This paper presents a set of analytical models for estimating progression adjustment factors (PAFs) to delays at signalised, co-ordinated intersection approaches. The derived models are sensitive to the size and flow rate of platoons, which in turn are affected by the travel time between intersections. The procedure requires data that are readily available from time-space diagrams and flow counts. A comparison of the factors estimated in this study and their Highway Capacity Manual (HCM) counterparts reveals the limitations of the HCM method in predicting levels of service for co-ordinated approaches, especially under excellent or very poor progression scenarios. Finally, an interactive, computerised procedure is presented that carries out the necessary PAF calculations with minimal input requirements.
Samenvatting