The Influence of Gait Stance and Vehicle Type on Pedestrian Kinematics and Injury Risk

Abstract Pedestrians are one of the most vulnerable road users. In 2018 the USA reported the highest number of pedestrian fatalities number in nearly three decades. Government safety agencies and car manufacturers have started paying greater attention towards pedestrian protection. The pre-impact conditions of Car-to-Pedestrian Collisions (CPC) varies significantly in terms of the characteristics of vehicles (e.g. front-end geometry, stiffness, etc.) and pedestrians (e.g. anthropometry, posture, etc.). The influence of vehicle type and pedestrian gait has not been analyzed. The purpose of this study was to numerically investigate the changes in pedestrian kinematics and injuries across various gait postures and two different car types. Five finite element (FE) human body models, representing 50th percentile male in gait cycle, were developed and used to perform CPC simulations with two generic vehicle FE models representing a family car (FCR), and a sport utility vehicle (SUV). In the impacts with the high-profile vehicle (SUV), the pedestrian models usually slide above the bonnet leading edge and report shorter wrap around distances (WAD) than in low-profile vehicle (FCR) impacts. The pedestrian postures influenced the post-impact rotation of the pedestrian and consequently, the impacted head region. The pedestrian posture also influenced the risk of injuries in the lower extremities. Higher risk of bone fractures was observed in the stance phase posture compared to the swing phase. The findings of this study should be taken into consideration when examining pedestrian protection protocols. In addition, the results of this study can be used to improve the design of active safety systems used to protect pedestrians in collisions.