Real- time prediction of adaptive traffic signal timings and queue lengths.

The calculation of dynamic advisory speeds, to assist drivers in finding a path through successive green signals, requires advance knowledge of signal timings, vehicle to signal distances and queue lengths.Under a traffic adaptive signal system (e.g. the Sydney Co- ordinated Adaptive Traffic System, SCATS) the prediction of signal timings and queue lengths is complicated by the variability of cycle, phase split and offset times as well as by the different phasing arrangements provided for each intersection. A general method of signal timing prediction is described, based on exponential smoothing of recent historical data from SCATS, and software for application each second to 11 intersection approaches in Melbourne is outlined.