The present invention relates to a system (1) and method for autonomous rear impact mitigation in a host vehicle (2) having a brake system (4) and a steering system (5). The relative motion parameters between the host vehicle (2) and a second vehicle (11) behind the host vehicle (2) are established. While the host vehicle (2) has a positive velocity, the brake system (4) of the host vehicle (2) is selectively activated based on the determined relative motion parameters.