The Rationale and Development of the Offset Deformable Frontal Impact Test Procedure

Accident research has shown that intrusion into the passenger compartment is the major cause of fatal and serious injuries suffered by restrained car occupants in frontal impacts. Current frontal test procedures, which use rigid barriers impacting the full car width, generate high vehicle decelerations and seat belt loads but very low levels of intrusion. In accidents, few serious or fatal injuries result from seat belt loading whereas over two thirds of such injuries, suffered by seat belt wearers, have been shown to be due to contact with intruding structures. The need for some form of asymmetric test has been recognised for some time but more recently it has become clear that the use of rigid barriers is misleading car design. An offset impact test using a deformable barrier face overcomes the problems seen with the rigid barrier whilst also providing asymmetric loading. This test procedure, which has been developed by members of the European Experimental Vehicles Committee (EEVC), has received widespread acceptance for its technical merit. However in Europe, some car manufacturers have managed to press legislators to agree to the adoption of an angled barrier test before adopting the offset deformable test. Lack of experience or validation of the proposed angled barrier test, problems with the Anti-Slide Devices (ASD) employed and questions over its effectiveness in improving car design have caused many to question this decision. This paper gives the background to the development of the offset deformable test procedure, explains why an asymmetric deformable test is required and discusses some of the technical problems identified with the 30° angled barrier test with ASD.