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.