Autonomous vehicles (AVs) may use external interfaces, such as LED light bands, to communicate with pedestrians safely and intuitively. While previous research has demonstrated the effectiveness of these interfaces in simple traffic scenarios involving one pedestrian and one vehicle, their performance in more complex scenarios with multiple road users remains unclear. The scalability of AV external communication has therefore attracted increasing attention, prompting the need for further investigation. This scoping review synthesises information from 54 papers to identify seven key scalability issues in multi-vehicle and multi-pedestrian environments, with Clarity of Recipients, Information Overload, and Multi-Lane Safety emerging as the most pressing concerns. To guide future research in scalable AV-pedestrian interactions, we propose high-level design directions focused on three communication loci: vehicle, infrastructure, and pedestrian. Our work contributes the groundwork and a roadmap for designing simplified, coordinated, and targeted external AV communication, ultimately improving safety and efficiency in complex traffic scenarios.

翻译：自动驾驶车辆（AVs）可使用外部接口（如LED灯带）与行人进行安全、直观的通信。先前研究已证明这些接口在涉及单一车辆和单一行人的简单交通场景中的有效性，但其在包含多个道路使用者的复杂场景中的表现尚不明晰。AV外部通信的可扩展性因此受到日益关注，亟需进一步探究。本范围综述整合54篇论文的信息，归纳出多车辆-多行人环境中的七大关键可扩展性问题，其中接收者明确性、信息过载及多车道安全性成为最紧迫的挑战。为引导未来可扩展性AV-行人交互研究，我们提出聚焦于车辆、基础设施和行人三类通信节点的高阶设计方向。本工作为设计简化、协调且有针对性的AV外部通信奠定基础并提供路线图，最终提升复杂交通场景中的安全性与效率。