Evaluating and Validating a New Pedestrian Exposure to Risk Metric

The ultimate goal of the Pedestrian Exposure to Risk project is to more effectively allocate resources to improve pedestrian safety, based on crash statistics, as well as to more effectively evaluate trends and impacts of safety improvements. In order to accomplish this goal, it is essential to have information not only on the number of pedestrian fatalities but also on the relative exposure of the pedestrians at risk. In the case of calculating meaningful pedestrian crash rates, the numerator (number of pedestrian fatalities) is easy to determine. However, a generally useful denominator has not been as easy to ascertain. Several metrics to evaluate pedestrian exposure to risk have been proposed. Although these previously proposed metrics all have advantages and disadvantages, none has the relevance and generalizability of the denominator used for motor vehicle crashes (million vehicle miles traveled). The purpose of this study was to identify, test, and validate the use of million pedestrian feet traveled as the denominator for pedestrian exposure based on the analogous motor vehicle denominator.