Japanese Kei motorcycles are the smallest highway-legal passenger cars, created by the Japanese government in 1949 and are one type of microcar, which are generally known as a small fuel-efficient automobile, which can have three or four wheels.
Kei car (or keijidosha , "light automobile", pronounced [kedidoa), known variously outside Japan as Japanese city car, ultramini, or Japanese microcar, is the Japanese vehicle category for the smallest highway-legal passenger cars. Similar Japanese categories exist for microvans, and Kei trucks. 
