Chapter 2. Vehicle Characteristics
U.S.
households used a fleet of nearly 157 million vehicles in 1994.
Despite remarkable growth in the number of minivans and sport-utility
vehicles, passenger cars continued to predominate in the residential
vehicle fleet. This chapter looks at changes in the composition
of the residential fleet in 1994 compared with earlier years and
reviews the effect of technological changes on fuel efficiency (how
efficiently a vehicle engine processes motor fuel) and fuel economy
(how far a vehicle travels on a given amount of fuel). Using data
unique to the Residential Transportation Energy Consumption Survey,
it also explores the relationship between residential vehicle use
and family income.
Changes
in the Composition of the Residential Fleet
The
number of vehicles in U.S. households rose from 148 million in 1988
to 157 million in 1994, an increase of 9 million vehicles. During
the same period, the U.S. population grew by almost 15 million persons
to 260 million.(1) The average annual
growth rates of both residential vehicles and population equaled
1.0 percent. The number of licensed drivers grew(2)
at an average annual rate of 1.2 percent, and, in 1994, there were
1.1 licensed drivers per residential vehicle, slightly more than
in 1988.
Residential
vehicles continued to account for the majority of all U.S. vehicles.
Not surprisingly, the rate of increase in vehicles available for
use in households was approximately the same as the rate of increase
for the U.S. total vehicle stock (Figure 2.1).
Note:
U.S. total vehicles include motorcycles and buses, as well as other
nonresidential vehicles, which are excluded from the Residential
Transportation Energy Consumption Survey. Sources: U.S.
Total Vehicles: Energy Information Administration (EIA),
Annual Energy Review 1995, DOE/EIA-0384(95) (Washington,
DC, July 1996), Table 2.16. Residential Vehicles:
1983--EIA, Consumption Patterns of Household Vehicles 1983,
DOE/EIA-0464(83) (Washington, DC, January 1985), Table 11. 1985--EIA,
Consumption Patterns of Household Vehicles 1985, DOE/EIA-0464(85)
(Washington, DC, April 1987), Table 8. 1988--EIA, Household
Vehicles Energy Consumption 1988, DOE/EIA-0464(88) (Washington,
DC, February 1990), Table 6. 1991--EIA, Household Vehicles Energy
Consumption 1991, DOE/EIA-0464(91) (Washington, DC, December
1993), Table 8. 1994--Table 5.1 in this report.
A
Growing Number of Passenger Cars Were Replaced by Light Trucks
The
number of passenger cars in U.S. households was 106 million in 1994
(Figure 2.2). At a 68-percent share, passenger cars continued to
dominate the residential fleet, but not to the same extent as in
1988, when their share was 74 percent.
Note:
Totals may not equal sum of components due to independent rounding.
Sources: 1988--Energy Information Administration, Household
Vehicles Energy Consumption 1988, DOE/EIA-0464(88) (Washington,
DC, February 1990), Table 6. 1994--Table 5.1 in this report.
In
contrast, there was remarkable growth in the number of household
vehicles categorized as light trucks, particularly minivans. From
1988 through 1994, the number of light trucks in the residential
fleet increased by an estimated 12 million, which more than compensated
for the apparent decline in the number of passenger cars.
The
number of minivans grew dramatically. It rose from
2.2 million in 1988 to 8.1 million in 1994, an increase of 268 percent
(Figure 2.3). Minivans, introduced into the market in the mid-1980's,
accounted for nearly 1 in 20 residential vehicles in 1994.
Sources:
1988--Energy Information Administration, Household Vehicles
Energy Consumption 1988, DOE/EIA-0464(88) (Washington, DC,
February 1990), Table 6. 1994--Table 5.1 in this report.
Sport-utility
vehicles, termed "jeep-like" vehicles in the
1988 survey, also increased in number at a remarkable rate. From
1988 through 1994, they rose 98 percent to 9.5 million.
Pickup
trucks were the most prevalent of the light trucks on the
road. Almost 1 in 5 residential vehicles in 1994 was a pickup truck.
In 1994, the number of pickup trucks totaled 29 million.
The
only type of light truck estimated to have declined over the period
was the large van. The large van share of the residential
fleet fell from 3 percent in 1988 to 2 percent in 1994 when large
vans numbered 3.4 million.
