bus, Large motor vehicle designed to carry passengers usually along a fixed route according to a schedule. The first gasoline-powered bus was built in Germany in 1895 and carried eight passengers. The first integral-frame bus was constructed in the early 1920s in the U.S. In the 1930s diesel engines were introduced, providing greater power and fuel efficiency to larger buses. With the development of highway systems, transcontinental bus lines became common in North America. Double-decked buses are used in some European cities; articulated buses pull trailers with flexible joints. Trolley buses, whose electric motors draw power from overhead wires, are now used mostly in European cities.