Teaching Autonomous Vehicles to Express Interaction Intent during Unprotected Left Turns: A Human-Driving-Prior-Based Trajectory Planning Approach

With the integration of Autonomous Vehicles (AVs) into our transportation systems, their harmonious coexistence with Human-driven Vehicles (HVs) in mixed traffic settings becomes a crucial focus of research. A vital component of this coexistence is the capability of AVs to mimic human-like interaction intentions within the traffic environment. To address this, we propose a novel framework for Unprotected left-turn trajectory planning for AVs, aiming to replicate human driving patterns and facilitate effective communication of social intent. Our framework comprises three stages: trajectory generation, evaluation, and selection. In the generation stage, we use real human-driving trajectory data to define constraints for an anticipated trajectory space, generating candidate motion trajectories that embody intent expression. The evaluation stage employs maximum entropy inverse reinforcement learning (ME-IRL) to assess human trajectory preferences, considering factors such as traffic efficiency, driving comfort, and interactive safety. In the selection stage, we apply a Boltzmann distribution-based method to assign rewards and probabilities to candidate trajectories, thereby facilitating human-like decision-making. We conduct validation of our proposed framework using a real trajectory dataset and perform a comparative analysis against several baseline methods. The results demonstrate the superior performance of our framework in terms of human-likeness, intent expression capability, and computational efficiency. Limited by the length of the text, more details of this research can be found at https://shorturl.at/jqu35