1991 Residential Transportation Energy

Average of All Households

Average of Households with Children

Average of Households Without Children

Under 7 Years

7 to 15 Years

16 or 17 Years

Under 35 Years

35 to 59 Years

60 Years or More

Under 35 Years

35 to 59 Years

60 Years or More

0 200 400 600 800 1000 1200 1400 1600

979

1176

852

1011

1180

1468

685

644

417

996

1240

822

Age of Householder,

Households Without 

Children, Two or 

More Adults

Age of Householder,

Households Without

Children, One Adult

Age of Oldest Child,

Households With 

Children

Households with children consumed more fuel per household than households without children. Those with children

16 or 17 years old consumed the most, and those with a single adult 60 years or older consumed the least.

Consumption per Household (gallons)

Consumption Survey.

Energy Information Administration/Household Vehicles Energy Consumption 1991 39
Average annual fuel consumption per vehicle did not vary much by household composition. All but one of the

household subcategory groups consumed in the range of 466-613 gallons/year, on average. Households with a single

adult 60 years or older and no children, however, consumed significantly less fuel per vehicle (347 gallons) primarily

because their VMT per vehicle was lower than for any other group.

Type of Vehicle

The 1991 RTECS data by type of vehicle reveal different patterns for total and average annual vehicle fuel

consumption (Figures 21 and 22). For example, passenger cars consumed the most fuel in total (54.5 billion gallons)

but the least fuel per vehicle (503 gallons). Total consumption for the different types of vehicles is the product of

average fuel efficiency and total VMT. For passenger cars, the high consumption was mainly the result of the high

total VMT, which is a function of the greater number of these vehicles.

Figure 21. Total Annual Vehicle Fuel Consumption, by Vehicle Type

Source: Energy Information Administration, Office of Energy Markets and End Use, 1991 Residential Transportation Energy

Total Passenger car Minivan Sport-Utility Van Pickup Truck

0

10

20

30

40

50

60

70

80

90

Total Consumption (billion gallons)

82.8

54.5

3.3

5.2

2.9

16.4

Type of Vehicle

Passenger cars consumed 65.8 percent and pickups 19.7 percent of total

household vehicle consumption. Total VMT was greatest for those two vehicle

types, with passenger cars 71.8 percent of the total and pickups 16.1 percent.

Consumption Survey.

40 Energy Information Administration/Household Vehicles Energy Consumption 1991
Energy Information Administration/Household Vehicles Energy Consumption 1991 41
Figure 22. Average Annual Vehicle Fuel Consumption, by Vehicle Type

Source: Energy Information Administration, Office of Energy Markets and End Use, 1991 Residential Transportation Energy

Total Passenger car Minivan Sport-Utility Van Pickup Truck

0

100

200

300

400

500

600

700

800

Consumption per Vehicle (gallons)

548

503

646

717

736

632

Type of Vehicle

Passenger cars used the fewest gallons per vehicle 

of all vehicle types. They had the highest average 

fuel efficiency of all vehicle types.

Consumption Survey.

One trend which may affect future consumption patterns is the increasing popularity of minivans, which increased

their market share from 1.5 percent of vehicles in 1988 to 3.4 percent in 1991. Minivans (which are classified as

light trucks for CAFE purposes) are less fuel efficient on average than passenger cars. The percentage of new model

passenger cars has already declined from 75 percent in the 1988 RTECS to 66 percent in 1991. If the recent trend

continues, minivans will increasingly replace passenger cars in the vehicle stock. This change in vehicle mix will

raise the overall average fuel consumption per vehicle above the comparable level if passenger cars had been

purchased instead of minivans.

Model Year

Based on the 1991 RTECS, consumption per vehicle increased from pre-1974 models through 1979 models, then

declined for the 1980-1982 model year category. The increase for the models of the 1970 decade reflects the higher

VMT per vehicle for those models and relatively little increase in fuel efficiency. The decreases for the 1980-1982

42 Energy Information Administration/Household Vehicles Energy Consumption 1991
models are due to major improvements in fuel efficiency (Figure 23). In the early 1980’s, there was no significant

change in VMT per vehicle. Since the 1982 model year, continuing increases in VMT per vehicle more than offset

fuel savings due to improvements in fuel efficiency, increasing consumption per vehicle.

