What is it about?

Socially compliant automated vehicles (SCAVs) represent a crucial step toward safer, more efficient, and human-centric mixed-traffic environments. Researchers from Delft University of Technology and RWTH Aachen University conducted a comprehensive review and expert survey on SCAVs, identifying key gaps and opportunities for embedding social intelligence into automated driving systems. The resulting conceptual framework integrates sensing, socially aware decision-making, safety constraints, spatial‑temporal memory, and bidirectional behavioral adaptation, enabling AVs to learn from and respond to human drivers. The proposed interdisciplinary pipeline bridges technology and human behavior, paving the way for automated vehicles that not only drive safely but also drive socially.

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Why is it important?

Automated vehicles (AVs) hold promise for revolutionizing transportation by improving road safety, traffic efficiency, and overall mobility. Despite the steady advancement in high-level AVs in recent years, the transition to full automation entails a period of mixed traffic, where AVs of varying automation levels coexist with human-driven vehicles (HDVs). Making AVs socially compliant and understood by human drivers is expected to improve the safety and efficiency of mixed traffic. Thus, ensuring AVs’ compatibility with HDVs and social acceptance is crucial for their successful and seamless integration into mixed traffic. Researchers at Delft University of Technology (Netherlands) and RWTH Aachen University (Germany) carried out a study with a comprehensive scoping review to assess the current state of the art in developing socially compliant automated vehicles (SCAVs), identifying key concepts, methodological approaches, and research gaps. They conducted an informal expert interview to discuss the literature review results and identify critical research challenges and expectations towards SCAVs. Based on the scoping review and expert interview input, they designed a conceptual framework for the development of SCAVs and evaluated it using an online survey targeting researchers, technicians, policymakers, and other relevant professionals worldwide. The framework outlines the key capability elements necessary for SCAVs and incorporates crucial considerations across technical, social, and cultural dimensions, effectively bridging theoretical insights with practical applications to achieve socially compliant automation. The conceptual framework provides actionable insights into developing and embedding social compliance in AV systems, enabling scalable and context-sensitive deployment. It can also foster collaboration among academia, industry, and policymakers, ensuring technical innovation aligns with societal needs and regulatory standards, accelerating the path toward SCAV and further towards safe and socially inclusive automated mobility solutions.

Perspectives

Five methodological pillars In reviewing 68 pivotal studies on SCAVs, the team clustered existing approaches into five main categories: • Imitation learning to clone human social driving norms • Reinforcement learning with utility-based models • Model‑based (e.g., game theory, social‑force models, and driving risk field models) generation of human-like behaviors • Socially‑aware trajectory prediction with social factors and machine learning • Optimization of social driving parameters balancing safety, comfort, and courtesy Expert insights reveal critical gaps Through informal interviews with ten AV experts across academia, industry, and government, the authors uncovered key limitations in today’s AVs: • Excessive conservatism, leading to inefficient traffic flow • Poor interpretation of implicit human cues, from hand gestures to assertive lane changes • Inflexibility to diverse driving cultures and styles • Lack of bidirectional adaptation, where AVs and human drivers dynamically adjust to each other A novel conceptual framework To address these gaps, the author team proposes a novel conceptual framework for SCAV comprising: • Sensing & perception module, fusing multi-modal sensor data • Socially‑compliant decision‑making module, embedding social components (including culture, norms, and cues), different driving styles (e.g., aggressive, cautious, pro-social), and bidirectional behavioral adaptation mechanisms • Safety constraints module, a real‑time safeguard layer • Utility trade‑off mechanisms, balancing individual vehicles’ benefits with network‑level traffic performance • Bidirectional behavioral adaptation, enabling AVs to learn from and respond to human drivers’ adaptations (there will be bidirectional iterative adaptations between AVs and human drivers) • Spatial‑temporal memory module, continuously updating AV models with past interaction data to facilitate the long- and short-term updating of knowledge and driving rules and contribute to the implementation of bidirectional behavioral adaptation.

Yongqi Dong
Technische Universiteit Delft

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This page is a summary of: Toward developing socially compliant automated vehicles: Advances, expert insights, and a conceptual framework, Communications in Transportation Research, December 2025, Tsinghua University Press,
DOI: 10.1016/j.commtr.2025.100207.
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