There have been documented cases of rollover accidents wherein the driver was ejected while wearing the single loop lap/shoulder harness. In this paper, three actual incidents are discussed. In two of the three cases the vehicle was photographed at the accident scene with the latchplate still in the buckle, whereas in the other case, the evidence of the seat belt having been latched was found some time after the accident. The design of the seat belt retractor is analyzed to determine its role in the retention of occupants in a rollover collision. The nature of rollover acceleration pulses and occupant motions are discussed. The design of the typical retractor mechanism, particularly the ones in the three accident scenarios is presented. A review of current seat belt retractors is also presented with commentary on which designs may prevent this kind of release.
Abstract