Throughout
the 7-year period of 1988 through 1994, inflation-adjusted prices
of motor fuel (motor gasoline and diesel fuel) were well below the
peak prices of the early 1980's. For example, at its peak in 1981,
the adjusted price (in chained [1992] dollars(3) and including taxes) of unleaded regular motor
gasoline was $2.09 per gallon, whereas in 1994 the comparable price
was $1.06.(4)
When
motor fuel prices are relatively low, consumers have less incentive
for choosing vehicles with higher fuel economy ratings. And, in
fact, consumer preference for light trucks, which have significantly
lower fuel economy ratings than do passenger cars, was one factor
leading to the decline in the number of passenger cars. A second
factor contributing to the increase in light trucks' share of the
residential fleet was the continuing tendency of householders to
keep older light trucks in operation while retiring older passenger
cars. Those factors had their greatest effect in the West, where
light trucks make up a higher percentage of the residential vehicle
fleet than in other regions.
Consumer
Preference for Light Trucks Increased
Total
sales of new light trucks to all sectors rose during the 1980's
and 1990's (Figure 2.4). For model year 1995, 5.7 million light
trucks were sold, more than ever before and nearly three times the
number of sales for model year 1980. Although sales of new passenger
cars fluctuated and rose as high as 11 million for model year 1986,
for model year
Source:
Federal Highway Administration, Summary of Fuel Economy Performance
(Washington, DC, April 1996), p. 3.
1995
sales of 9.2 million were about the same as they had been for model
year 1980 (9.4 million). For model year 1995, therefore, light trucks
accounted for slightly more than one-third of total sales.
Sales
data disaggregated by sector are not available, but changes in the
composition of the residential fleet, as noted above, clearly reflect
householders' growing preference for light trucks. That preference
restrained the increase in the fuel economy of the residential fleet
as a whole (see Chapter 4).
Light
Trucks Were Kept in Operation Longer
Although
the number of old passenger cars in the residential fleet declined
rapidly from 1988 through 1994, old light trucks, particularly pickup
trucks and large vans, were taken out of service at a slower rate.
For example, the number of passenger cars of model year 1982 or
earlier fell from 57 million in 1988 to 20 million in 1994, meaning
that about two-thirds of those older passenger cars were retired
from the residential fleet over the 7-year period (Figure 2.5).
By comparison, the number of pre-1983 light trucks fell from 21
million to 11 million, meaning that only about one-half were retired.
Sources:
1988--Energy Information Administration (EIA), Household Vehicles
Energy Consumption 1988, DOE/EIA-0464(88) (Washington, DC,
February 1990), Table 9. 1991--EIA, Household Vehicles Energy
Consumption 1991, DOE/EIA-0464(91) (Washington, DC, December
1993), Table 11. 1994--Table 5.4 in this report.
The
tendency to retain old light trucks led to a difference in the average
age of light trucks and passenger cars. In the 1994 fleet, the average
age of passengers cars was 8.1 years. Light trucks as a group averaged
8.5 years, but there was wide variation in the average age of different
types of light trucks. For example, pickup trucks and large vans
were, on average, 9.9 years old, whereas sport-utility vehicles
averaged 6.6 years and minivans averaged 4.8 years.
Light
Trucks Were Most Prevalent in the West
In
1994, the western fleet had a high ratio of light trucks to passenger
cars. Light trucks made up 37 percent of the residential fleet in
the West, compared with 33 percent in the South, 30 percent in the
Midwest, and 26 percent in the Northeast (Figure 2.6).
Source: Table 5.16 in this report.
The
national tendency to keep old trucks in service longer than old
cars meant that in the West old residential vehicles as a whole
were taken out of service at a slower rate than in the other regions
of the country. For example, vehicles of model year 1988 or earlier
accounted for a 64-percent share of all of the residential vehicles
in the West. In the other regions of the country, the shares were
lower: 59 percent in the Midwest and 57 percent each in the South
and Northeast.
The
rural nature of much of the West may have contributed to the prevalence
of light trucks in the region. In general, rural areas had a higher
ratio of light trucks to passenger cars than did urban areas. Even
California, the most populous State in the West, had a ratio above
the national average. In California, 1 of every 3 residential vehicles
was a light truck. In contrast, in New York fewer than 1 in 4 was.
Residential Vehicles at
the Household Level
In 1994, the 156.8 million residential vehicles
were divided among the 84.9 million households that had at least
one vehicle, meaning that each of those households had an average
of about 1.8 vehicles. Despite the increase in the total number
of vehicles in the residential fleet from 1988 to 1994, the average
number of vehicles per household remained at 1.8 because the growth
in the number of households kept pace with the growth in the number
of vehicles. An additional 12.5 million households, including many
of the poorest households, had no vehicles.
