Risk Assessment and Trajectory Planning for Overtaking of Autonomous Vehicles on Two-lane Two-way Roads

Among the applications of intelligent traffic system, two-lane two-way urban roads are very important scenarios for autonomous vehicles. Overtaking across the dividing line is a dangerous maneuver because of the high risk of collision with vehicles in the opposite lane. In this paper, the uncertainties of time-to-collision (TTC) are handled by unscented transformation algorithm, and nonlinear interpolation is also employed. Then we develop the overtaking risk indicator (ORI) by calculating the TTC of the ego vehicle and obstacles in all the two lanes to evaluate the risk of overtaking. Finally, a trajectory planning scheme integrated with the risk indicator and model predictive control (MPC) algorithm is designed to improve the safety and efficiency of overtaking. Simulation results verify the reliable performance of the proposed method.