Cooperative Lane Changing Strategies for Connected and Automated Vehicles in Weaving Areas

Weaving area is one of the typical traffic bottlenecks of urban expressway and its traffic dynamics are very complex. With the development of vehicle intelligence and network technology, automatic vehicle driving and real-time dynamic communication become possible, which provides technical support for the control of vehicle group behavior in weaving areas. In this paper, the cooperative lane changing among on-ramp vehicles, off-ramp vehicles and straight driving vehicles in weaving areas of the urban expressway is studied. Based on the analysis of traffic characteristics in weaving areas under the environment of connected and automated vehicles (CAVs), four cooperative strategies for vehicle groups in the weaving area based on different road spatial flow-balance are proposed. The simulation model of the weaving area is built with VISSIM simulation software, and the proposed optimization schemes are simulated and compared. The results show that the four strategies have similar effects when the traffic volume on the mainline and on-ramp are both low. In other states, the strategy of off-ramp vehicles preferentially distributed in the outer lane is superior to the strategy of off-ramp vehicles with different distribution ratios in each lane of the mainline, that is, the strategy of inducing or controlling all off-ramp vehicles to the outermost lane in advance before entering the deceleration lane (for example, the ratio of off-ramp vehicles in three lanes is 0:0:1). This paper intends to provide theoretical support for reducing vehicle conflicts and improving traffic safety and traffic efficiency in urban expressway weaving areas under the CAV environment.