Lower-Income Households Had Fewer Vehicles
in 1994
Lower-income households--those with annual family
incomes below $25,000--had, on average, 1.5 vehicles in 1994. Not
surprisingly, households with annual family incomes of $25,000 or
above had more vehicles--2.1, on average
More Households in 1994 Had No Vehicles
In 1988 and 1991, the number of households without
vehicles remained at about 10 million, even though the total number
of households rose 3.0 million from 1988 to 1991. In 1991, the share
of households without vehicles was 10.6 percent.
In 1994, by contrast, the share of households without
vehicles jumped to 12.7 percent. The total number of households
rose 2.7 million from 1991 to 1994, while the number of households
without vehicles rose 2.5 million.
The lowest-income households accounted for 83 percent
of the total increase in the number of households without vehicles.
(The lowest-income households are those categorized as eligible
for Federal assistance because their income is lower than 150 percent
of the national poverty line or 60 percent of statewide median income,
whichever is higher.(5)) In 1994, 30 percent of the Nation's lowest-income
households were without vehicles, compared with a national average
for all households of 13 percent.
Changes in Residential Vehicle Technology
The transportation sector relies almost entirely on petroleum.
Because it also accounts for about two-thirds of U.S. total petroleum
demand,(6) passenger cars and light
trucks became a focus of efforts to use petroleum more efficiently,
thereby restraining demand.
The Energy Policy and Conservation Act of 1975 required passenger
car and light truck manufacturers to meet corporate average fuel
economy (CAFE) standards applied on a fleet-wide basis for each
manufacturer.(7) The CAFE standards,
higher fuel prices in the 1970's and 1980's, and environmental quality
initiatives such as the Clean Air Act Amendments of 1990 all contributed
to increasing the demand for more fuel-efficient vehicles.
In turn, the demand for more fuel-efficient vehicles spurred improvements
in existing technologies and the development of new technologies.
For example, using lighter-weight materials and reducing the size
of vehicles led to lighter vehicles that consumed less fuel per
mile.
Many improvements occurred in engine technology. Increasing the
number of valves per cylinder resulted in increased performance
from smaller, more fuel-efficient engines. Increasing the number
of gears in manual and automatic transmissions allowed engines to
operate at peak efficiency more of the time. Similarly, using lockup
torque converters to allow direct drive under some driving conditions
also increased fuel economy.
One of the most far-reaching improvements in engine technology
concerned fuel injection, which was available but not widely used
prior to the mid-1980's. Valued for its greater fuel economy, as
well as for its ability to control carbon monoxide emissions and
to improve engine performance, fuel injection technology began to
penetrate the fleet during the 1980's, and it was improved to such
an extent that after 1990 virtually all new light-duty vehicles
were equipped with fuel injection instead of carburetors. By 1994,
the trend toward the use of fuel injection rather than carburetors
for fuel metering had brought the share of residential vehicles
using fuel injection to nearly half of the total residential fleet.
That share will increase rapidly in future years as older vehicles
are retired.
Engine Size Shrank and Then Increased Slowly
For model year 1975 (the year in which CAFE standards were first
mandated), residential vehicle engine size averaged 293 cubic inches
of displacement.(8) Twelve years
later, the engines were much smaller. Model year 1987 engines averaged
175 cubic inches (Figure 2.7). Thereafter, engine size trended upward,
reaching an average of 198 cubic inches of displacement for model
year 1995.
Sources:
New Vehicle Averages: Environmental Protection
Agency, Light-Duty Automotive Technology and Fuel Economy Trends
Through 1996, EPA/AA/TDSG/96-01 (Washington, DC, August 1996),
Table 1. Fleet Averages: Energy Information Administration
calculations made on the basis of data from the Residential Transportation
Energy Consumption Survey 1988, 1991, and 1994, March 17, 1997.
As
is generally the case, changes in the residential vehicle fleet
as a whole lagged the changes by model year. Of the 3 years for
which fleet data are available, 1991 had the lowest average engine
size (despite an upward trend in the 4 preceding model years). In
1994, the fleet average was 227 cubic inches, while the 1994 model
year average was 196.
Engines
Averaged Fewer Cylinders
Meanwhile,
the average number of cylinders in residential vehicle engines was
decreasing. In 1988, 55 million vehicles, over one-third of the
total residential fleet, had 8-cylinder engines. In 1994, 8-cylinder
engines were found in only about 42 million vehicles, just over
one-fourth of the total (Figure 2.8).
