An autonomous vehicle is one that partially or fully drives itself. In a semi-autonmous mode, this may aid particular manoeuvres such as parallel parking, or driving within lane markings on a long drive. In fully autonomous mode, the car also has to deal with ever changing road conditons; other road users including pedestrians and other vehicles; and hazards such as a child or animal running into the road. This usually involves a combination of vision and other sensors linked to rapid response planning and hazard avoidance.