Post encroachment time (pet) to estimate crash risk of right-turn vehicles entering two-way two lane divided highways

Abstract

When a minor road vehicle enters a multi-lane highway with a right turn, higher number of conflict points are created due to the complexity of the vehicle trajectories. Right turn vehicle entering a two-lane two-way divided highway from a minor road, therefore created four conflict points including 3 crossing conflict points and one merging conflict point. This research study focuses on minimizing the imposed Crash Risk due to a right-turn vehicle entering from a minor road to a two-lane two-way divided highway at an unsignalized T-intersection. Crash Risk is defined using Post Encroachment Time (PET). Data obtained from CCTV recordings were extracted using a tracker software to find PET related to each conflict. PET data was represented as percentage cumulative frequency graphs, and thereby estimated the percentile PET values. 15th percentile cumulative frequency of conflicts are at 2.4s, 1.4s, 3.0s and 6.0s of PET values in the 1st, 2nd, 3rd and 4th lanes respectively. Out of 4 lanes based on 15th percentile PET value, 2nd lane seems to be the most critical lane.