Prediction of pedestrian's head collision position by analysis of 56 accidents and mathematical model simulation

Abstract

 Generally, in the analysis of the accident between the car and the pedestrian, an index called Wrap Around Distance (WAD) is used to quantify to the positional relationship of the pedestrian's head because the pedestrian falls so as to wrap around the front shape of the car. There are a few reports in Japan that the relationship between the WAD ratio and the impact speed was expressed by linear regression based on the assumption that the position where the pedestrianʼs head collides moves to the rear of the car as the impact speed of the car increases. However, the coefficient of determination in the linear regression is so small that the behavior of the pedestrianʼs head during the collision was not properly described. It is inappropriate for the accidental reconstruction to apply WAD in estimating the impact speed of the car.

 We created the mathematical model that predicted the positional relationship between the pedestrianʼs head and the car analyzing 56 accidents. Our model described in detail the behavior of the pedestrianʼs head by considering both the behavior of the pedestrian during the collision and the deformation of the car. As a result, our model indicated that the behavior of the pedestrianʼs head changed the distance from the height of the front edge of the hood to the pedestrianʼs center of gravity, and the position restricted the upper limit by visualizing the simulation results for 7 data.