Spatial scale effects of transportation, social and natural attributes of street environments on perceived activity opportunities for older adults

The street environment correlates with perceived activity opportunities for older adults. While numerous studies have examined the transportation and social attributes of street environments, the natural attributes have been less explored. Furthermore, the nonlinear relationship between the street environment and perceived activity opportunities across different spatial scales remains under-researched. We hypothesize that transportation, social, and natural attributes influence perceived activity opportunities, and their nonlinear effects vary across spatial scales. Therefore, we used activity survey data and multi-source big data from Dalian, China. Employing gradient boosted decision tree (GBDT) methods, we evaluated the nonlinear correlation between the street environment and perceived activity opportunities. Our study considered three community life circle scales: 5-min, 10-min, and 15-min. The results indicated that street features varied significantly at different spatial scales. Specifically, factors such as density of street network, diversity of street interface, distance to the nearest public transport station, accessibility of green space, diversion ratio, and distance to the nearest blue space notably influence perceived activity opportunities across these scales. The study also found that the nonlinear correlations between street environments and perceived activity opportunities were prevalent and varied across spatial scales. These results suggest that priorities for street environment improvements should account for these spatial scale variations. Our research provides multi-scale recommendations for the development of sustainable transportation, age-friendly communities, and the promotion of aging in place.