Sources:
1988--Energy Information Administration, Household Vehicles
Energy Consumption 1988, DOE/EIA-0464(88) (Washington, DC,
February 1990), Table 6. 1994--Table 5.1 in this report.
The
trend over the 7-year period was toward more 4- and 6-cylinder engines.
In 1994, 4-cylinder engines were the most common (62 million out
of a total of 157 million), but the 52 million 6-cylinder engines
represented the greatest increase (45 percent) relative to the 1988
level.
Power
and Performance Improved but Fuel Economy Stagnated
The
improvements in residential vehicle technology allowed for improvements
in performance despite shrinking or relatively stable engine size.
However, improved performance came at the expense of improvements
in fuel economy. For example, technical improvement in the efficiency
of engines can be used to provide increased acceleration or smaller,
lighter engines with better fuel economy.
The
effect of the improvements was particularly noticeable over the
1988-to-1994 period, when engine size stayed at or below 198 cubic
inches of displacement but power and performance rose markedly.
For example, the average horsepower of new vehicles rose from 123
in 1988 to 159 in 1994, an increase of 29 percent (Figure 2.9).
Vehicles manufactured in 1994, with an average of 159 horsepower,
had the highest horsepower rating in at least 20 years, a rating
markedly higher than the 20-year low-point of 102 horsepower in
1981.
Source:
Environmental Protection Agency, Light-Duty Automotive Technology
and Fuel Economy Trends Through 1996, EPA/AA/TDSG/96-01 (Washington,
DC, August 1996), Table 1.
Similarly,
the time required for the average residential vehicle to accelerate
from 0 miles per hour to 60 miles per hour was reduced by 1.1 seconds,
from 12.8 seconds in 1988 to 11.7 seconds in 1994. The 11.7 seconds
time was the fastest in at least 20 years.(9)
Over
the same 7 years, however, the average fuel economy of new vehicles
stagnated. Nevertheless, the average fuel economy of the residential
fleet rose somewhat, as new, more fuel-economic vehicles replaced
older, less fuel-economic vehicles (see Chapter 4).
1.
Energy Information Administration, Annual Energy Review
1995, DOE/EIA-0384(95) (Washington, DC, July 1996), Table 1.5.
2.
1988--Federal Highway Administration (FHA),
Highway Statistics 1988, FHWA-PL-89-003 (Washington, DC, September
1989), Table DL-1B. 1994--FHA, Highway Statistics
1994, FHWA-PL-95-042 (Washington, DC, October 1995), Table DL-1B.
3.
"Chained dollars" is a measure used to express real
prices. Real prices are those that have been adjusted to remove
the effect of changes in the purchasing power of the dollar; they
usually reflect buying power relative to a reference year (in this
case, 1992). Prior to 1996, real prices were expressed in constant
dollars, a measure based on the weights of goods and services in
a single year, usually a recent year. In 1996, the U.S. Department
of Commerce introduced the chained-dollar measure. The new measure
is based on the average weights of goods and services in successive
pairs of years. It is "chained" because the second year
in each pair, with its weights, becomes the first year of the next
pair. The advantage of using the chained-dollar measure is that
it is more closely related to any given period covered and is therefore
subject to less distortion over time.
4.
Energy Information Administration, Annual Energy Review
1995, DOE/EIA-0384(95) (Washington, DC, July 1996), Table 5.21.
5.
Energy Information Administration, Household Energy Consumption
and Expenditures 1993, DOE/EIA-0321(93) (Washington, DC, October
1995), p. 296.
6.
Energy Information Administration, Annual Energy Review
1995, DOE/EIA-0384(95) (Washington, DC, July 1996), Table 5.12b.
7.
International Trade Association, "Corporate Average Fuel
Economy Explained." Online. (http://www.ita.doc.gov/industry/basic/cafe.htm)
(March 5, 1997).
8.
Environmental Protection Agency, Light-Duty Automotive Technology
and Fuel Economy Trends Through 1996, EPA/AA/TDSG/96-01 (Washington,
DC, August 1996), Table 1.
9.
Environmental Protection Agency, Light-Duty Automotive Technology
and Fuel Economy Trends Through 1996, EPA/AA/TDSG/96-01 (Washington,
DC, August 1996), Table 1.
File Last Modified: February 1, 2002
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