The incidence of wildfires caused by tree contact with high-voltage power lines has become an increasingly pressing issue in the United States. To prevent such incidents, local safety councils have established minimum clearance regulations between trees and power lines. While most studies have focused on the tree encroachment around power lines during normal weather conditions, recent catastrophic fires have been caused by strong winds. To address this gap in knowledge, we investigated the critical wind speed that heightens the risk of wildfires by calculating the distance between trees and wires. To conduct this study, we used airborne LiDAR data collected from Sonoma County in northern California and analyzed the behavior of a sample tree having a height of 19.2 m under wind loads. Our analysis showed that the main factor determining tree deflection is the ratio of the tree height to the trunk diameter. We also found that, although the probability of fire ignition is typically low under normal conditions, it is likely to increase at a wind speed of approximately 40.3 m/s. In conclusion, this research demonstrates the utility of point cloud data in identifying potentially dangerous trees and reducing the risk of fires.
1 May 2024 in Journal of Management in Engineering
The integration of robotic agents into complex indoor construction environments is increasing, particularly through human–robot collaboration (HRC) and multi-robot collaboration (MRC). These collaborative frameworks hold great potential to enhance productivity and safety. However, indoor construction environments present unique challenges, such as dynamic layouts, constrained spaces, and variable lighting conditions, which complicate the safe and effective deployment of collaborative robot teams. Existing studies have primarily addressed various HRC and MRC challenges in manufacturing, logistics, and outdoor construction, with limited attention given to indoor construction settings. To this end, this review presents a comprehensive analysis of human–robot and multi-robot collaboration methods within various indoor domains and critically evaluates the potential of adopting these methods for indoor construction. This review presents three key contributions: (1) it provides a structured evaluation of current human–robot interaction techniques and safety-enhancing methods; (2) it presents a summary of state-of-the-art multi-robot collaboration frameworks, including task allocation, mapping, and coordination; and (3) it identifies major limitations in current systems and provides research directions for enabling scalable, robust, and context-aware collaboration in indoor construction. By bridging the gap between current robotic collaboration methods and the needs of indoor construction, this review lays the foundation for the development of adaptive and optimized collaborative robot deployment frameworks for indoor built environments.
Pedestrian safety near construction sites is increasingly threatened by sidewalk obstructions such as materials and equipment. Despite growing attention to pedestrian-friendly environments, few studies have quantified how such visual encroachments affect the perceived risk. This study introduces a novel image-based framework that integrates the Segment Anything Model (SAM) for the object-level segmentation of sidewalks, obstructions, and barriers in 61 real-world street images. The results revealed significant differences in the perceived risk across four sidewalk environment types, defined by the presence or absence of obstructions and barriers. In addition, the proportion of sidewalk occupied by obstructions was strongly correlated with the perceived risk, whereas the relative size of barriers had no significant effect. This study provides a practical understanding of how temporary obstructions and barriers affect pedestrians’ perceived risk, supporting more effective safety management in urban construction environments. It also contributes to advances in research by providing an objective method for assessing visible hazards using advanced image segmentation techniques.
1 September 2025 in Journal of Construction Engineering and Management