Head-rests develop their protective function in rear-end collisions, where they reduce the danger of collision between front- and rear-seat occupants. Beyond that they mitigate the so-called "whiplash effect", which occurs during a front-end collision with occupants held by seat belts. In the case of rear-end collisions they assist in reducing or tempering injuries such as disc damage, spinal cord compression and similar, caused by the backward jerking of the head. By using a suitable head-rest in association with a seat belt a head-on collision of up to 70 km/hr can be withstood without significant injuries. All these positive points are subject to certain disadvantages; headrests reduce visibility. Moreover the effectiveness of the head-rest is dependent upon its connection with the seating framework and upon the potential to adjust it to suit the individual occupant. At the present time, there is no universally applicable standard and this has the effect of stopping the introduction of compulsory head-rest use.
Abstract