The Transport and Road Research Laboratory (TRRL), acting on behalf of the Vehicle Standards and Engineering (VSE) of the Department of Transport (DTp), commissioned the Accident Research Unit (ARU) at Loughborough University to analyse a sample of police reports of fatal accidents. These accidents concern car occupants who were killed following a collision with the front of a heavy goods vehicle (HGV) in 1988. The objective was principally to estimate the numbers who might have survived had underrun guards been fitted to the trucks. The data was coded by the ARU according to a protocol developed by the ARU in conjunction with TRRL and DTp. This data coding and analysis involved a comparison with a TRRL test collision performed using underrun guards fitted with a ground clearance between 300-400mm. For each fatality the judgement was made as to whether he or she would have survived: given restraint use but no underrun guard; given an underrun guard was fitted but restraints were not worn; and given restraints were worn and underrun guards fitted. These judgements were based upon the damage pattern of the car and the HGV, the location, nature, severity and likely cause of the injuries, the speed estimates, comparisons with test impacts and the investigators experience gained from inspecting many fatal and non-fatal car-HGV collisions. The results for each category of restraint use were combined for the complete sample. Those whose restraint use was unknown were apportioned to restraint use groups according to their seating position and the restraint use rates of the remainder of the sample. A weighting factor of 2.5 was derived to relate the sample analysed to the national estimates for Great Britain. The resulting estimates of fatality reductions in the sample and in Great Britain are presented in this report. Appendices provide information on: (A) the data coding methodology; (B) the benefits of underrun guard fitment and restraint use-coding techniques; and (C) the supplementary analysis.

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