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. Biomechanical guidelines and test methods are presented, being part of the results of Volvo's Whiplash Protection Study (WHIPS). The biomechanical guidelines are based on an extensive review of accident experience and biomechanical research aimed at reducing the risk of neck injuries in rear end impacts. A new seat concept, the WHIPS seat, developed using these guidelines and requirements, is explained in detail. The WHIPS seat comprises new recliners as well as a modified backrest and head restraint. The WHIPS recliner is designed to give a controlled rearward motion of the backrest in a rear end impact; thereby improving the closeness to the occupant's head and back, absorbing energy and reducing the occupant's forward rebound. Test results are summarized, and, seen in relation to the suggested engineering guidelines, show a considerable potential for improved neck injury protection in rear end impacts. (A)
Abstract