Resonant Cycles under various Intersection Spacing, Speeds, and Traffic Signal Operational Treatments

Abstract

In recent years, resonant cycles have emerged as a new principle in signal coordination. Resonant cycles were originally associated with cycle lengths that resulted in good progression over a range of traffic volumes. Several studies documented the potential benefits of this new principle. In this research, “resonant cycles” are defined as cycle lengths that are robust over a range of traffic volumes on two-way arterials. However, resonant cycles may not always exist on traffic corridors, depending on their operational and geometric factors, and the impact of these factors is not well understood. To examine these conditions more closely, this paper provides a comprehensive analysis of resonant cycles. Geometric and operational traffic data obtained from two corridors were used. Resonant cycles were observed on both corridors; the benefits resulted in reductions of approximately 8% in the total delay and 19% in the number of stops when compared with the critical intersection method. The geometric and operational variables that permitted resonant cycles were identified through a macroscopic model. The results indicated that resonant cycles could easily be found on these two corridors under low-volume scenarios. When moderate-volume conditions occurred, certain combinations of geometric and operational traffic variables supported resonant cycles. In contrast, cross-street volumes that were similar in magnitude to the volumes of the main street tended to remove the cycle resonance for moderate traffic volumes. When a microscopic model was used to estimate optimal cycle lengths, the range of traffic volumes under a resonant cycle was reduced.