Estimated passenger-miles of travel (pmt) in the United States increased 24 percent between 1990 and 2000 (see box). Pmt totaled an estimated 4.7 trillion in 2000,1 about 17,000 miles for every man, woman, and child [2, 3].
Just over 85 percent of passenger travel in 2000 was made in personal vehicles (passenger cars and light trucks, including sport utility vehicles, pickups, and minivans) (figure 4). Most of the balance (11 percent) occurred by air. Passenger travel in light trucks accounted for a little under one-third of all pmt. Transit, excluding bus transit, made up less than 1 percent of pmt in 2000; with transit bus included, it accounts for 4 percent.
Travel increased every year between 1990 and 2000 at an annual average rate of 2 percent . Pmt by air and by light truck grew the fastest over this period, at 4 percent per year on average (figure 5). Pmt by intercity train (Amtrak) declined, although there has been modest growth since 1996. Likewise, transit pmt has grown since the mid-1990s.
Passenger travel has increased during the 1990s for a variety of reasons. The resident population of the United States grew by nearly 33 million people over this period . Moreover, the economy also grew significantly. Gross Domestic Product (GDP) increased by 37 percent2 and GDP per capita grew 21 percent between 1990 and 2000 (figure 6) .
1. U.S. Department of Commerce, Bureau of Economic Analysis, National Income and Product Accounts, summary GDP table, available at http://www.bea.doc/bea/dn1.htm, as of May 2003.
2. U.S. Department of Commerce, U.S. Census Bureau, Statistical Abstract of the United States: 2002 (Washington, DC: 2003), for population data.
3. U.S. Department of Transportation, Bureau of Transportation Statistics, National Transportation Statistics 2002 (Washington, DC: 2003), table 1-34, also available at http://www.bts.gov/.
1 This calculation excludes travel in heavy trucks, by bicycle, by walking, and by boat (including recreational boat). Pmt in heavy trucks is excluded because such travel is assumed to be incidental to the hauling of freight, the main purpose of such travel. Bicycle, pedestrian, and boat travel are excluded because there are no national estimates available on an annual basis.
2 Calculation is based on chained 1996 dollars.