Process for adjusting the height of the head rest of an automotive vehicle seat.

The car seat head rest (2) contains two infra-red sensors (8), mounted one above the other. These detect the presence of a passenger and operate a motor which raises the rest on its supports (3), lowering it when the seat is empty. Independent claims are included for: (a) a method for regulating the height of the head rest; and (b) a car fitted with the head rest.