A correlation was developed which allows an estimate of the coefficient of restitution for vehicle-to-vehicle bumper impacts to be made. Published restitution data for vehicles equipped with isolator, rigid, and foam-core bumpers were analyzed. The restitution data were found to correlate reasonably well with the closing velocity and almost as well with the target vehicle velocity change. On the other hand, the data scatter for vehicle-to-barrier impacts was so great that a correlation was not attempted. In addition, a number of vehicle-to-vehicle collisions were “simulated” using vehicle-to-barrier restitution data as input to Howard, et al's equation which was then used to calculate the vehicle-to-vehicle restitution. It was thought that vehicle-to-vehicle restitution determined in this manner would also correlate with closing velocity, but the correlation was weak.