Passenger travel was 5 percent more energy efficient in 2000 than in 1990 (figure 117), mainly due to gains by domestic commercial aviation. Improved aircraft fuel economy and increased passenger loads resulted in a 32 percent increase in commercial air passenger energy efficiency between 1990 and 2000 . Aircraft fuel economy improved by 20 percent between 1990 and 2000. Domestic commercial air passenger-miles rose 49 percent between 1990 and 2000, while energy use grew 13 percent .
Highway passenger travel—by automobiles, motorcycles, and light trucks—represented 85 percent of all passenger-miles and 91 percent of passenger travel energy use in 2000. Highway travel was 2 percent more energy efficient in 2000 compared with 1990 . This gain was due to a 6 percent increase in the energy efficiency of passenger cars and motorcycles, offset by a 5 percent loss in efficiency of light trucks1. Furthermore, light truck passenger-miles grew 47 percent between 1990 and 2000, compared with 12 percent for passenger cars and 22 percent for all highway passenger vehicles.
Freight energy efficiency (ton-miles per BTU) declined 7 percent from 1990 to 2000 (figure 118). The decline in freight energy efficiency occurred as a result of 2 percent average annual growth rate in ton-miles paired with a relatively rapid average annual growth rate of 3 percent in freight energy consumption. Contributing to this trend was the decline in the energy efficiency of the freight truck and waterborne modes .
See box for Terms Used and Calculations Made
1. U.S. Department of Transportation, Bureau of Transportation Statistics, National Transportation Statistics 2002 (Washington, DC: 2002), calculation based on tables 1-34, 1-44, 4-6, and 4-8, also available at http://www.bts.gov/, as of May 2003.
2. U.S. Department of Transportation, Bureau of Transportation Statistics, Transportation Energy Efficiency Trends in the 1990s, Issue Brief, available at http://www.bts.gov/, as of May 2003.
1 Light trucks include minivans, pickup trucks, and sport utility vehicles.