Detailed Vehicles Definitions

• General aviation reflects active fleet only.
• Air carrier aircraft include those carrying passengers or cargo for hire under 14 CFR 121 and 14 CFR 135. Beginning in 1990, the number of aircraft is the monthly average of the number of aircraft reported in use for the last three months of the year. Prior to 1990, it was the number of aircraft reported in use during December of a given year.
• 1991-94 General Aviation data revised to reflect changes in adjustment for nonresponse bias with 1996 telephone survey factors; 1995-97 data may not be comparable to 1994 and earlier years due to changes in methodology. Includes air taxi aircraft. Beginning in 2004, commuter activity is excluded from all estimates. Commuter activity was included in the air taxi use category in 2003 and prior.
• Highway total reflects registered vehicles only.
• Surface vehicle data for 2007-10 were calculated using a new methodology developed by FHWA. Data for these years are based on new categories and are not comparable to previous years. The new category Light duty vehicle, short wheel base replaces the old category Passenger car and includes passenger cars, light trucks, vans and sport utility vehicles with a wheelbase (WB) equal to or less than 121 inches. The new category Light duty vehicle, long wheel base replaces Other 2-axle, 4-tire vehicle and includes large passenger cars, vans, pickup trucks, and sport/utility vehicles with wheelbases (WB) larger than 121 inches. Data for 1960-2006 are not comparable to data for 2007-11.
• In 1960, Truck, single-unit 2-axle 6-tire or more includes all Trucks and Other 2-axle 4-tire vehicles.
• In 1965, other 2-axle 4-tire vehicle data included in all Trucks.
• Transit ; bus figure is also included as part of bus in the Highway category. Beginning in 2011, Motor bus includes Bus, Bus Rapid Transit, and Commuter Bus.
• Beginning in 2011, Light rail cars includes Light Rail, Street Car Rail, and Hybrid Rail.
• Bus and Demand responsive in these tables refer to a mode of service, not to a specific vehicle type. Demand responsive service, defined as roadway service directly from an origin to a destination determined by the rider and not following a fixed-route, is usually provided by vans, small buses and in a limited number of cases by large buses. Bus service is a variety of roadway services that share the characteristic of being entirely or partially fixed routes. Bus service includes local service, express service, subscription service, diversionary route service, loop service, and other types. Although Bus service is normally provided by buses, it can be provided by smaller vehicles that may be considered large vans.
• Prior to 1984, transit excludes most rural and smaller systems funded via Sections 18 and 16(b)(2), Urban Mass Transportation Act of 1964, as amended. Also prior to 1984, includes total vehicles owned and leased.
• Other transit includes Alaska railroad, aerial tramway, automated guideway transit, cable car, ferry boat, inclined plane, monorail, and vanpool.
• Transit data for 1996 and later years are obtained from the National Transit Database and cannot be compared with data for earlier years.
• Nonself-propelled vessels include dry-cargo barges, tank barges, and railroad-car floats. Data for Jan. 1, 1991-June 30, 1991 are included in the 1990 figure.
• Self-propelled vessels include dry-cargo and/or passenger, offshore supply vessels, railroad-car ferries, tankers, and towboats.
• 1960-2006 oceangoing self-propelled vessels (1,000 gross tons and over) data includes private and government owned vessels of 1,000 gross tons and over. Beginning in 2007, data are reported only for privately-owned vessels of 1,000 gross tons and over. Calendar Year 2009 includes privately owned vessels of 10,000 deadweight tons and above not including the Great Lakes vessels. All the data are year-end data.
• Recreational boats include vessels that are required to be numbered in accordance with Chapter 123 of Title 46 U.S.C.