Proximity, observed human presence, and urban vitality: an empirical assessment of the 15-minute city

The 15-minute city (15MC) framework advances the principle that organizing daily services within walking distance supports local activity and reduces dependence on motorized travel. Despite widespread adoption, systematic empirical evidence linking 15MC accessibility to observed human presence across temporal scales remains limited. This study evaluates the relationship between 15MC accessibility, observed human presence, and urban vitality indicators (UVIs) in Tallinn, Estonia. The study integrates 15MC service catchment measures, mobile network digital footprint data across six observation periods, and UVIs representing structural and social characteristics of the built environment, analyzed using Spearman’s rank correlation and spatial lag regression across a 250 m grid. Results indicate that higher accessibility is associated with greater observed human presence, stable across all observed months, and positively associated with land-use diversity, intersection density, socio-economic diversity, and population density. A strong spatial autoregressive effect indicates that observed presence patterns are spatially interdependent beyond local accessibility, highlighting the limitations of proximity as a standalone planning criterion. These findings suggest that proximity alone does not fully explain observed urban activity patterns. Urban stakeholders should complement static accessibility thresholds with temporally observed human presence data and integrate UVIs into 15MC evaluation frameworks for an empirically grounded basis for proximity-based planning.