Local feedback-based mainstream traffic flow control on freeways using variable speed limits

Recent research has proposed Mainstream Traffic Flow Control (MTFC), enabled via variable speed limits (VSL), as a novel freeway traffic management tool and has demonstrated its efficiency based on sophisticated optimal control methods that may face difficulties in practical field implementations. A simple local MTFC feedback controller is designed in this paper, taking into account a number of practical requirements and restrictions. The MTFC controller relies only on readily available real-time measurements and is robust and suitable for field implementations. The controller is evaluated in simulation and compared to the optimal control results. The controller´s performance is shown to approach the optimal control results, whilst considering several practical and safety restrictions, for a number of investigated scenarios.