Automotive Restraint Loading Evidence for Moderate Speed Impacts and a Variety of Restraint Conditions

One of the principal tools used by the accident reconstructionist to determine whether a vehicle occupant was properly restrained when an accident occurred is the examination and analysis of impact evidence and damage to interior structures of the vehicle. Careful analysis of such evidence not only assists in the determination of restraint usage, but can also provide insight into the pre-impact position of the occupant. However, the multi-faceted restraint systems and advanced materials used in modern vehicles can make the interpretation of vehicle interior damage difficult. This is especially true for impacts of mild or moderate severity, when interior damage may or may not be expected to occur, and the lack of any identifiable damage can be misinterpreted. In this paper, the restraint system damage resulting from a series of sled tests conducted at a range of mild to moderate impact severities with a normally positioned driver under various restraint conditions is discussed. In addition, characteristics of the impact pulses used in the tests are explored relative to the occurrence or non-occurrence of interior damage. The tests were conducted on a 1999 Dodge Ram standard pickup cab with bucket seats, a three-point, continuous, loop type seatbelt, and a complete instrument panel with a lower dash panel. In each test, only a driver dummy was used, and there was a complete, energy absorbing steering wheel and column. Following any significant loading, each of the involved interior structures was replaced. For each type of simulated impact, a number of restraint conditions were used. All combinations of seatbelt use and non-use and airbag deployment and non-deployment were examined. Following the tests, the interior compartment was scrutinized, and witness marks were noted for various interior components.