 New models of the Ford Expedition have a computer-controlled system designed for convenience, which lowers automatically when the doors are unlocked by remote, returns to normal height when the vehicle is started, and (on 4-wheel-drive models), raises when the 4x4 system is engaged.Some cars use these systems to improve the vehicle's handling by lowering the vehicle's height during higher speeds a current example being the Mercedes-Benz Active Body Control system.Another example is the Audi A8, which when driven at speeds of more than 120 km/h for more than 30 seconds reduces its clearance from 120 mm to 95 mm.