Research was conducted to apply state-of-the-art computer technology to traffic signal control, with emphasis being placed on applications for the small or medium-size city. The most comprehensive analysis of control logic to date coupled with a synthesis of the hardware required for a real-time closed-loop digital-computer-controlled traffic signal system is presented. Utilizing the city of white plains, n. Y. As a model, a typical computer signal system is specified, equipment is selected, and costs are estimated for its 116 signalised intersections. Based on the analysis presented, it is anticipated that computer control requirements and costs may be estimated for other typical cities in the population class of 50,000 and a trade area serving more than 250,000. Control logic is derived based on the theories of minimum aggregate delay. The equations are presented in a readily usable form for solution by a computer system that is sensing traffic and making control decisions in real time. Needed information pertaining to acceptable criteria for the design and placement of traffic sensing devices is provided. In the control scheme presented, the signal change decisions are based on comparisons of time savings expressed in terms of relative delay and computer-derived predictions of future delays that will be incurred throughout the signalised network.
Abstract