Response of Reclined Post Mortem Human Subjects to Frontal Impact

The prospect of a vehicle occupant sustaining injury in a crash is dependant on many factors, including deceleration, restraint availability, restraint usage, vehicle interior geometry, and seating configuration. The relationship between these factors and injury potential has been determined by testing post-mortem human subjects and anthropomorphic test devices to evaluate occupant response to impact. Such testing by the host of researchers studying occupant injury has generated information on occupant response to impact covering a wide range of factors influencing injury outcome.

There has been little testing performed with the seatback reclined from the normal position. As a result, little is known of the response of a vehicle occupant in this configuration beyond the obvious potential of the pelvis to submarine under the lap belt. There exists a need to study occupant response with a reclined seatback when submarining is not present. The objective of this study is to quantify the response of postmortem human subjects with a reclined seatback in the absence of submarining. This is achieved by tilting the entire seat back but staying well short of a recumbent position.

Post-mortem human subject instrumentation allowed measurement of head and spinal acceleration as well as high-speed video. The results showed minimal injury related to the impact conditions with all observed injuries attributable to the health of the test subjects. Significant load sharing occurred between the lap/shoulder belt and the seat cushion allowing the seat cushion to provide a major portion of the restraint. This is in contrast to a traditional lap/shoulder restraint where the vast majority of the restraint is applied by the belts alone.