An initial study into actual car to car collisions has been performed. The study provides insights into the factors associated with physical complaints in real collisions and identifies those areas requiring greater detail.Data compiled from seventy-two, real world, rear automobile collisions shows that a gap exists between current testing and modeling and the realities of a typical rear impact. Analysis of the data indicates that among the most significant factors associated with physical complaints, in a rear impact, is an occupant’s reported awareness of the impending collision. Awareness of an imminent impact allows an occupant in a struck vehicle to exercise sufficient muscle control to prevent flexion/ extension injuries, of the neck, in many collisions. Other factors identified include gender, occupant position, preexisting injuries, seat belt usage, seat back failure and impact orientation. Finally, the data in the study reveals that the potential for significant head and brain injuries exists in pickups, and even large trucks, struck from the rear.Analysis of the data suggests areas that may benefit from more detailed analysis. Among these are the specifics of the injuries/complaints, locations of previous injuries and occupant position.Another contributing factor in preventing flexion/extension injuries of the neck is seat back failure. In those cases where the seat back failed, even slightly, flexion and hyperextension complaints in the neck tended to be less severe. This was found to be true even if the impact was a surprise and at high velocity. The potential may exist to modify current seat design to provide for energy absorption, thereby reducing flexion/extension injuries of the neck.