Annual highway vehicle-miles of travel (vmt) amounted to 2,856 billion in 2002, rising by 27 percent since 1992, an average annual increase of 2.4 percent. Vmt per capita rose by 13 percent during the same period, an average annual increase of 1.2 percent .
In recent years, the makeup and use of the highway vehicle fleet in the United States has changed, altering the share of vmt by vehicle type (figure 2-16). With the increasing popularity of sport utility percent) between 1992 and 2002. However, during the same period, freight vehicle vmt (single-unit and combination trucks) grew 40 percent, outpacing total passenger vehicle vmt growth (26 percent). Nevertheless, in 2002, passenger vehicles accounted for more than 90 percent of highway vmt.
Vehicle travel1 has also generally increased in other modes of transportation including rail, air, and rail transit. Vehicle-miles by rail (measured in train-miles and excluding transit rail) grew 27 percent between 1992 and 2002, an average annual increase of 2.4 percent. Freight train-miles made up over 90 percent of all rail vehicle travel in 2002. This share increased slightly between 1992 and 2002 as freight rail vehicle movements outpaced those of passenger rail over the period (figure 2-17).
Domestic service air carrier aircraft vmt increased by 41 percent between 1992 and 2002, an average annual increase of 3.5 percent. Air carrier aircraft vmt peaked in 2000 at 5,664 million, falling back to 5,550 million in 2001, mainly because of the terrorist attacks that year. Aircraft vmt increased again in 2002 reaching 5,612 million .
The biggest change in rail transit between 1992 and 2002 was a doubling of light rail vmt as existing systems were expanded and new systems were built (e.g., in Baltimore, Dallas, Denver, St. Louis, and Salt Lake City). The average annual increase over this period was 7.7 percent (figure 2-18). Commuter rail vehicle-miles were up 30 percent over this period and heavy rail miles, 18 percent. This is an average annual increase of 2.6 percent for commuter rail and 1.7 percent for heavy rail.
1. U.S. Department of Commerce, U.S. Census Bureau, Statistical Abstract of the United States: 2003 (Washington, DC: 2003), table 2 (resident population), also available at http://www.census.gov/statab/www, as of April 2004.
2. U.S. Department of Transportation, Bureau of Transportation Statistics, Air Carrier Traffic Statistics (Washington, DC: Annual December issues).
1 A vehicle-mile of travel (1 vehicle traveling 1 mile) is a concept that is more easily applied to highway vehicles than to other modes of transportation. For instance, rail can be measured in car-miles (1 car, 1 mile) or in train-miles, which includes any number of cars but may be more comparable to highway vmt. For air transportation, vmt is synonymous with an aircraft-mile of travel (1 aircraft, 1 mile).