Abstract
The purpose of this study was to clarify the relation between pedestrian-truck crash impact velocity and the risks of serious injury and fatality to pedestrians. We used truck-pedestrian accident data from the Japanese Institute for Traffic Accident Research and Data Analysis（ITARDA）database. We classified vehicle type into five categories: heavy-duty trucks（gross vehicle weight （GVW）≥11×103kg（11 tons）（t））, medium-duty trucks（5×103kg（5t）≤GVW＜11×103kg（11t））, light-duty trucks（GVW＜5×103kg（5t））, box vans, and sedans. The fatality risk was≤5％ for light-duty trucks, box vans, and sedans at impact velocities≤30km/h and for medium-duty trucks at impact velocities ≤20km/h. In addition, the fatality risk was≤10％ for heavy-duty trucks at impact velocities ≤10km/h. Thus, fatality risk appears strongly associated with vehicle class. The results also revealed that a 10-km/h reduction in impact velocities could mitigate the severity of pedestrian injuries at impact velocities≥30km/h for all five analyzed vehicle types. Therefore, serious injuries and fatalities to pedestrians will be greatly decreased when the collision mitigation system（CMS）developed and deployed throughout the vehicle fleet─including commercial trucks─to reduce impact velocities. The present results indicate that CMS design specifications should be separate between each vehicle type because of the strong dependence of serious-injury and fatality risks on vehicle type.
