Methods, upper limit and reason for reducing pedestrian ground contact injury by controlling vehicle braking

Abstract

In order to access the maximum benefits of controlled vehicle braking in reducing ground related injury, based on a basic simulation test sample, which include 24 simulations with three velocities, four pedestrian sizes and two pedestrian gaits, 10176 simulations were conducted by Madymo. After comparative study, we found that the vehicle caused injury will not increase if the vehicle braking is starting to reduce at the time the pedestrian head first contact the vehicle and the ground related WIC/HIC can be maximally reduced 88.9% and 75.6% respectively by controlling the vehicle braking efficiently. Through a further analysis we found that the optimal time at which the vehicle was to fully brake again (t2) is not hard to obtain because the optimal t2 is not an isolated point and hence it is easy to obtain a simple controlling method for a specific car shape but it may be impossible to find one way to control the braking of vehicles with different shapes. And the possible reason that the ground related injury can be reduced is the change of the landing mechanism. Not all ground related injury can be reduced because in some fully braked cases the WIC/HIC is already equal or close to 0; and two danger situations for controlling the vehicle braking were found, which are the pedestrian fall to the ground from the vehicle side and the controlled vehicle cannot contact the pedestrian’s main body in the controlling braking process. Research results will enhance our confidence.