In this paper, the EVIPAS simulation and optimisation model was used to analyse vehicle-actuated traffic signals. The variables studied were detector type and placement and the settings were for minimum green and vehicle extension. The evaluation criterion was minimum average vehicle delay. The study shows that the optimum design of a vehicle-actuated signal is specific for some variables but is relatively unaffected by others. The design is critical only for high traffic volumes. At low volumes, vehicle delay is relatively unaffected by the design parameters studied in this paper. The most critical variable is vehicle extension, particularly for passage detectors, where it should be at least 4.0 Seconds regardless of detector placement and approach speed. For a presence detector, a short vehicle extension is recommended provided the detector is at least 60 ft in length. A length of 80 ft is preferred. For minimum green, the conventional design practice gives the best delay outputs.
Abstract