The seat belt is able to tighten and firmly secure the passenger, reducing sideways and forward movement. It aims to reduce the chance of passengers moving about in the cabin.
Using an electric motor, the buckle itself is capable of increasing tension by up to 80mm when Pre-Safe is activated. For added convenience, this same mechanism extends out by 70mm to assist in buckling up upon entry to the vehicle.
Once the belt is locked in, the buckle retracts and takes up unnecessary slack. This function, up until now, has only been available on front seat belts. Prof. Dr. Ing. Rodolfo Schöneburg, head of passive safety and vehicle functions at Mercedes-Benz Cars, says,
