Core Insights - The article discusses the evolution and importance of planning modules in autonomous driving, emphasizing the need for engineers to understand both traditional and machine learning-based approaches to effectively address challenges in the field [5][8][10]. Group 1: Importance of Planning - Understanding planning is crucial for engineers, especially in the context of autonomous driving, as it allows for better service to downstream customers and enhances problem-solving capabilities [8][10]. - The transition from rule-based systems to machine learning systems in planning will likely see a coexistence of both methods for an extended period, with a gradual shift in their usage ratio from 8:2 to 2:8 [8][10]. Group 2: Planning System Overview - The planning system in autonomous vehicles is essential for generating safe, comfortable, and efficient driving trajectories, relying on inputs from perception outputs [11][12]. - Traditional planning modules consist of global path planning, behavior planning, and trajectory planning, with behavior and trajectory planning often working in tandem [12]. Group 3: Challenges in Planning - A significant challenge in the planning technology stack is the lack of standardized terminology, leading to confusion in both academic and industrial contexts [15]. - The article highlights the need for a unified approach to behavior planning, as the current lack of consensus on semantic actions limits the effectiveness of planning systems [18]. Group 4: Planning Techniques - The article outlines three primary tools used in planning: search, sampling, and optimization, each with its own methodologies and applications in autonomous driving [24][41]. - Search methods, such as Dijkstra and A* algorithms, are popular for path planning, while sampling methods like Monte Carlo are used for evaluating numerous options quickly [25][32]. Group 5: Industrial Practices - The article discusses the distinction between decoupled and joint spatiotemporal planning methods, with decoupled solutions being easier to implement but potentially less optimal in complex scenarios [52][54]. - The Apollo EM planner is presented as an example of a decoupled planning approach, which simplifies the problem by breaking it into two-dimensional issues [56][58]. Group 6: Decision-Making in Autonomous Driving - Decision-making in autonomous driving focuses on interactions with other road users, addressing uncertainties and dynamic behaviors that complicate planning [68][69]. - The use of Markov Decision Processes (MDP) and Partially Observable Markov Decision Processes (POMDP) frameworks is essential for handling the probabilistic nature of interactions in driving scenarios [70][74].