Rear-End Conflict Variation at Signalized Intersections Under Non-lane-Based Traffic Condition

Traffic conflict techniques (TCTs) are one of the most frequently used proactive surrogate safety measures which can be used to estimate traffic safety even before the occurrence of a crash. This study explores the variation in rear-end conflict with respect to signal timing and distance from stop lines at signalized intersections with non-lane-based behavior under mixed traffic conditions. More than 4500 vehicle trajectories were extracted for every 0.2-s interval using a semi-automatic tool from field-recorded video footage from two signalized intersections in India. Two popular surrogate safety measures, time to collision (TTC) and deceleration rate to avoid crash (DRAC), were used to identify critical interaction between different vehicle types at varying threshold values. The temporal variation of traffic conflict showed that the majority of conflicts are happening in the first half of red and green time, whereas more severe conflicts occurred at the beginning of red time. Two-wheelers and three-wheelers showed the highest lateral movement and aggressiveness, resulting in critical vehicle interactions closer to the stop line. Variation in conflict proportion based on lane type showed that smaller vehicles prefer curb-side lanes over median-side lanes. Temporal and spatial distribution of conflict based on vehicle type and conflict severity distribution gives a better understanding of how the signal timing influences traffic safety in non-lane-based mixed traffic conditions. These results can be used most beneficially for enhancing the safety and performance of signalized intersections in developing countries.