Group-based optimisation of signal timings using parallel computing

Abstract

This paper presents the use of parallel computing in the group-based optimisation of signal timings for area traffic control. The scope of parallel computing to speed up the optimisation heuristics, consisting of a mixture of network-wide steps, in which control variables for signal settings at all junctions are changed simultaneously, and junction-based steps, in which the variables at each junction are changed in turn, is examined. Parallel algorithms and a dynamic load balancing scheme are developed for these optimisation heuristics. A trial network from Leicestershire, England is used to demonstrate the performance of parallel computing. A useful saving in computing time is obtained for the example of the standard optimisation procedure, and for the examples of random offsets calculation and sequencing analysis substantial reductions of computing times are achieved. In general, the performance of parallel computing in group-based optimisation of signal timings improves as the number of independent paths in the task schedule increases. © 1997 Elsevier Science Ltd.