Bus (vehicle), self-propelled, trackless, automotive vehicle that carries passengers, often along a specified route as part of a public transportation system (see Public Transportation). Millions of people rely on buses for daily transport or longer trips. The term bus is short for the French word omnibus, which refers to a slow or local train.
Municipal buses are usually operated by local or state transit agencies and are supported by passenger fares and public funds. While buses range widely in size and form, depending on their function, the standard bus ranges in length from 10.7 m (35.0 ft) to 12.2 m (40.0 ft) and can carry more than 50 seated passengers. Some buses are articulated, trailing an additional unit via flexible joints. Double-decker buses have a second, and sometimes third, riding level. Riders pay a fare with cash or tokens on the bus, or they may purchase passes, prior to entering the bus, for a specific period of time.
Other types of buses in the United States include school buses and commercial buses. School buses, often recognizable by their bright orange-yellow color, transport students to and from school. Commercial bus lines, which depend solely on fares for profit, may serve routes not accessible by other forms of public transit.
Buses may use gasoline, diesel fuel, natural gas, or overhead electrical power (the latter is sometimes called a trolleybus or trackless trolley). In addition, a few municipalities have started experimenting with hydrogen fuel cells as a power source (see Fuel Cell).
In 1662 French scientist and philosopher Blaise Pascal and a colleague established a horse-drawn bus service in France. The project failed, but horse-drawn bus service reappeared in Paris in 1819, with other major cities copying the idea within a few years. While improvements were made during the 19th century to such devices as the steam engine and the internal-combustion engine, by the turn of the century most buses were still horse-drawn.
In 1905 the Fifth Avenue Coach Company in New York City instituted a motorized bus service, using the modified form of an automobile. Most buses thereafter consisted of bus bodies mounted on truck chassis, or frames. By 1930 thousands of bus services, including many one-vehicle companies, were operating, making significant inroads in streetcar use. In that year, many of the larger, interstate bus collectives were consolidated into the Greyhound Corporation. Better roads and tires improved bus service, and service grew rapidly in the 1930s and 1940s. In the 1950s buses gained air suspension and additional rear axles to improve rides (see Suspension System).
Beginning in the 1940s, the use of automobiles and, to some extent, airplanes, began displacing the use of buses. Buses are still, however, the most-used form of mass transit in the United States. Governments often promote the use of buses because they are comparatively environmentally sound, inexpensive, and safe, and they help cut down on traffic congestion.