One way to improve safety of signalized arterials is to optimize signal timings. Historically, signal retiming tools were used to reduce traffic delay and stops and other measures of traffic efficiency. The concept of optimizing signal timings specifically to improve safety metrics, or their surrogate measures, is not common in current signal timing optimization practice. This study advocates a fresh approach to integrating VISSIM microsimulation software, SSAM, and VISGAOST for optimizing signal timings to reduce surrogate safety measures and thereby reduce risks of potential real-world crashes. In addition, a multiple-objective genetic algorithm is implemented into VISGAOST to identify the optimal compromise between two competing objectives: surrogate safety and traffic efficiency. A 12-intersection corridor on Glades Road in Boca Raton served as a case study. Optimized signal timings delivered a solution that balanced both safety and efficiency. When compared to initial signal timings the estimated number of conflicts was reduced by 7%. In addition, when compared to signal timings optimized for efficiency the estimated number of conflicts was reduced by 9% without a significant loss of efficiency (~1%). The study also approximated a Pareto Front of conflicts and throughput which may be instrumental when trading off (surrogate) safety for efficiency in the development of signal timing plans. Further research is needed to test the approach on a variety of networks and traffic conditions and to find a good composite measure for single-objective optimizations.
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