Climate-sensitive street design: Evaluating summer pedestrian activity and behavioral thermal adaptation on the high line, NYC

With climate change, summer heat stress poses a critical challenge to urban residents, impacting public health and outdoor activities. Despite growing attention to outdoor thermal comfort, behavioral thermal adaptation—how individuals adjust behavior to seek thermally comfortable spaces—remains understudied. This study addresses this gap by examining how climate-sensitive street design mediates the relationship between outdoor thermal comfort and pedestrian activity, focusing on The High Line, New York City. Using on-site microclimate measurements and unobtrusive video observations at five sites, panel data analysis evaluates street design’s influence on pedestrian activity and identifies thermal threshold levels. Key findings reveal that The High Line maintained cooler conditions than Mid-Manhattan, primary due to its high vegetation density and proximity to the river. Street geometry—defined by parameters such as Sky View Factor (SVF), Tree Canopy Cover Ratio (TCCR), and Height-to-Width (H/W) ratio—played a significant role in shaping solar exposure and influencing pedestrians’ thermal comfort. Walking Density (WD) was largely driven by air temperature, whereas Stationary Ratio (SR) and Seat Occupancy Ratio (SOR) were more sensitive to solar radiation and shading. Additionally, lower SVFs correlated with higher tolerance for air temperature, emphasizing the critical role of shade in improving thermal comfort. By establishing data-driven thermal thresholds, our findings provide empirical benchmarks for climate-sensitive street design. This study advances urban climate research by linking microclimate data with behavioral responses, offering a novel framework for heat-resilient street design.