Optimisation Through Control in Dynamic Traffic Networks
R. Mounce (School of Management, Queen’s University, Belfast, UK)
There is clearly a need for optimising traffic systems in order to reduce congestion and improve network reliability. The system optimal assignment is the traffic flow pattern that minimises total network costs. However, travellers are not under any centralised control; but instead reroute in order to minimise their own travel costs. Therefore any strategy to control a network must take account of travellers’ rerouting. Traffic signals are an integral part of traffic systems that provide a ready-made way of controlling it. Responsive signal policies modify green times in response to variations in traffic flow. Stability of a traffic system is important for many reasons such as network reliability and planning. In order for a responsive traffic control system to be stable, it must be stable with respect to its own rules and with respect to travellers’ rerouting.