Using Dynamic Maximum Greens to Reduce Traffic Signal Timing Maintenance Needs

The dynamic maximum green feature (dynamic max) allows a local traffic signal controller to determine if a phase failed to serve all waiting vehicles and to adjust its length accordingly in subsequent cycles. This study seeks to determine if use of a generic set of dynamic max parameters can reduce the need for traffic signal timing updates. The study uses software-in-the-loop simulation to investigate if the dynamic max can provide similar throughput, similar delays and reasonable cycle and split performance compared with a well optimized signal. Two sites that operate as isolated uncoordinated intersections in the field, one with high volume and one with low volume, were studied. The results indicate that dynamic max was able to serve equivalent traffic volumes as optimized signals and provided similar average intersection delays. Dynamic max can provide a more equitable distribution of delay and provide reasonable traffic signal operations. The recommended set of parameters based on this limited case study is: maximum green, 20 seconds; dynamic maximum green, 60-120 seconds; and dynamic step, 10 seconds.