Coordinated trajectory planning for lane-changing in the weaving areas of dedicated lanes for connected and automated vehicles

Connected and automated vehicle (CAV) technology is widely recognized as a promising way to improve traffic safety, fuel efficiency and network throughput. However, at the early stage of CAV adoption, there will inevitably be a long period when both CAVs and regular vehicles coexist in the traffic system. To facilitate CAV functionalities in mixed traffic, providing dedicated rights of way for CAVs is necessary. In such scenarios, traffic control requires careful design in the weaving areas that allow CAVs to transfer between dedicated roads and ordinary roads for both safety and efficiency considerations. This paper proposes a dynamic programming approach for the coordinated trajectory planning of CAVs in mandatory lane-changing scenarios, in which CAVs have to switch from a dedicated CAV lane into parallel ordinary lanes with mixed traffic. For a group of CAVs that are poised to enter the ordinary road, the proposed method aims to provide each CAV with a suggested lane-changing gap and a reference trajectory in a coordinated manner. To solve the problem, we establish a dynamic programming formulation to determine the suggested gaps for all CAVs. We formulate a nonconvex quadratic-constrained quadratic programming (QCQP) problem to characterize the trajectory determination problem, and a relaxation-based approximate algorithm is developed to solve the QCQP. Simulation results show that, compared to the benchmark methods, the proposed method offers substantial benefits both in terms of traffic efficiency and in-vehicle passengers experiences.