A hybrid car like a Toyota Prius has an internal combustion engine, an electric motor that doubles up as a starter motor and as a battery regenerator, and a special big battery. That big battery can hold enough for the car to drive a short distance at low speed on its electric motor alone, but just a short distance. After that, the IC engine cuts in and the car is propelled by a mix of the IC engine and the regenerative electric motor. The regenerative electric motor generates electricity when the car is coasting, decelerating or descending inclines and stores that electricity in the battery. The electric motor assists the IC motor under hard acceleration (not recommended) and may take over for short periods at slowish cruising speeds. Hybrid systems work better in towns when there is more scope for regeneration under deceleration when slowing down in stop/start traffic than it does on a long motorway run. Consequently hybrids are more suitable for city use than diesels and diesels more suitable for long distance use than hybrids.