Abstract
In order to evaluate the effect of head restraint systems, a mathematical model was assumed to simulate occupant movements during rear-end collisions. By comparing the results of the mathematical simulation with the experimental data, a fairly good agreement was obtained, and the assumption of the mathematical model employed was found to be reasonable. The effects of each element such as seat back, seat back cushion, head restraint, seat belt, and so on were investigated by means of this mathematical simulation. As a result, it can be concluded that the installation of a head restraint system is important in order to reduce the injury of occupants and that the dimensions of various elements are fairly flexible due to human tolerance.