SPERT: A speed limit strategy for recurrent traffic jams

This paper proposes and simulates a speed limit controller for recurrent traffic jams (SPERT). SPERT is a simple yet efficient variable speed limit (VSL) control strategy based on the behavior of the optimal controller without any need for online optimization. The online implementation of SPERT is a simple rule-based controller that activates and deactivates the corresponding variable speed limit when the densities of the dominant bottlenecks (which are found offline) reach predefined thresholds. These thresholds are defined in order to activate and deactivate the speed limits at the same bottleneck density at which they would be activated or deactivated in the nominal case. The simulation results show that SPERT is able to approach the optimal behavior while eliminating online computational cost, increasing robustness, and outperforming previously proposed easy-to-implement VSL control algorithms.