Explaining distance deterrence variation in urban mobility with spatiotemporal features

Distance deterrence, often quantified through the gravity model, has been used to characterize urban mobility, yet which urban and contextual features are linked with its within-city variation remains unclear. Using large-scale origin–destination mobility data comprising about 4.8 billion trips across the Seoul Metropolitan Area, we show that distance deterrence follows a core–periphery pattern and varies with transit accessibility, day-off conditions, and age-specific temporal patterns. To do so, we estimate town-level distance exponents with a gravity model and examine their spatial and temporal variation using XGBoost interpreted with SHapley Additive exPlanations (SHAP). We find that distance deterrence generally strengthens from core toward the periphery, but localized areas of weak deterrence appear near major metro stations. This spatial pattern is also accompanied by temporal variation. Distance deterrence generally increases from morning to afternoon and decreases during day-off periods, but the day-off pattern reverses among working-age groups in transit-rich urban cores. Together, transit accessibility emerges as a key factor associated with lower distance deterrence overall, with associations that vary across time and population groups. These findings suggest that distance deterrence reflects nonlinear and complex relationships with urban structure, transit accessibility, and sociotemporal factors, making it a spatiotemporally sensitive indicator of accessibility disparities across urban space.