In January 2001, the National Highway Traffic Safety Administration (NHTSA) issued a Notice of Proposed Rulemaking (NPRM) concerning the regulation of automobile head restraints in Federal Motor Vehicle Safety Standard (FMVSS) 202. This report presents analyses of occupant posture and position data that were conducted in preparation for comments from the University of Michigan Transportation Research Institute (UMTRI) on the NPRM. The focus of this report is on the potential impact of head restraint geometry requirements on the accommodation of vehicle occupant head positions in normal driving and riding postures. This report makes specific recommendations for head restraint geometry and measurement procedures. The analysis in this report indicates that head restraints on seats with adjustable seatback angles should extend at least 730 mm above the H-point (vertically, not along the manikin torso line as specified in the NPRM). The head restraint profile below this height should lie entirely forward of a line 315 mm rearward of the H-point. An analysis of driver postures indicates that it is not possible for a head restraint that rotates with the seatback to produce a mean driver backset of less than about 70 mm, because to do so would disaccommodate a substantial number of drivers' preferred head positions. Further reductions in driver backset will require new solutions to head restraint positioning. (Author/publisher)
Samenvatting