Modulation of the occupant's movement within the vehicle by the seat belt reduces the potential for striking certain structures and decreases severity of the injuries. The seat belt also functions to direct the upper torso, especially the head, to specific interior surfaces. Design modifications of these areas are needed to prevent serious facial fractures that have been seen. Lap belted drivers contact the steering wheel rim or instrument panel in front of the wheel in head-on crashes; the front passenger strikes the upper instrument panel. Improper positioning of the lap seat belts produces serious intraabdominal injury, especially in the case of the rear passengers. Seat belt fatality cases were, in general, due to collapse and compromise of the occupant space as typified by the broadside intersection collision.