DESIGN APPROACH AND CRASH PERFORMANCE OF AUTOMATIC SEAT BELT SYSTEMS.

The passive or automatic seat belt involves a minimum of hardware changes to the belt system. The center line anchor location for the upper torso belt is the most major change which affects the auto's structure. It should be a center line mounting for maximum passenger convenience. The hardware changes in the belt system are primarily caused by additional webbing storage requirements, withdrawal action and relocation of the lap belt retractor into the door. A free-spooling emergency release is designed into the lap belt retractor. Crash simulation testing indicates low elongation webbing is desirable for the automatic belt system. Performance under dynamic testing reveals no significant variations from conventional lap/shoulder belt testing. Injury criteria established by FMVSS 208 can be met, but reproducibility of test results between different crash simulators is questionable.