Safety evaluation of unsignalized intersection with heterogeneous traffic using Post Encroachment Time and conflicting vehicle speed

Abstract

Road safety assessment is more challenging in developing countries because crash data are not generally available. However, use of surrogate safety measures can act as a substitute for actual crash data. Historically, the unsignalized intersection poses more danger for road users and the Post Encroachment Time (PET) is more suitable for traverse collision. A threshold value for identifying the critical conflict is inappropriate for heterogeneous traffic conditions. Further, spotting the critical conflicts only by using the speed of the following vehicle is also not ideal. This study includes the speed of the leading vehicle for finding the critical conflicts as the collision probability also depends on the speed of the leading vehicle. Initially, the unsignalized intersections considered looked unsafe while observing the average PET value. However, considering the results of the critical conflicts both interections were found to be safe. It is also observed that the fast-moving vehicles were more responsible for critical conflicts.