In a collision accident, whiplash-injury can be estimated indirectly using the effective collision speed. The effective collision speed due to the collision depends on the speed, posture, and rigidity of the vehicle. In this study, the rebound coefficient was derived using the results of 214 rear-end collision experiment. When the derived rebound coefficient was analyzed, the characteristics of the rebound coefficient according to offset and intrusion could be confirmed. In addition, the reliability of the simulation model was confirmed by comparing the experiment and the simulation.