A survey on proximity monitoring and warning in construction

Abstract: Various technologies have been applied to monitor the proximity between two construction entities, preventing struck-by accidents and thereby enhancing onsite safety. This study comprehensively reviews related efforts dedicated to proximity monitoring and warning (PMW) based on 97 relevant articles published between 2010 and 2024. The bibliometric analysis reveals the technical roadmap over time, as well as the five most influential leaders and the two largest research networks they have established. The qualitative review is then conducted from four perspectives: influencing factor study, hazard level definition and determination, proximity perception, and alarm issuing and receiving. Finally, the limitations and challenges of current proximity perception are discussed, along with corresponding future research directions, including end-to-end three-dimensional (3D) object detection, real-time 3D reconstruction and updating for dynamic construction scenes, and multimodal fusion. This review presents the current research status, limitations, and future directions of PMW, guiding the future development of PMW systems.