Traffic Microsimulation Modeling to Study a Traffic Signal Incident Reduction Function

Abstract

This paper demonstrates the use of a discrete event traffic micro-simulation model to study the safety impacts of the introduction of an incident reduction (IR) function into a vehicle-actuated traffic signal controller. The IR function is based on that used in signal controllers in Sweden. The IR function is designed to reduce the number of stop-or-go decisions by drivers when caught in the dilemma zone at the onset of the amber signal. A correctly adapted IR function was found to greatly enhance the safety performance of signalized intersections. The simulation experiment described in the paper is based on empirical data from a suburban vehicle-actuated signalized intersection. It was conducted specifically to investigate the effects of the standard IR function on three proximal safety indicators: time to collision, red light violations, and required braking rates. The simulation results demonstrate a significant improvement in the time to collision (22%), red light violations (6%), and required braking rate when the IR function was in operation and a small positive influence on traffic movement through the intersection. Importantly, this study has illustrated the potential for using traffic microsimulation modeling for traffic safety evaluation.