Traffic Control Strategies for Virtual Emergency Lanes on Expressways

Abstract

Expressway congestion and traffic accidents often hinder the passage of emergency vehicle, while traditional fixed emergency lanes suffer from issues such as low resource utilization and poor adaptability. To address mixed traffic flows comprising connected and automated vehicle, human-driven vehicle, and truck, this paper proposes a dynamic virtual emergency lane control strategy. This strategy creates continuous passage space for emergency vehicle through segmented dynamic allocation of right-of-way and stepwise lane-changing guidance. Based on cellular automata theory, a simulation model for mixed traffic flows is established by integrating the NS model, the IDM following model, and an improved STCA lane-changing rule.Using a 2,000-meter, four-lane expressway as the simulation scenario, the results indicate that, compared to a fixed emergency lane, this strategy can increase peak traffic volume by 30.2% and reduce the congestion rate by 10%–27% under moderate traffic density. It performs best in scenarios with four lanes and a low to moderate proportion of truck. This strategy effectively improves the efficiency of emergency vehicle and the utilization of road resources, making it suitable for emergency management scenarios on smart expressways.