Energy Information Administration/Household Vehicles Energy Consumption 1991 43
Figure 23. Average Annual Vehicle Fuel Consumption, by Vehicle Model Year

Source: Energy Information Administration, Office of Energy Markets and End Use, 1991 Residential Transportation Energy

Pre-1974 1974-76 1977-79 1980-82 1983-85 1986-88 1989 1990

0

100

200

300

400

500

600

700

800

Consumption per Vehicle (gallons)

Model Year

Consumption per vehicle is a function of VMT per vehicle and MPG. Consumption per vehicle was

greater for 1974-76 and 1977-79 model years because of lower MPG. Consumption for the latest model

years was greater because of greater VMT per vehicle.

1991-92

Consumption Survey.

Potential Fuel Savings from Replacing Old Vehicles

Using the RTECS data, it is possible to estimate energy savings that could occur if a portion of the existing vehicle

stock were replaced with more fuel-efficient vehicles10. However, it is difficult to accurately estimate these savings

because the new, replacement vehicles may be used differently. RTECS data indicate that newer vehicles are driven

more on average, and the acquisition of a newer vehicle may cause households with more than one vehicle to alter

the pattern of vehicle usage in ways that are difficult to characterize. Even though it is likely that the replacement

vehicles will be driven more than the older vehicles they replace, a particular household may acquire a newer vehicle

for a specific purpose that precludes it from becoming the household’s primary, or high VMT, vehicle.

10A similar analysis was performed for household appliances and equipment in "Potential Efficiency Gains and Energy Savings from Replacing

1990 Stock with 1990 New Appliance Units," Household Energy Consumption and Expenditures 1990, DOE/EIA-0321(90), pp. 30-35. That

analysis showed that significant savings are possible if older, less efficient household equipment is replaced with new energy-efficient equipment.

44 Energy Information Administration/Household Vehicles Energy Consumption 1991
Energy Information Administration/Household Vehicles Energy Consumption 1991 45
Given these difficulties, a simple, hypothetical example may better illustrate possible fuel savings. By starting with

the simplifying assumption that the replacement vehicle is driven the same number of miles as the older vehicle it

replaces, the required calculation can be made easily with the RTECS data.

First, assume all vehicles that are older than the 1980 model year are replaced with new (1991-92) models. By

targeting only pre-1980 vehicles for replacement, it is possible to estimate the impact of replacing the least efficient

model years in the stock with the most efficient. According to the RTECS, 35.1 million vehicles from the pre-1980

model year consumed a total of 19.1 billion gallons of fuel in 1991 (23 percent of all fuel consumed by household

vehicles). These older vehicles traveled a total of 253 billion miles (16 percent of total VMT in 1991), for an

average VMT per vehicle of 7,200 miles. Assuming the new model replacement vehicles also averaged 7,200 miles

each, and their average fuel efficiency was 21.8 MPG (the average of the new 1991 vehicles), the replacement

vehicles would use only 11.6 billion gallons of fuel--a fuel savings of 7.5 billion gallons. This is equivalent to 9.1

percent of the total 1991 fuel consumption.11

Even greater savings could be realized if the replacement vehicles were more fuel efficient than the average of new

1991 vehicles. For example, the fuel savings would increase to 10.7 billion gallons (13 percent of total fuel

consumption in 1991) if the replacement vehicles averaged 30 MPG; 12.8 billion gallons (15 percent) for 40 MPG;

and 14.0 billion gallons (17 percent) for 50 MPG.

Although these results are significant, the energy savings are not as impressive as those estimated in a similar

analysis for replacement of older household appliances. The potential energy savings from the replacement of old

household appliances are relatively larger because inefficient household appliances represent a relatively larger

proportion of the household appliance stock. Fuel savings due to retirement of "gas guzzlers" are relatively smaller

because a substantial number of these vehicles (i.e., pre-1980 vehicles) already have been taken off the road.

