Table 11,,,,, Passenger-Miles,,,,, (Millions),,,,, Mode,1970,1980,1990,2000,2002 Air carriers,"108,442","204,368","345,873","516,129","483,057" General aviation,"9,100","14,700","13,000","15,200",U Passenger cars,"1,750,897","2,011,989","2,281,391","2,544,457","2,604,065" Motorcycles,"3,277","12,257","12,424","11,516","11,655" "Other 2-axle, 4-tire vehiclesa","225,613","520,774","999,754","1,467,664","1,719,750" Busesb,N,N,"121,398","160,919","145,208" Rail:,,,,, Transitc,N,"10,939","12,046","15,200","P15,095" Commuter,"4,592","6,516","7,082","9,402","P9,504" "Intercity/ Amtrakd","6,179","4,503","6,057","5,498","5,468" Other transite,N,390,841,"1,631","P1,696" "a Includes vans, pickup trucks, sport utility vehicles, and other 2-axle, 4-tire vehicles that are not passenger cars.",,,,, "b Includes municipally owned transit, commercial, federal, and school buses.",,,,, c Includes light and heavy rail only.,,,,, d Fiscal year data. Amtrak began operations in 1971.,,,,, "e Includes demand responsive, ferryboat, and other transit not specified; 1980 data include ferryboat and “other transit” only.",,,,, Key: N = data are nonexistent; P = preliminary; U = unavailable.,,,,, "Sources: Except as noted, various sources, as cited in U.S. Department of Transportation (USDOT), Bureau of Transportation Statistics (BTS), National Transportation Statistics, table 1-37, available at http://www.bts.gov (latest data forthcoming). 2002 air carriers—USDOT, BTS, Air Carrier Traffic Statistics (Washington, DC: Annual December issues), p. 2, line 1.",,,,,