Simple abstract models to study stability of urban networks with decentralized signal control

Traffic Signal Controllers (TSCs) used to manage intersections can influence the residual queues at intersections. These residual queues can lead to an irreversible state of network gridlock. This paper discovers the advantages of locally adaptive TSCs utilizing traffic information on both upstream and downstream approaches of an intersection (e.g., back-pressure or BP control) over employing only upstream approaches information (e.g., proportional control) in avoiding gridlock. Although BP algorithms are mathematically proven to be throughput optimal as they bound network queues for all feasible demands, the proofs exist only for networks with infinite link capacities, fixed-route choices, or for TSCs with no minimum green-time requirement.