Vehicle Crashworthiness and Aggressivity Ratings and Crashworthiness by Year of Vehicle Manufacture
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VEHICLE CRASHWORTHINESS AND AGGRESSIVITY RATINGS AND CRASHWORTHINESS BY YEAR OF VEHICLE MANUFACTURE: VICTORIA AND NSW CRASHES DURING 1987-2002 QUEENSLAND, WESTERN AUSTRALIA AND NEW ZEALAND CRASHES DURING 1991-2002 by Stuart Newstead Max Cameron and Linda Watson Report No. 222 June 2004 Project Sponsored By ii MONASH UNIVERSITY ACCIDENT RESEARCH CENTRE MONASH UNIVERSITY ACCIDENT RESEARCH CENTRE REPORT DOCUMENTATION PAGE Report No. Report Date ISBN Pages 222 June 2004 0 7326 1732 4 69 + Appendices Title and sub-title: Vehicle Crashworthiness and Aggressivity Ratings and Crashworthiness by Year of Vehicle Manufacture: Victoria and NSW Crashes During 1987-2002, Queensland, Western Australia and New Zealand Crashes During 1991- 2002 Author(s) Type of Report & Period Covered Newstead, S.V., Cameron, M.H. and Watson, L.M. Summary Report, 1982-2002 Sponsoring Organisations - This project was funded as contract research by the following organisations: Road Traffic Authority of NSW, Royal Automobile Club of Victoria Ltd, NRMA Ltd, VicRoads, Royal Automobile Club of Western Australia Ltd, Transport Accident Commission and Land Transport Safety Authority New Zealand and by a grant from the Australian Transport Safety Bureau Abstract: Crashworthiness ratings measure the relative safety of vehicles in preventing severe injury to their own drivers in crashes whilst aggressivity ratings measure the serious injury risk vehicles pose to drivers of other vehicles with which they collide. Crashworthiness and aggressivity ratings for 1982-2002 model vehicles were developed based on data on crashes in Victoria and New South Wales during 1987-2002 and in Queensland, Western Australia and New Zealand during 1991- 2002. This study represents the first time New Zealand data has been included in a full update of the ratings. Crashworthiness and aggressivity were measured by a combination of injury severity (of injured drivers) and injury risk (of drivers involved in crashes). The ratings were adjusted for the driver sex and age, the speed limit at the crash location, the number of vehicles involved, the state in which the crash occurred and the year in which the crash occurred. These factors were strongly related to injury risk and/or severity for both aggressivity and crashworthiness. Both ratings estimate, with the appropriate focus, the risk of a driver being killed or admitted to hospital when involved in a tow-away crash, to a degree of accuracy represented by the confidence limits of the rating in each case. The crashworthiness estimates and their associated confidence limits were obtained for 255 vehicle models and were sufficiently sensitive that they were able to identify 128 models of passenger cars, four-wheel drive vehicles, passenger vans and light commercial vehicles that have superior or inferior crashworthiness characteristics compared with the average vehicle. Aggressivity rating estimates and their associated confidence limits were obtained for 202 vehicle models and were sufficiently sensitive that they were able to identify 80 models of passenger cars, four-wheel drive vehicles, passenger vans and light commercial vehicles that have superior or inferior aggressivity characteristics compared with the average vehicle. Also investigated was the relationship between vehicle crashworthiness and the year of manufacture of Australian passenger and light commercial vehicles manufactured from 1964 to 2002. Trends were examined by year of manufacture both for the fleet as a whole and by market group for vehicles manufactured from 1982 to 2002. The results of this report are based on a number of assumptions and warrant a number of qualifications that should be noted. Key Words: (IRRD except when marked*) Injury, Vehicle Occupant, Collision, Passenger Car Unit, Passive Safety System, Statistics Disclaimer: This Report is produced for the purposes of providing information concerning the safety of vehicles involved in crashes. It is based upon information provided to the Monash University Accident Research Centre by VicRoads, the Transport Accident Commission, the New South Wales Roads and Traffic Authority, NRMA Ltd, Queensland Transport, the Western Australian Department of Main Roads and Land Transport Safety Authority in New Zealand. Any republication of the findings of the Report whether by way of summary or reproduction of the tables or otherwise is prohibited unless prior written consent is obtained from the Monash University Accident Research Centre and any conditions attached to that consent are satisfied. A brochure based on this report is available from the sponsoring organisations and may be freely quoted. Reproduction of this page is authorised