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Fuel Economy of the Light-Duty Vehicle Fleet |
The U.S. fleet of light-duty vehicles consists of cars and light trucks, including minivans, sport utility vehicles (SUVs) and trucks with gross vehicle weight less than 8,500 pounds. The fuel economy of light-duty vehicles is regulated by the CAFE standards set by NHTSA. Currently, the CAFE standard is 27.5 miles per gallon (mpg) for cars and 20.7 mpg for light trucks. The most recent increase in the CAFE standard for cars was in 1990, and the most recent increase in the CAFE standard for light trucks was in 1996. There has been little improvement in the average fuel economy of new cars and light trucks sold in the United States over the past 15 years (Figure 19), but the combined average fuel economy for all new light-duty vehicles has declined steadily because of an increase in sales of light trucks. Since 1987, the average fuel economy of new light-duty vehicles sold has remained relatively constant, averaging 28.5 mpg for cars and 21.1 mpg for light trucks. For model year 2003, cars achieved the highest measured CAFE to date, averaging 29.4 mpg. The highest light truck CAFE was achieved in 1987 at 21.7 mpg, but light truck CAFE has been increasing in recent years, to 21.6 mpg for model year 2003 [87]. The fuel economy of light trucks is expected to improve over the next 3 years, because NHTSA announced new standards in April 2003 that increased the requirements to 21.0 mpg for model year 2005, 21.6 mpg for model year 2006, and 22.2 mpg for model years 2007 and beyond. Although the relatively flat fuel economy for cars and light trucks over the past 15 years may suggest little technological improvement, this is not the case. Instead, technological advances have led to significant improvements in vehicle performance and increases in vehicle size, while generally maintaining or slightly increasing fuel economy. Based on NHTSA data, the average new car in 1990 achieved 28.0 mpg, had a curb weight of 2,906 pounds, and produced 132 horsepower. In 2002, average new car fuel economy was 3.2 percent higher at 28.9 mpg, curb weight was 8.7 percent higher at 3,159 pounds, and engine size was 30.0 percent higher at 171 horsepower [88]. Thus, although fuel economy improvements have been minimal, the introduction of advanced technologies (including variable valve timing and lift, electronic engine and transmission controls, lock-up torque converters, and five-speed automatic transmissions) have produced significant improvement in engine and transmission efficiency, allowing substantial increases in new car size and performance. Data from the EPA show similar performance trends. For example, from 1990 to 2002, average new car horsepower per cubic inch displacement, a measure of engine efficiency, increased by 28.6 percent, from 0.83 to 1.07, as a result of implementation of advanced technologies and improved engine designs [89]. Similar improvements in vehicle attributes have also occurred for light trucks. In 1990, the average new light truck achieved 20.8 mpg, had a curb weight of 4,005 pounds, and produced 151 horsepower. In 2002, the average fuel economy for new light trucks was 4.8 percent higher at 21.8 mpg, curb weight was 13.5 percent higher at 4,547 pounds, and engine size was 45.7 percent higher at 220 horsepower. As in the case of cars, manufacturers have provided improved fuel economy for light trucks while increasing vehicle size and performance by implementing advanced technologies. From 1990 to 2002, light truck horsepower per cubic inch displacement increased by 37.4 percent, from 0.67 to 0.92. In addition to increases in weight and performance, the mix of new vehicles sold has changed dramatically over the past 20 years. In 1983, cars accounted for 76.5 percent of new light-duty vehicles sold; in 2003, they accounted for only 47.2 percent. In addition, sales of subcompact cars, as a percent of total new vehicles sold, decreased from 20.5 percent in 1983 to 2.8 percent in 2003. Compact, midsize, and large car sales as a percent of total new light-duty vehicle sales have also declined. Since 1983, sales of new light trucks, including SUVs, have increased significantly. In 2002, light trucks made up the majority of new light-duty vehicle sales. Increases in light truck sales over the past 20 years can be attributed to increased consumer demand for vehicle utility, seating capacity, ride height, and perceived safety. Coupled with low fuel prices, this trend has provided a favorable market for new light trucks, with sales of SUVs and minivans accounting for most of the increase in light truck sales. In 1983, SUVs accounted for 2.9 percent of new light-duty vehicle sales; in 2003, SUVs accounted for 27.0 percent of new light-duty vehicle sales and represented the largest segment of the light-duty vehicle market. Similarly, sales of minivans have grown dramatically. In 1983, minivans accounted for 0.1 percent of new light-duty vehicle sales; in 1994, they reached a peak share of 9.2 percent; and in 2003 their share was 6.5 percent of new light-duty vehicle sales [90]. Although significant improvements have been made in light-duty vehicle engine and transmission efficiency, consumer demand for increased performance and vehicle size, coupled with the growth of the light truck market, has resulted in an average new light-duty vehicle fuel economy that peaked at 26.2 mpg in 1987. New light-duty vehicle fuel economy declined steadily throughout the 1990s, to a low of 24.5 mpg in 1999, followed by an increase to 25.0 mpg for model year 2003 vehicles. The AEO2005 reference case projects that, in addition to increases in market penetration of advanced technologies, sales of hybrid and diesel vehicles will continue to increase. As a result, new car fuel economy in 2025 is projected to average 31.0 mpg, and new light truck fuel economy is projected to average 24.6 mpg—increases of 5.4 percent for cars and 14.1 percent for light trucks over the respective model year 2003 CAFE levels. Similar to historic trends, average engine power output is projected to increase to 215 horsepower for new cars sold in 2025 (26.3 percent higher than model year 2003) and 243 horsepower for new light trucks sold in 2025 (18.0 percent higher than model year 2003). Light truck sales are projected to account for 58.6 percent of new light-duty vehicle sales in 2025, and as a result the average fuel economy for all new light-duty vehicles sold is projected to increase by 7.2 percent, to 26.9 mpg in 2025. Recent introductions of more efficient crossover vehicles (SUVs with design features more similar to those of cars than trucks), increasing consumer interest in environmentally friendly vehicles, the possibility of sustained high fuel prices, and increasing consumer demand for improvements in vehicle performance and luxury all will influence the future of light-duty vehicle sales and fuel economy. In addition, carbon emission regulations for light-duty vehicles that have been issued in eight U.S. States and Canada would require improvements in vehicle fuel economy starting in 2009 that go beyond those required by current U.S. CAFE standards. (AEO2005 does not include the impact of these carbon emission regulations, because their future is uncertain. The auto industry has filed suit against the regulations established in California, contending that only the Federal Government has the authority to set vehicle fuel economy standards. See “Legislation and Regulations,” page 27.) NHTSA is also considering modification of light truck CAFE standards, which could result in the redefinition of a light truck as well as a restructuring of the standards to be based on vehicle weight and/or size. In summary, considerable uncertainty surrounds the future of light-duty vehicle fuel economy. Fuel prices, the market success of hybrid and diesel vehicles, continued increases in consumer demand for light trucks and better vehicle performance, potential new fuel economy standards, and future regulation of carbon dioxide emissions all have potentially significant impacts on the automobile industry and the vehicles that will be manufactured and sold in the future.
Contact: John Maples |
