Pedestrian State Analysis Based On Accident Reconstruction In Pedestrian-Vehicle Collision

The number of pedestrian casualties has been high because of large proportion of mixed traffic in China and low safety awareness among driver and pedestrians. Thus, the study of pedestrian protection and injury mechanism in road traffic accident has important practical significance to reduce pedestrian casualties. Accident reconstruction simulation software is one of the most widely used, fast and effective methods. At present, there are many researches on the effect of vehicle motion states to accident reconstruction simulation results. However, the influence of pedestrian motion states to the reconstruction results are rarely. Therefore, Pedestrian motion states will be the focus of this study.In order to study and verify the rules of the influence of pedestrians initial state to the accident reconstruction results in vehicle-pedestrian accident, further improve the accident reconstruction simulation precision and speed, vehicle-pedestrian accident characteristics in China were first to be analyzed and summarized with 186 real vehicle-pedestrian collisions which were collected by National Automobile Accident In-Depth Investigation System from 2013 to 2015. Secondly, the influence of pedestrian factors to simulation results was qualitatively validated through real accident case. Finally, the collision simulation models were set up by using the PC-CRASH accident reconstruction software on the basis of the actual statistical data. Control variable method is used to design the simulation test.Through the analysis of a large number of simulation results at a certain vehicle speed, the nine influence laws of the pedestrian gait to the collision damage degree were got. Firstly, the influence degree from large to small is left knee, left lower leg, head, thorax, hip and left femur. Secondly, different head-hood impact acceleration is mainly caused by the relative position of pedestrian lower extremity and the head-hood impact acceleration is max at the 50% pedestrian gait. Thirdly, the different thorax-hood impact acceleration is mainly caused by different support legs and the Thorax-hood impact acceleration is max at the 30% pedestrian gait. Fourth, hip side force peak is mainly determined by the degree of pedestrian leg separately. The more open of legs, the greater the lateral force peak and has nothing to do with whether be bumped legs support legs. Fifth, lower knocked leg and knee's lateral force peak is related to the pedestrian leg is together or separately, has nothing to do with which is the supporting leg. Sixth, the human body injury reduced gradually with the increase of pedestrian speed. Seventh, pedestrian-to ground head collision acceleration is almost directly proportional to the maximum thrown height and biggest at the 60% gait, which mainly caused by the body rotation Angle around the Z axis. Eighth, the influence of gait on the transverse thrown distance is greater than that of the longitudinal distance and the total distance. Finally, the higher the pedestrian height, the smaller the pedestrian's longitudinal thrown distance. The heavier the weight, the heavier the injury, but the increasing range is not obvious.The conclusions of the study can be used for the analysis of accident cause and the study of accident reconstruction.