Title

BENEFIT SENSITIVITIES OF ADAPTIVE TRAFFIC CONTROL STRATEGIES AT ISOLATED TRAFFIC SIGNALS

Document Type

Journal Article

Publication Date

1999

Subject Area

operations - traffic, infrastructure - traffic signals, ridership - demand, economics - benefits

Keywords

Travel models (Travel demand), Travel demand, Traffic delay, Time of day, Signalized intersections, Signalised intersections, Pretimed traffic signal controllers, Pretimed control, Periods of the day, Isolated intersections, Fixed time traffic signals, Fixed time controllers, Estimates, Benefits, Adaptive systems, Adaptive control, Actuated traffic signal controllers

Abstract

A study of the possible benefits of using traffic adaptive and actuated signal control strategies at traffic signals is described here. The study indicated that delay estimates produced by INTEGRATION closely matched the delay estimates of the 1997 revision to the U.S. Highway Capacity Manual. Second, benefits of time-of-day control and adaptive control became more pronounced as the level of demand peaking increased. Third, well-designed time-of-day plans easily outperform fixed-time and adaptive strategies when the prevailing traffic demands match the controller's expectations. Adaptive strategies performed better than simple fixed-time control strategies, which were optimized only for the average demand level. It was also observed that all types of control strategies, especially adaptive control strategies, could be improved by introducing signal actuation. Finally, it was found that actuation improved the performance of the intersection for both uniform and random departure headways. Improvements were greatest when an adaptive control strategy was being implemented and the departure headway was random.