Involving physicians in road traffic safety requires the interaction of medically trained professionals, educationalists, legislators, mass media, traffic enforcement personnel and the general community on an individual and a collective basis. Physicians should appreciate the important role they must play in the prevention of traffic injury. The local medical practitioner is an essential member of any total community commitment dedicated to eliminating this major epidemic affecting all mobile modern societies. The physician needs to acquaint himself with the basic techniques of accident analysis and reconstruction and the application of this analysis to local programmes of crash and injury prevention. His knowledge of the problem will take him beyond the basic physics of human occupant kinematics and human tissue injury patterns to the interaction between the moving vehicle and its environment, THE ROADWAY AND THE ROADSIDE