LiDAR-Based Vehicle–Pedestrian Interaction Study on Midblock Crossing Using Trajectory-Based Modified Post-Encroachment Time

Abstract

Understanding pedestrian road crossing behavior is crucial in the interests of pedestrian traffic safety. The interaction between pedestrians and approaching vehicles at midblock road crossings is a complex process. The high degree of vehicle heterogeneity and poor lane discipline in low- and middle-income countries further adds to its complexity. Moreover, because of the lack of proper pedestrian facilities, pedestrian crossing behavior is quite different in low- and middle-income countries. It is necessary to have high-resolution data to study pedestrian crossing behavior. At midblock, pedestrians do not always take the shortest route while crossing the road and cross diagonally, moving toward or away from the approaching vehicle. The risk indicator of crossing changes based on the pedestrian path chosen. This study was based on studying vehicle–pedestrian interaction at midblock locations using light detection and ranging (LiDAR) data. This study considered a trajectory-based pedestrian modified post-encroachment time (PET) to account for the various possible pedestrian crossing trajectories. Suitable algorithms were developed to identify and track vehicles and pedestrians from the LiDAR point cloud data. The results showed the trajectory-based pedestrian modified PET to perform better than the traditional PET. The risk-taking appetite of pedestrians was also observed to be high when motorbikes were the approaching vehicle. This study showed the motorbike–pedestrian conflicts to be riskier as compared with car–pedestrian conflicts. The results obtained from this study would be helpful to practitioners in investing higher priority to proper pedestrian-related road infrastructure.