Investigating the collected vehicle-pedestrian conflicts by a LIDAR sensor based on a new Post Encroachment Time Threshold (PET) classification at signalized intersections

LIDAR is one of the recent technologies that highlight objects, detects movements and manages object recognition of both non-stationary and stationary objects. LIDAR sensor is capable of recording traffic data including the number of passing vehicles, pedestrians, and bicyclists, the speed of vehicles, and the number of conflicts among different road users. LIDAR sensor collects high-density point clouds at high frequency, and it offers huge potential to capture details that otherwise would not have been possible. Hereupon, as a part of intelligent mobility, the Velodyne LIDAR sensor was installed at Cold Spring Ln – Hillen Rd intersection in Baltimore city to collect real-time traffic data that would be helpful to current road users. The obtained data by the LIDAR sensor was analyzed during the time interval from May 1st to August 31st, 2022. The daily vehicle volumes including passenger cars, buses, trucks, and also vulnerable road users including pedestrians and bicyclists were analyzed. The installed LIDAR sensor at Cold Spring Ln - Hillen Rd intersection records the Post Encroachment Time Threshold (PET) between two cars, vehicle-pedestrians, and car-bicyclists. PET shows the time between the departure of the encroaching vehicle/pedestrian from the conflict point and the arrival of the vehicle/pedestrian with the right-of-way at the conflict point. The frequency of vehicle-pedestrian conflicts and the severity of conflicts were analyzed and the results showed that 848 conflicts occurred during a period of four months. A new methodology for classifying PET values was proposed. Finally, a new risk index was suggested so that it considers the frequency and severity of conflicts, vehicle and pedestrian volumes, and the trajectories of all road users simultaneously. The safety MOE confirmed that safety considerations should be proposed for the western, and southern approaches to the intersection.