|Air carrier, large certificated, domestic, all services||General aviation||Highway||Transit
KEY: N= data do not exist; U= data are unavailable.
NOTES: General aviation data include all operations other than those operating under 14 CFR 121 and 14 CFR 135. Data for 1996 are not comparable to earlier years. Transit rail modes are measured in car-miles. Car-miles measure individual vehicle-miles in a train. 2003 transit data are preliminary. A train-mile is the movement of a train, which can consist of multiple vehicles (cars), the distance of 1 mile. This differs from a vehicle-mile, which is the movement of 1 vehicle the distance of 1 mile.
SOURCE: Various sources, as cited in U.S. Department of Transportation, Research and Innovative Technology Administration, Bureau of Transportation Statistics, National Transportation Statistics 2006, table 1-32, available at http://www.bts.gov/, as of March 2006.