Monash University Accident Research Centre Building 70, Monash University Victoria 3800, Australia. Telephone: +61 3 9905 4371, Fax: +61 3 9905 4363 VEHICLE CRASHWORTHINESS AND AGGRESSIVITY RATINGS: 1987 TO 2002 DATA iii EXECUTIVE SUMMARY This report describes the development of further updated vehicle safety ratings for 1982- 2002 model vehicles. The ratings produced cover both vehicle crashworthiness and aggressivity. Crashworthiness ratings measure the relative safety of vehicles in preventing severe injury to their own drivers in crashes whilst aggressivity ratings measure the serious injury risk vehicles pose to drivers of other vehicles with which they collide. Both measures are estimated from data on real crashes reported to police. The update is based on crash data from Victoria and New South Wales during 1987-2002 and from Queensland, Western Australia and New Zealand during 1991-2002. This is the first time data from New Zealand has been included in a full update of the ratings. The rating of vehicle crashworthiness through analysis of real crash data, as carried out here, and through crash tests carried out by consumer groups such as the Australian New Car Assessment Program has encouraged manufacturers to improve vehicle safety. Both crashworthiness and aggressivity were measured by a combination of injury severity (of injured drivers) and injury risk (of drivers involved in crashes). Crashworthiness injury severity was based on 251,269 drivers injured in crashes in Victoria during 1987-2002, in New South Wales during 1987-1998 and in Queensland, Western Australia and New Zealand during 1991-2002. Crashworthiness injury risk was based on 1,070,369 drivers involved in crashes in New South Wales during 1987-2002 and Western Australia and Queensland during 1991-2002 where a vehicle was towed away. Aggressivity injury risk was based on 581,073 drivers involved in crashes between two vehicles in New South Wales and Queensland and Western Australia where a vehicle was towed away. Aggressivity injury severity was based on 134,727 drivers injured in two-car crashes in Victoria during 1987-2002, in New South Wales during 1987-1998 and in Queensland, Western Australia and New Zealand during 1991-2002. The crashworthiness and aggressivity ratings were adjusted for the driver sex and age, the speed limit at the crash location, the year in which the crash occurred and the jurisdiction in which the crash occurred. Crashworthiness ratings were also adjusted for the number of vehicles involved in the crash. These factors were found to be strongly associated with injury risk and injury severity. Adjustments were made with the aim of measuring the effects of vehicle factors alone, uncontaminated by other factors available in the data that affected crash severity and injury susceptibility. The crashworthiness ratings estimate the risk of a driver of the focus vehicle being killed or admitted to hospital when involved in a tow-away crash, to a degree of accuracy represented by the confidence limits of the rating in each case. Statistically reliable crashworthiness ratings were calculated for 255 individual vehicle models manufactured between the years 1982-2002. The estimates and their associated confidence limits were sufficiently sensitive that they were able to identify 128 models of passenger cars, four- wheel drive vehicles, passenger vans and light commercial vehicles that have superior or inferior crashworthiness characteristics compared with the average crashworthiness across all vehicles in the data. Compared to previous ratings updates that have classified vehicle models into one of 8 market groups, this study has defined 13 market groups for presentation of the ratings with average crashworthiness of vehicles in each market group estimated. iv MONASH UNIVERSITY ACCIDENT RESEARCH CENTRE Aggressivity ratings were calculated for 202 models of Australian and New Zealand passenger vehicles manufactured between the years 1982-2002. Aggressivity ratings estimate the risk of a driver of a vehicle impacting with the focus vehicle model being killed or admitted to hospital when involved in a tow-away crash. The degree of accuracy of the aggressivity ratings is represented by the confidence limits of the rating in each case. The estimates and their associated confidence limits were sufficiently sensitive that they were able to identify 80 vehicle models that have superior or inferior aggressivity characteristics compared with the average aggressivity across all vehicle models in the data. Average aggressivity for vehicles in each of the 13 defined market groups was also estimated. Estimated vehicle aggressivity towards drivers of other vehicles was found to have little or no relationship with ratings of vehicle crashworthiness, demonstrating the independence of the two complementary measures.