Vehicle occupant protection : four-wheel-drives, utilities and vans.

Although the number of 4WDs, utilities (not passenger car derivatives) and forward control vans in Australia is increasing, very little is known about the occupant protection they offer in real world crashes. Furthermore, these vehicles are not subject to the full range of design rules applicable to passenger cars and their derivatives. The aim of this study was to examine the extent and patterns of injuries sustained by occupants of 4WDs, utilities and vans in crashes where the vehicle was classified as "written-off", and to ascertain the need for more stringent regulations governing this group of vehicles. The study involved three main stages: (1) a review of the international literature covering the crashes and crash performance associated with these vehicles (or their closest overseas equivalents); (2) analysis of two mass databases covering casualty crashes in NSW and fatal crashes throughout Australia where vehicle type was coded; and (3) a detailed investigation of 144 "write-off" crashes involving roughly equal numbers of post-1985 4WDs, utilities and vans. The majority of crashes were found to be frontal ones, although rollovers were over-represented (mainly for 4WDs) by comparison with the crashed passenger car file. The crashes sampled in this study were of low severity compared to the sample of passenger car crashes, as reflected by relatively low impact velocities (modal Delta-V of 18-24 km/h), few instances of entrapment or ejection, and low levels of injury (84% either uninjured or minor injury not requiring hospitalisation). Minor (AIS<2) injuries to the upper limbs through contact with seat belts, steering wheels and instrument panels were most common, although whiplash injuries were also prevalent (approximately one third of all drivers). Injuries to the upper and lower leg through contact with the instrument panel and floor were over-represented among van drivers, consistent with the preponderance of frontal crashes and the reduced crumple space in these vehicles. Head and spinal injuries caused by roof contacts were slightly over-represented among drivers of 4WDs and utilities, consistent with their over-involvement in rollover crashes. Countermeasures relating primarily to improved steering assembly, restraint systems and instrument panel construction are discussed, and recommendations are made for an extension of the study to include more hospitalised cases. (A)