Resonant Cycles in Traffic Signal Control

Abstract

The potential benefits of using resonant cycle times in traffic signal control on an arterial are investigated. Resonant cycles are cycle lengths that result in good arterial progression over a range of traffic flows. The notion of resonant cycle times contrasts with the prevalent adaptive control practice of setting the arterial cycle length in proportion to flow levels at the most congested intersection on the arterial. This research was motivated by the development of appropriate adaptive algorithms for closed-loop system control in the FHWA ACS-Lite project. Simulation experiments with TRANSYT-7F for a four-intersection arterial and additional time–space diagrams demonstrate the characteristics of resonant cycle times and the substantial performance benefits that they may offer. In addition, a systematic method was developed to identify appropriate resonant cycle times and fine-tune a schedule for a time-of-day signal timing strategy.