Investigation of Traffic Conflicts at Unsignalized Intersection for Reckoning Crash Probability Under Mixed Traffic Conditions

抄録

The present study aims at assessing traffic conflicts at unsignalized T-intersection under mixed traffic conditions using Surrogate Safety Measure (SSM), namely Post Encroachment Time (PET). The traffic movement data were collected during peak and off-peak hours at an un-signalized T-intersection having a central island using videography survey technique. Traffic characteristics (classified traffic volume) and PET data were extracted manually for the recorded video. To assess safety, primarily, the extracted PET values were tested for its distribution and Generalized Extreme Value (GEV) was found to be the best-fitted distribution for explaining the temporal variations observed in PET values. This was subsequentlyalso extended to estimate the crash probability. Results indicate that the smaller vehicles have higher safety implication at un-signalized T-intersection. Probability of crash was found to vary substantially with respect to vehicle type and their combination based on offending and conflicting vehicle types, traffic volume and composition.