Development of head injury risk functions based on real-world accident reconstruction

The objective of this study is to assess head injury risks of adult pedestrians using computer reconstructions of the accidents. For this purpose, accident reconstructions were developed based on the real-world pedestrian accidents. The impact conditions, which were obtained from the previous study [Y. Peng, C. Deck, J.K. Yang, D. Otte, and R. Willinger, A study of adult pedestrian head impact conditions and injury risks in passenger car collisions based on real world accident data, Traffic Inj. Prev., doi: 10.1080/15389588.2012.733841] including head impact velocity, head position and head orientation, were defined as initial loading conditions in a simulation of the head striking to a windscreen by using a finite element (FE) Hybrid III head model. Logistic regression models were developed to study brain injury risk with respect to injury related variables: the head linear acceleration, HIC value, skull fracture correlate (SFC), resultant angular acceleration and head impact power (HIP). The results from Hybrid III head impact simulations indicated that the predicted head linear acceleration, HIC value, resultant angular acceleration and HIP for 50% probability of AIS 2+ and AIS 3+head injury risk are 116g, 825, 11368 rad/s(2), 37 kW and 162g, 1442, 18775 rad/s(2), 68 kW, respectively, and the predicted values of 50% probability of skull fracture is 135g. The knowledge from this study could be a prerequisite for developing guidelines to improve pedestrian safety.