DEVELOPMENTS IN CAR CRASH SAFETY AND COMPARISONS BETWEEN RESULTS FROM EURO NCAP TESTS AND REAL-WORLD CRASHES

摘要

Developments in car crash safety is preferably demonstrated by analyzing results from real-world crashes. Also results from crash tests can be used to show improvements in crash performance. Previous research has shown a positive development regarding safety performance. Studies from the early 2000 have shown that the European New Car Assessment Programme (Euro NCAP) consumer tests seem to predict the outcome in real-world crashes, although they consider only a part of all accident scenarios. In 2009 Euro NCAP added rear-end crash tests to the test protocol and since 2012 Euro NCAP has gradually further revised the rating protocol. It is therefore important to study developments in crash safety, and to evaluate how Euro NCAP test results correlate with real-world performance. This study aimed to show developments in car crash safety in cars launched since the 1980s based on real-world data, and to present how Euro NCAP crash test results predict the outcome in real-world crashes. Two-car crashes reported by the police (n=202 360) and occupant injuries reported by emergency care centers (n=57 863) to the Swedish Traffic Accident Data Acquisition database (STRADA) were analyzed. The cars were categorized in 5-year periods, according to the year of introduction. Developments were studied in terms of risk of any injury, risk of serious injury, risk of fatality, and risk of permanent medical impairment (PMI). Correlations with Euro NCAP test results were evaluated based on star levels for all categories of injury severity. It was found that vehicle crashworthiness has improved steadily over the years studied. The proportion of serious injuries was found to be reduced, as well as the injury risk for all injury severities studied. In a comparison of car models launched 1980-1984 with those launched 2015-2018 the proportion of AIS 3+ injuries was 67% lower. Furthermore, the risk for serious and fatal injury was 58% (+/-17%) lower, the risk for fatal injury was 88% (+/-57%) lower, and the risk for PMI was 73% (+/-14%) lower. It was also shown that Euro NCAP crash test ratings mirror real world injury outcomes for all injury severities studied. Comparing 5-star with 2-star rated cars, the proportion of AIS 3+ injuries was 34% lower. Furthermore, the risk for serious and fatal injury was 22% (+/-4%) lower, the risk for fatal injury was 40% (+/-16%) lower, and the risk for PMI was 42% (+/-4%) lower. Large improvement in crash safety was found, especially regarding the risk for fatal injuries and injuries leading to PMI. Euro NCAP star ratings were found to well mirror the risk for fatal injuries and injuries leading to PMI. Consumer crash tests play an important role for the development in car safety. It is however important to continuously study how well these consumer tests predict the outcome in real-world crashes. Especially considering rating systems that reward the overall safety of a vehicle, such as the Euro NCAP.