4-2,,,,
"Number of Aircraft, Railcars, Vehicles, and Vessels",,,,
Mode,1980,1990,2000,2004
Air,,,,
Air carrier,"3,808","6,083","8,055","8,186"
General aviation,"211,045","198,000","217,533","219,426"
Highway,,,,
Automobiles,"121,600,843","133,700,496","133,621,420","136,430,651"
"Other 2-axle, 4-tire vehiclesa","27,875,934","48,274,555","79,084,979","91,845,327"
"Buses (municipally owned transit and commercial, federal, and school buses)","528,789","626,987","746,125","795,274"
Motorcycles ,"5,693,940","4,259,462","4,346,068","5,780,870"
Trucks,,,,
Single-unit,"4,373,784","4,486,981","5,926,030","6,161,028"
Combination,"1,416,869","1,708,895","2,096,619","2,010,335"
Rail—Passenger,,,,
Amtrak–Cars,"2,128","1,863","1,894","1,211"
Amtrak–Locomotives,419,318,378,276
Commuter railcars and locomotives ,"4,500","5,007","5,498","P6,228"
Transitb,"10,654","11,332","12,168","P12,480"
Rail—freight,,,,
Class I–Freight cars,"1,168,114","658,902","560,154","473,773"
Class I–Locomotives,"28,094","18,835","20,028","22,015"
Other freight cars,"542,713","553,359","820,642","814,147"
Waterborne,,,,
"Nonself-propelled vessels (barges)c,d","31,662","31,209","33,152","31,296"
"Self-propelled vesselsc,d","7,126","8,236","8,202","8,994"
"Oceangoing shipsd (1,000 gross tons and over)    ",864,636,454,412
Recreational boats (numbered boats),"8,577,857","10,996,253","12,782,143","12,781,476"
"a Includes vans, pickup trucks, sport utility vehicles, and other 2-axle, 4-tire motor vehicles that are not passenger cars.   ",,,,
b Includes light and heavy rail transit only.   ,,,,
c See Glossary for definitions.   ,,,,
d U.S.-flag vessels.   ,,,,
Key: P = preliminary,,,,
"Sources: Except as noted, various sources, as cited in U.S. Department of Transportation, Research and Innovative Technology Administration, Bureau of Transportation Statistics, National Transportation Statistics, table 1-11, available at http://www.bts.gov, as of October 2006.",,,,
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