In Under-saturated conditions, delay minimization and bandwidth maximization are the two main objectives that are used to optimize traffic signals in arterial networks. Targeting one or both of these objectives may not result in effective operations during oversaturated conditions. In order to possibly maintain optimal states of traffic during over-saturated conditions or transitions between unsaturated and over-saturated conditions, control strategies should be developed and formulated based on an integrated criterion that combined throughput maximization, delay minimization and queue management through a multi-objective analysis framework. This paper provides a closed-form formula for the control plan scheduling problem assuming three regimes of operation during an oversaturated control situation: loading, processing, and recovery. The formulation identifies the optimal timing plans for different control objectives in each regime and the optimal point to switch from one plan to the next, which is not typically addressed in traditional signal timing optimization tools. The impacts of switching points on network critical routes travel time were assessed. The simulation results of Post Oak network show significant improvements due to the application of the proposed timing procedure. In particular, the test case also revealed that throughput maximization control during the loading regime provides the network with extra reserve capacities on the critical routes which improves total performance versus other combinations of control objectives.
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