A vehicle is a form of transport (public or private) that carries a person or people over a distance of any length. The term "vehicle" is commonly used to refer to a motorised vehicle, i.e. a vehicle that is propelled by an engine (e.g. car, bus, metro, train, tram, RER, cable-car, boat, elevator, etc.). However, the term may also be applied to bicycles, roller skates, skateboards, skis, ice skates, etc., i.e. vehicles that move under human propulsion.
While the term is commonly used and easy to understand, its legal definition is more problematic when it comes to accident investigations. In such cases, the term "vehicle" refers to any machine capable of moving under its own propulsion (e.g. an engine, animal traction, a sail, oars or a pedal drivechain). This definition covers terrestrial, maritime, airborne and river-borne vehicles.
In everyday language, the word "vehicle" is often synonymous with the car or other such vehicle, whether motorised or not, although the following are also considered to be vehicles: sledges, scooters, hand-drawn carts, kayaks, pedalos, planes, trucks, caravans, paragliders and even orbiting satellites. Vehicles are therefore categorised by type of propulsion (animal, human or motor), as well as by type of traction (wind, gravity, inertia, etc.) or by method of propulsion (drive wheel, jet engine, etc.).