The task of executing left turns at signal-free T-shaped intersections without protective signals poses a critical challenge in the realm of autonomous driving. Conventional rule-based approaches tend to be excessively cautious, rendering them inadequate for effectively managing driving tasks within unpredictable T-shaped intersection environments. In the case of complex traffic scenarios, a single model is less effective in convergence and has a lower pass rate and poorer safety. Thus, this study introduces a multi-layer reinforcement learning model, employing D3QN (Dueling Double DQN) and TD3 (Twin Delayed Deep Deterministic policy gradient algorithm) for advanced behavioral decision-making and vertical acceleration planning, respectively. In our experimental investigation, we designed four simulation scenarios based on the driving behavior of the Carla simulator to replicate real-world driving conditions. Verification and test simulation outcomes substantiate that, in comparison to other single-trained reinforcement learning models, the multi-layer reinforcement learning model proposed in this study attains the highest success rate. Specifically, the pass rate in the verification scenario, consistent with the training conditions, achieves an impressive 99.5%. Furthermore, the pass rate in the comprehensive test scenario reaches 89.6%. These experiments unequivocally demonstrate the considerable enhancement in T-shaped intersections pass rates achieved by the proposed method while ensuring both traffic efficiency and safety.

In complex urban scenarios like intersections without dedicated left-turn signals, the construction of planning systems that maximize efficiency while guarantee safety has been a significant challenge. In this paper, we propose a reinforcement learning approach based on curriculum learning using real world dataset, and we develop a partial end-to-end planning and control model capable of adapting to variable temporal and spatial dimensional state inputs, applying it to autonomous driving task. Our model is compared with mainstream reinforcement learning algorithms to validate that our proposed algorithm can effectively solve complex spatio-temporal planning problems. This significantly enhances the efficiency of passing while maintaining a certain level of safety.

By aiming at addressing the left-turning problem of an autonomous vehicle considering the oncoming vehicles at an urban unsignallized intersection, a hierarchical reinforcement learning is proposed and a two-layer model is established to study behaviors of left-turning driving. Compared with the conventional decision-making models with a fixed path, the proposed multi-paths decision-making algorithm with horizontal and vertical strategies can improve the efficiency of autonomous vehicles crossing intersections while ensuring safety.