Srinivasan Sundararajan

THE BIOMECHANICAL ASPECTS OF PEDESTRIAN PROTECTION

In this paper, a biomechanical basis for pedestrian protection is presented based on reviews of epidemiological and biomechanical studies conducted over the last three decades. Epidemiological studies reveal the nature and cause of pedestrian crashes and injuries sustained in the field. The various factors that influence pedestrian crashes and fatalities such as pedestrian demographics, time and location of crash, type of vehicles involved and their design characteristics, impact speeds, and nature and severity of injuries sustained are covered in the epidemiology section. The biomechanical studies identify the injury mechanisms and the biomechanical tolerances. Several biomechanical studies that attempt to identify the injury mechanisms and quantify the tolerances are critically reviewed in this paper, and the existing gaps in literature are identified. Further, the three primary injury mechanisms for pedestrian lower extremity injuries are highlighted, and an injury mechanism for depressed tibial fracture is hypothesised. The effect of exterior vehicle parameters such as bumper height, bumper stiffness, hood length, hood stiffness, bumper lead angle on the nature and severity of injuries sustained are also discussed. The biomechanical injury criteria and tolerance values in a proposed draft ECE pedestrian regulation are also presented. Finally, conclusions are drawn based on the epidemiological and biomechanical studies, which lead to a proposal for future work.