Seat design and utilization of carry over seat systems may limit the ability of the seat system to absorb energy during impact. For this reason, head restraints are being designed to meet new safety standards through the relationship to the occupant's head. With the head restraint being designed to meet safety guidelines, comfort criteria may be sacrificed. Industry feedback indicates that small females are more negatively affected by the head restraint designs that meet the new safety standards. Studies indicate that many occupants do not adjust the head restraint at all, leading to the question should the head restraint sacrifice comfort to meet safety requirements [1, 10]? There were two goals established for this study. First, determine the percentage of occupants who do adjust the head restraint and to what height. Second, simulating various occupant postures in Jack, determine if a predictive value or posture can be created to aid in head restraint designs that meet safety and comfort requirements.
Data were collected over a five-day period, in a Compact Utility Vehicle (CUV), from 73 female and 17 male participants. Of all 90 participants only 35% adjusted their head restraint. 90% of the participants would have been able to adjust the head restraint to a safe height based on the center of gravity of the head and the adjustment range of the head restraint. A positive correlation between backset and seated height exists for only the large female, medium male, and large male sample sizes. When simulated in Jack, neither the CAD simulated backset measurement, nor the recorded participants' backsets, were predicted by the driving postured manikin.