Fuel Consumption in Households Participating in Income

Supplement Programs

The 1991 RTECS included data on vehicle use, fuel consumption, and fuel expenditures for households that

participate in several income supplement programs (Table 6), ranging from Social Security and pension programs

to food stamps and Aid to Families with Dependent Children (AFDC). Households may qualify for more than one

program. With the exception of Social Security, pension programs, and unemployment benefits, these programs are

targeted at low-income households.

On average, households in income supplement programs traveled fewer miles, consumed less fuel, and spent less

money for motor fuels than the population of all households with vehicles. These findings were consistent with

observations, noted earlier, for households with older drivers (such as retired persons) and for lower income

households.

11The Office of Technology Assessment (OTA) estimated the impact of a program that would allow automobile companies to purchase and

retire pre-1975 cars for the purpose of removing inefficient, polluting vehicles from the road. In return, the companies would be awarded credits

toward meeting their CAFE standards. OTA estimated that 370-520 gallons per vehicle per year could be saved. The total savings would depend

upon the number of vehicles scrapped. The 1991 RTECS estimated that there are approximately 13.5 million pre-1975 vehicles in the stock.

If all were replaced, and the OTA estimate of savings per vehicle is used, between 5 and 7 billion gallons of fuel would be saved. Although OTA

used a different set of assumptions and a different methodology, the range of savings is very close to the fuel savings of 7.5 billion gallons

estimated here. U.S. Congress, Office of Technology Assessment, Retiring Old Cars: Programs To Save Gasoline and Reduce Emissions, OTA-E536, July 1992.

46 Energy Information Administration/Household Vehicles Energy Consumption 1991
Energy Information Administration/Household Vehicles Energy Consumption 1991 47
Table 6. U.S. per Household Vehicle Miles Traveled, Vehicle Fuel Consumption and Expenditures

for Income Supplement Programs, 1991

Income Supplement

Program

Number of

Households

with Vehicles

(million)

Average per Household

Number of

Vehicles

Vehicle Miles

Traveled

(thousand)

Consumption

(gallons)

Expenditures

(dollars)

Total U.S. ........ 84.6 1.8 18.9 979 1,161

Social Securitya .... 21.4 1.6 12.9 718 852

Pension Fundsb .... 15.3 1.7 14.1 756 898

Unemployment

Benefits . . . . . . . . . 2.7 1.9 21.1 1,087 1,292

Food Stamps . . . . . . 3.4 1.3 12.2 710 828

AFDC Incomec . . . . . 2.2 1.4 13.4 769 898

SSI Incomed . . . . . . 1.7 1.4 11.3 649 758

Other Aid ........ 1.5 1.4 11.2 644 753

a

Includes social security and railroad retirement pension income.

b

Pension income other than social security and railroad retirement.

c

AFDC--Aid to Families with Dependent Children.

d

Supplemental security income administered by the Social Security Administration.

Source: Energy Information Administration, Office of Energy Markets and End Use, 1991 Residential Transportation Energy

Consumption Survey.

The only exception is households that received unemployment benefits. These households had more vehicles,

traveled more miles, consumed more fuel, and spent more on motor fuels than the other groups that received income

supplements. Inclusion in this category required only that at least one household member received unemployment

benefits sometime during the year. These households were at or near national household averages for family income,

numbers of drivers and numbers of vehicles, i.e., they were more typical of the national average than the other

income supplement households.

The 1991 RTECS collected more detailed information from a small number of households that received, or were

eligible to receive, public assistance such as food stamps, AFDC, and LIHEAP12 (Table 7). Because the total

number of cases in the RTECS sample with these characteristics was small, the relative standard errors were fairly

large. As a result, some data in this table were withheld.

Low-income households receiving public assistance spent a larger proportion of their incomes to fuel their vehicles--

typically twice as much as higher income households. For example, Midwest households receiving food stamps spent

13.1 percent of their income on motor fuel, compared with only 5.4 percent for all households in the Midwest Census

region. Because of the large percentage of income spent on fuel, low-income households were affected relatively

more than other households by any change in the price of fuel.

