Safety assessment of coordinated signalized intersections in a connected vehicle environment: a microsimulation approach

In this study, the safety impact of the coupled implementation of signal coordination and connected vehicles (CVs) is examined in a microsimulation environment created in VISSIM. The Surrogate Safety Assessment Model (SSAM) was implemented to generate results of surrogate safety measures. The findings provided evidence that CVs can improve the safety performance at all market penetration rates (MPRs) of CVs in terms of all performance metrics. In addition, further safety improvements were achieved at higher CV MPRs. It was observed that coordinated signals had lower likelihoods of experiencing collisions compared to uncoordinated signals. Specifically, coordinated signals showed significantly higher time-to-collision (TTC) and post-encroachment time (PET) values when compared to uncoordinated signals at the 100% CV MPR only. Moreover, the impact of CV technologies on reducing the total number of conflicts (TNC) would be stronger than that of traffic signal coordination alone while both would lead to reductions in the TNC.