Evaluation of traffic safety at un-signalized intersections using microsimulation: a utilization of proximal safety indicators

In many cases crashes at intersections account for over 50% of all urban road crashes. The need to reduce these crashes has fostered considerable research on the development and evaluation of traffic safety at intersections. This paper introduces a micro-level behavioral approach for estimating the crash potential at unsignalized intersections for different traffic conditions. To this end, proximal safety indicators which represent the temporal and spatial proximity characteristics of unsafe interactions and near-accidents are explored and a practical implementation of post-encroachment time (PET) is carried out in the safety evaluation process. Simulation results demonstrate the sensitivity of PET to changes in the speed limit on roads and show that it can be used to carry out safety evaluations of uncontrolled intersections. More generally, the ability of microsimulation to evaluate safety effects of policy measures like speed limit is demonstrated.