Low-income households receiving public assistance also had a greater percentage of older vehicles than average

(Table 7). The average age of their vehicles was typically two or more years older than higher income households,

so they did not benefit as much from the greater fuel efficiency of newer vehicles. In addition, many of the older

vehicles required more expensive, higher grades of gasoline, which added to fuel expenditures.

12Low-Income Home Energy Assistance Program. Established by the Low-Income Home Energy Assistance Act of 1981, LIHEAP provides

Federal funds to States to assist eligible low-income households with heating and cooling bills.

48 Energy Information Administration/Household Vehicles Energy Consumption 1991
Within each vehicle vintage category, however, the vehicles belonging to low-income groups had similar to slightly

better fuel efficiency than the overall average for each category. The lower fuel efficiency of vehicles belonging

to low-income groups was therefore a reflection of the age of the vehicles, not the type of vehicle. Although lowincome groups on average had older vehicles, the vehicle type in itself was not less efficient than higher income

groups.

Table 7. Summary of Household and Vehicle Characteristics by Categories of Income

Assistance, 1991

Household or Vehicle

Characteristic

All Households

with Vehicles

Households Receiving or Eligible for Assistance

Food Stamps AFDC Income

Eligible for

LIHEAP

Received

LIHEAP

Number of Households with

Vehicles (million)

All Regions ............ 84.6 3.4 2.2 20.8 2.9

Northeast .............. 16.0 Q Q 3.0 Q

Midwest ............... 21.1 Q Q 4.9 0.9

South ................. 29.5 1.4 Q 8.5 0.7

West ................. 18.0 Q Q 4.3 0.7

Income Spent Income Spent onon Motor Motor Fuel Fuel

(percent of total income)

All Regions . . . . . . . . . . . . 5.4 12.6 13.4 11.3 11.7

Northeast . . . . . . . . . . . . . . 3.9 Q Q 8.2 13.2

Midwest . . . . . . . . . . . . . . . 5.4 13.1 12.8 11.2 10.7

South . . . . . . . . . . . . . . . . . 6.0 10.9 11.8 11.7 14.0

West . . . . . . . . . . . . . . . . . 5.5 12.5 13.4 12.7 9.6

Average Age Average Age of of Vehicles Vehicles

(years)

All Regions . . . . . . . . . . . . 7.7 11.8 11.3 9.9 11.6

Northeast . . . . . . . . . . . . . . 6.1 Q Q 6.8 8.9

Midwest . . . . . . . . . . . . . . . 7.7 Q 8.9 9.7 12.2

South . . . . . . . . . . . . . . . . . 7.7 10.7 11.5 9.9 10.9

West . . . . . . . . . . . . . . . . . 8.9 15.2 Q 11.7 13.1

Number of Number of Vehicles Vehicles byby

Vintage (million) Vintage

All Years .............. 151.2 4.3 3.0 29.8 3.8

1989 to 1992 ........... 28.5 Q Q 3.7 0.4

1983 to 1988 ........... 70.0 1.1 0.9 10.1 0.8

1977 to 1982 ........... 34.2 1.6 Q 10.1 1.5

1976 and Before ......... 18.5 1.2 Q 6.0 1.0

Average Fuel Average Fuel Efficiency Efficiency

(miles per gallon)

All Years .............. 19.3 17.2 17.4 17.9 17.1

1989 to 1992 ........... 21.7 Q Q 22.7 22.5

1983 to 1988 ........... 21.4 22.4 21.3 21.5 22.5

1977 to 1982 ........... 16.4 16.8 Q 16.2 16.0

1976 and Before ......... 12.4 12.3 Q 12.1 12.8

Q = Data withheld either because the Relative Standard Error (RSE) was greater than 50 percent or fewer than 10 households were

sampled.

Source: Energy Information Administration, Office of Energy Markets and End Use, 1991 Residential Transportation Energy

Consumption Survey.

Energy Information Administration/Household Vehicles Energy Consumption 1991 49