Has the Development of the 15-min Community Life Circle Improved Residents’ Access to Public Service Facilities? Evidence from Nanjing, China, 2018–2024

The 15-min community life circle (15-min CLC) aims to improve access to daily services and promote social equity. However, few studies have examined changes in accessibility and accessibility inequality across age groups over time. This study investigates these changes in Nanjing’s main urban area from 2018 to 2024. Facility weights were incorporated into the Gaussian two-step floating catchment area (G2SFCA) method to assess accessibility to public service facilities. The Dagum Gini coefficient was used to measure accessibility inequality, and XGBoost-SHAP was employed to assess the relative importance of influencing factors and explore their nonlinear relationships with accessibility. Overall, accessibility increased and inequality decreased, but these changes varied across areas and age groups. Accessibility remained higher in the inner city and inner suburb, where service provision continued to improve. Other areas experienced mainly localized facility additions, and core–periphery disparities persisted. Residents aged 15–59 years experienced greater gains in accessibility, while older adults showed limited improvements and continued to face greater accessibility inequality. Community location, built environment, and housing attributes showed nonlinear relationships with accessibility and threshold effects. These findings suggest that increased facility provision does not necessarily improve accessibility or reduce accessibility inequality. Urban policymakers and planners must continue to advance 15-min CLC planning in the future, but facility provision should be tailored more carefully to different needs of residents.