A motor vehicle is a vehicle whose propulsion is provided by an engine (or "motor") or other mechanically propelled system which is carried on the vehicle. The internal combustion engine is the most common motor choice, although electric motors or other types are sometimes used. Motor vehicles or road vehicles typically run on public roads.
The rules of the road are laws or practices which all road users must obey; many relate specifically to motor vehicles or subtypes of them. Some common types of motor vehicle: In the United States, a motor vehicle is "a vehicle, not run on rails, that is designed to be self propelled or propelled by electric power obtained from overhead trolley wires, but does not include a motor assisted cycle."[citation needed]