Beyond the calendar: Exploring the relationship between destination built environment and active travel under the 15-minute city concept

The 15-minute city concept has been widely adopted as a spatial blueprint for sustainable urban futures. However, existing research has largely neglected the temporal dimension of the 15-minute city, particularly the interaction between daily and weekly human activity patterns and the built environment, which may affect the effective implementation of 15-minute city policies. In this study, we pioneer a spatiotemporally bounded analysis within 15-minute active travel ranges (walking/cycling ≤ 15 min), utilizing high-resolution mobility data from China’s Unicom Smart Footprint Platform to analyze the impacts of destination built environment on active travel volume, distance, and duration across different calendar events (weekdays and weekends). Our analysis revealed two distinct patterns shaping active travel: calendar-invariant and calendar-sensitive factors. The density of amenities (DA) emerged as a strong, calendar-independent predictor, positively correlated with all active travel indicators (travel volume, distance, and duration). The functional mix index (MIX) was positively associated with active travel volume and distance on weekdays and weekends. Conversely, multiple built environment factors demonstrated significant temporal variation. Accessibility to public service facilities (A_PSF) inhibited active travel volume and distance on weekdays, while the density of sports and leisure facilities (D_SLF) influenced these travel metrics on weekends. These findings provide urban planners with a differentiated governance framework, emphasizing the development of stable core infrastructure (e.g., amenity clusters) and dynamically optimizing sensitive facilities (e.g., leisure hubs) to accommodate weekday–weekend demand. This spatiotemporal strategy enables better implementation of the 15-minute city, facilitating low-carbon transport transitions while enhancing urban resilience.