This paperreviews the information available on the biomechanics of trauma to riders of two-wheeled machines and to pedestrians. Data come from hospital studies, field accident investigations and experimental work. A general description of the trauma received by these groups of road users is given in terms of the frequency and severity of injuries to the main anatomical regions of the body.

Information on the circumstances of collisions is summarised as far as is known, in relation to specific sources of injury, the relative importance of vehicular and ground contacts and the influence of speed on these circumstances. The paper concludes by emphasizing the importance of improved vehicle design in minimising injuries to these classes of road user, an area which has so far received relatively little attention.