The introduction of automatic emergency braking changes the distribution of impact severity thus the resulting injury risk. In the calculation of the possible safety impact, risk functions must be used. These functions can be derived in different ways. In this paper, matched pair techniques have been used to study if the power models developed by Nilsson can be used.

By applying the risk functions on theoretical changes of impact speed as a result of pre impact braking, the possible effectiveness on fatal and serious injuries can be estimated. It was found, that such braking can offer major benefits. A reduction of speed before impact with 10 % can reduce fatal injuries in car crashes with approximately 30 %.