This project began with the question of whether a road agency should use more detectors upstream of the stopline of a road link. The review in this report came to the conclusion that an extra set of upstream detectors on an arterial road link could possibly provide useful data for the measurement of network performance and adaptive traffic control. However, detectors and communication equipment are expensive to install and maintain. New software for queue formation and dissipation needs to be developed in SCATS and STREAMS to fruitfully utilise the upstream demand-side information from upstream detectors and the downstream supply-side information from stopline detectors. It is therefore recommended that road agencies begin with better utilising of the existing detector data — not just from a specific intersection, but also from one or more intersections upstream and downstream. This study successfully employed the AIMSUN microsimulation package to identify some principles underlying the implementation of pre-emption and gating schemes in an ATC system. The pre-emption results confirm the benefit of pre-emption, the use of stopline detectors and the use of pre-emption before queue spillback occurs. The gating results suggest that the primary goal of gating is not travel time or delay reduction on a route, but the effective utilisation of green times in a cycle when the through movement was blocked. Gating at an intersection can increase overall network throughput and reduce overall network delay when the side-street traffic volume is significant and congested, provided there is storage room for turning movements to queue on the main road. (Author/publisher)
Abstract