Impact detecting arrangement for vehicle safety device

A door (1) of a motor vehicle has a deformable outer skin (3), an intermediate panel (4) which is relatively strong and a relatively weak inner trim (5). A force transmitting element (7) is provided in the door with a part (9) thereof passing slidably through an aperture (13) formed in the intermediate panel (4). The force transmitting element (7) serves to transmit an impact on the outer skin (3) of the door to a sensor (16) mounted on a seat (2) within the vehicle to activate a safety device such as an air-bag.