A link partitioning approach for real-time control of queue spillbacks on congested arterials

In oversaturated urban traffic conditions when traffic demand exceeds capacity at signalised intersections, queues fail to clear during the allocated green times. Once a queue reaches the upstream intersection in an arterial, a queue spillback occurs that reduces the upstream link capacity. To mitigate the negative impacts of spillbacks, this article introduces a real-time adaptive traffic signal control method for global management of spillbacks along signalised arterials. The key idea of the proposed method is to implement a real-time partitioning of the arterial to detect critical cluster(s) of consecutive links with oversaturated traffic conditions. The partitioning approach enables to develop locally smaller-sized decentralised signal control strategies operating on the most upstream and downstream intersections of each cluster. Micro-simulation investigations on a real-world arterial site demonstrate the benefits of the proposed approach compared to an existing pre-timed signal control strategy and a classical decentralised green extension strategy. Utilising an advanced queue length detection method and specific focus on queue spillbacks prevention, the control strategy leads to significant reduction of congestion, and arterial total delay.