Correlation between pedestrian injury severity in real-life crashes and Euro NCAP pedestrian test results

In Germany the number of casualties in passenger car to pedestrian crashes has been reduced by a considerable amount of 40% as regards fatalities and 25% with regard to seriously injured pedestrians since the year 2001. Similar trends can be seen in other European countries. The reasons for that positive development are still under investigation. As infrastructural or behavioral changes do in general take a longer time to be effective in real world, explanations related to improved active and passive safety of passenger vehicles can be more relevant in providing answers for this trend. The effect of passive pedestrian protection – specified by the Euro NCAP pedestrian test result – is of particular interest and has already been analyzed by several authors. However, the number of vehicles with some valid Euro NCAP pedestrian score (post 2002 rating) was quite limited in most of those studies. To overcome this problem of small datasets German National Accident Records have been taken to investigate a similar objective but now based on a much bigger dataset. The paper uses German National Accident Records from the years 2009 to 2011. In total 65.140 records of pedestrian to passenger car crashes have been available. Considering crash parameters like accident location (rural / urban areas) etc., 27.143 of those crashes have been classified to be relevant for the analysis of passive pedestrian safety. In those 27.143 records 7.576 Euro NCAP rated vehicles (post 2002 rating) have been identified. In addition it was possible to identify vehicles which comply with pedestrian protection legislation (2003/102/EG) where phase 1 came into force in October 2005. A significant correlation between Euro NCAP pedestrian score and injury outcome in real-life car to pedestrian crashes was found. Comparing a vehicle scoring 5 points and a vehicle scoring 22 points, pedestrians’ conditional probability of getting fatally injured is reduced by 35% (from 0.58% to 0.37%) for the later one. At the same time the probability of serious injuries can be reduced by 16% (from 27.4% to 22.9%). No significant injury reducing effect, associated with the introduction of pedestrian protection legislation (phase 1) was detected. Considerable effects have also been identified comparing diesel and gasoline cars. Higher engine displacements are associated with a lower injury risk for pedestrians. The most relevant parameter has been “time of accident”, whereas pedestrians face a more than 2 times higher probability to be fatally injured during night and darkness as compared to daytime conditions. INTRODUCTION In Germany the number of fatal and severe pedestrian to passenger car crashes decreased by a considerable amount in the first decade of 2000. Comparing police recorded passenger car to pedestrian accident records from the years 2001 to 2003 with data records from 2009 to 2011, the number of fatally injured pedestrians dropped by 40%. The number of seriously injured pedestrians decreased by 25% and the number of slightly injured pedestrians was reduced by 11% (see Figure 1). The reasons for that positive trend are still under investigation. As infrastructural or behavioral changes do in general take a longer time to be effective in real world, explanations related to improved active and passive safety of passenger vehicles can be more relevant in providing explanations to this appreciable trend. Figure 1. Reduction of pedestrian casualties in first decade of 2000. The effect of passive safety can be extracted by looking at the proportion of killed or seriously injured (KSI) pedestrians. In the years 2001 to 2003 the share of KSI pedestrians was 31.3% and has been reduced to 27.8% for the data records from the years 2009 to 2011. This means that the probability of pedestrians in getting seriously injured or killed in a crash with a passenger car was reduced by 11% (assuming that the share of underreported cases did not change).