Rethinking Safety in Numbers: Are Intersections with More Crossing Pedestrians Really Safer?

Abstract

Objective: To advance the interpretation of safety in numbers by addressing the following three questions. How can the safety of pedestrians be measured, the safety of individual pedestrians or the safety of road facilities? Are intersections with more crossing pedestrians really safer? Would encouraging walking be an effective countermeasure to improve the safety of pedestrians? Methods: We selected 288 signalized intersections with 1003 pedestrian crashes that occurred in Hong Kong during 2010-2012. A Bayesian Poisson lognormal model was developed, based on which two common indicators, the expected crash rate per million crossing pedestrians and the expected excess crash frequency, were calculated. The ranking results of these two indicators for the selected intersections were then compared. Results: We confirmed the significantly positive relationship between pedestrian volume and pedestrian crashes, with a coefficient estimated at 0.21. Although people at intersections with higher pedestrian volumes generally experienced a relatively lower crash risk, these intersections may still show substantial potential for crash reduction. Conclusions:Conclusions on safety in numbers using a cross-sectional dataset should be reached with great caution. The safety of individual pedestrians can be measured based on crash risk, whereas the safety of road facilities for pedestrians should be determined by the environmental hazards of walking. Intersections with more crossing pedestrians do not always exhibit favorable safety performance. Relative to increasing the number of people walking to improve the safety of pedestrians, safety strategies should focus on reducing environmental hazards and removing barriers to walking.