Neck injuries resulting from rear end car impacts have attracted increasing attention in recent years. Although usually not life-threatening these injuries can have long-term consequences. The exact mechanism of injury has not yet been established. Several probable mechanisms occurring at different phases during the crash sequence have been suggested by researchers.The accident experience with existing seat and head restraint designs is summarized. The results show that there are many factors influencing the risk of neck injury. A high and fixed-in-position head restraint, positioned close to the head, is beneficial. Also, Individual factors, such as gender and height, and seating position, are shown to have influence on the injury risk.Based on the range of biomechanical research in the area, as well as results from accident investigations and mathematical simulations, biomechanical guidelines and engineering requirements are proposed, with the aim of reducing the risk of neck injuries in a rear end impact. The guidelines and requirements focus on the performance of the whole seat.A new seat concept, WHIPS (Whiplash Protection Study), developed using these guidelines and requirements, is explained.Results of dummy and sub-system tests with the new concept are presented, as well as results of computer simulations with a human-like occupant model. The results, seen in relation to the suggested engineering guidelines, show a considerable potential for reduced neck injury risk in rear end impacts.