Mathematical Simulations of Real - World Pedestrian - Vehicle Collisions

INTRODUCTION Pedestrian-vehicle crashes result in a substantial number of pedestrian fatalities and injuries worldwide. Computer models are powerful tools in understanding how the severity of injuries could have been reduced in the crash. Pedestrian real-world cases serve as an important source of information to evaluate the dynamic performance of pedestrian models and their ability to reconstruct injury-causing events. Road crashes result in a substantial number of pedestrian fatalities and injuries worldwide. Statistics from 35 European countries have shown that pedestrian fatalities represented on average 25% of road users killed throughout Europe (ECMT, 2003). In Japan, pedestrian fatalities accounted for 28% of the road toll (ECMT, 2003), while in Australia approximately 16% of road fatalities were pedestrians (ATSB, 2003). Pedestrian fatalities as a proportion of road fatalities were estimated at 13% in the USA and were as high as 40-50% of the annual road toll in India and Thailand (Mohan and Tiwari, 2000). Head injuries are the most common cause of pedestrian fatalities. Injuries to the chest, spine, abdomen and the lower extremities are also commonly sustained (Anderson and McLean, 2001, Fildes et al., 2004). The objective of this study was to evaluate the ability of a mathematical pedestrian model to assess the severity of an impact using real-world data. The dynamic performance of the pedestrian model was evaluated by the reconstruction of six real-world pedestrian collisions, which occurred during 19952003 in the surroundings of Hanover, Germany. The impact severities were 32-59km/h. Each case contained information about the pre-crash, crash, and post-crash events. This information included hospital reports and detailed description of damages to the vehicle, pedestrian injuries, and the crash environment collected at the scene. The evaluation focused on head injuries since these are the most common cause of severe injuries and fatalities of pedestrians involved in passenger vehicle-pedestrian crashes. Computer simulations provide a powerful tool for studying the loading to the pedestrian in a crash. For the study of overall human kinematics in a crash, computer models based on rigid bodies connected to each other by joints are time efficient. The dynamic and kinematic response of computer models is validated towards biological test results. However, it is important to include evaluation towards realworld cases as part of this process in order to determine the models ability to assess the impact severity in a wide range of scenarios. The results showed that the model produced injury measures and readings of the magnitude expected for the highest severity head injuries sustained by the pedestrian in the reconstructed case. Furthermore it highlights the usability of mathematical pedestrian models in evaluating the severity of a vehiclepedestrian collision. The aim of this study was to evaluate the ability of a mathematical pedestrian model to assess the severity of an impact by reconstruction of six real-world passenger vehicle-pedestrian collisions.