In 1988 NHTSA published an Advanced Notice Of Proposed Rulemaking that described a test procedure and performance requirements to improve the protection available to car occupants in side impacts. The test configuration involves a mobile barrier with a mass of the median value of US cars and a stiffness similar to that of light trucks. This impacts the passenger compartment of the vehicle in a crabbed motion with an approach speed of 54 kph. The tested vehicle contains instrumented side impact dummies seated unrestrained in the front and rear struck side positions. Maximum levels of the Thoracic Trauma Index (TTI), which is acceleration based, and pelvic acceleration are imposed to minimise torso and pelvis injury. The corresponding European Experimental Vehicle Committee (EEVC) proposals employ a softer mobile barrier, typical of the "average" European car. The mass is lower and is based on the mass of production vehicles weighted by registration volume. The barrier strikes the passenger compartment of the tested car in a perpendicular configuration at an approach speed of 50 kph. A restrained, instrumented Eurosid dummy is seated in the front struck side seat. Maximum limits of the dummy transducer measurements are set to restrict head, chest, abdomen and pelvis injuries. Both tests attempt to assess the severity of the impact perceived by a struck side occupant and these are viewed as the priority for improving side impact protection. A part of the development of any standard should be an appraisal of its likely effectiveness. Such an appraisal may fall into two stages; first an estimate of the numbers of car occupants who are in impacts that are similar to the test procedure, and second an estimate of the reduction of the levels of the injuries of those occupants. This analysis addresses the first stage of an appraisal and examines the similarity of the two test conditions to the data describing UK accidents. (A) For the covering abstract of the conference, see IRRD 837684.
Abstract