Assessing the Impact of Intersection Geometry and Driver Eye Position on A-Pillar-Induced Pedestrian Occlusion during Left Turns

Left-turn maneuvers are among the most hazardous intersection movements due to conflicts with oncoming vehicles and crossing pedestrians. Existing traffic standards rely mainly on vehicle volumes and collision history, overlooking how intersection geometry and driver seating position affect pedestrian visibility. Without protected left-turn phases, pedestrians remain especially vulnerable where A-pillar obstructions impair the driver’s line of sight. This study examines the relationship between intersection geometric configurations and driver eye positions and their effect on pedestrian visibility losses caused by A-pillar occlusion during left turns. A microscopic simulation framework was developed using 3D point clouds from 198 left-turn movements in Edmonton, Alberta, integrating 25 driver eye positions per movement to capture realistic seating variability. Ray-tracing methods were applied to quantify A-pillar occlusion and regions outside the driver’s field of view. Occlusion metrics were analyzed in relation to the geometric features, including the lateral distance to the left-turning vehicle, crossing width, and pedestrian crossing length. Results revealed that larger adjacent widths reduced maximum A-pillar blind zones but increased average occlusion, while longer crosswalks decreased average A-pillar occlusions but expanded the area outside the driver’s field of view. Driver eye position significantly influenced occlusion, with positions farther back reducing A-pillar obstruction and positions forward and upward increasing it, resulting in approximately 11% change in average occlusion and 21% in maximum occlusion. These findings underscore the influence of intersection geometry and driver seating position on pedestrian visibility and offer a data-driven foundation for proactive intersection design, especially where volume-based criteria may overlook safety risks.