Estimation of Green Times and Cycle Time for Vehicle-Actuated Signals

An analytical method for estimating average green times and cycle time of vehicle-actuated signals is presented. The examination is limited to the operation of a basic actuated controller that uses passage detectors and a fixed gap time setting. Both fully actuated and semi-actuated control cases are discussed. The practical cycle and green time method for computing fixed-time signal settings is also outlined. A discussion of the arrival headway distributions is presented since the estimation of arrival headways is fundamental to the modelling of actuated signal timings. The method given provides essential information for predicting the performance characteristics (capacity, degree of saturation, delay, queue length, and stop rate) of intersections controlled by actuated signals and for investigating the optimization of actuated controller settings. Further work is needed to validate and calibrate the formulas given using real-life and simulation data.