Resonant Cycles and Traffic Signal Performance

Abstract

In recent years, a new principle in signal coordination called resonant cycles emerged. Resonant cycles are single cycle lengths for two-way arterials that are robust and provide consistent performance over a range of traffic volumes. Resonant cycles had only been evaluated on a hypothetical network. This study provides a comprehensive analysis of resonant cycles and signal performance using data gathered from two actual corridors, State Route 77 and 22nd Street in Tucson, AZ., it also provides an application guide that can be found in Figures 11 to 18. Resonant cycles were observed on both corridors for low volume and moderate volume conditions. The benefit of resonant cycles is not having the need of altering the cycle length when traffic volumes change. In this study, resonant cycles resulted in reductions of approximately 9% delay and 20% number of stops. The findings indicated that resonant cycles could be easily found on corridors under low volume scenarios. Also, leading left turn treatments seem to shorten the length of resonant cycles on the study segment of 22nd Street. This research utilized simulation results to conduct a full statistical analysis of the variables affecting signal performance. Prior to this study, research included before and after studies to evaluate signal performance. Statistically significant variables include type of timing, left-turn treatment and type of phasing. Actuated operations, lagging left turn treatments and 8-phase signals are more likely to improve the corridor performance index by 5.5%, 4.0%, and 2.0%, respectively.