Abstract
The most occurring injury in rear end collisions is the whiplash injury. Most modern cars have head rests which prevent whiplash injuries in case of such an accident, but whiplash injuries still occur. Obviously the preventive working of head rests is imperfect. The aim of this report is to show the influence of head rests in the prevention of whiplash injury, and how the efficiency can be increased. Most head rests are not installed in the right position and not fitted to the position of the head. The horizontal and vertical distance between the head rest and the head are the most important to prevent injuries.