A wedge-shaped component in the seat helps to ensure that the driver and front passenger do not slip beneath their lap belts during a collision or if the brakes are fully applied suddenly and with force.
Together with the seatbelt, belt latch tensioner and belt force limiter, this anti-submarining protection forms part of the BMW restraint system. In the event of a collision, this system can reduce the force of an impact on a car's occupants by up to 50 per cent compared with conventional protection systems.
