From Static Proximity to Dynamic Accessibility: Integrating Smart-City Data into the 15-Minute City

Abstract

The 15-minute city has become an influential framework for proximity-based urban planning, but most operational assessments remain comparatively static: they measure whether destinations lie within a specified travel-time threshold under assumed network conditions. Smart-city infrastructures create the possibility of a more temporally responsive model. This article develops the concept of Dynamic 15-Minute Accessibility, in which neighborhood accessibility is evaluated across time using changing transit supply, congestion, operating hours, shared-mobility availability, pedestrian conditions, and other observable urban conditions. Drawing on recent research on human mobility, multimodal accessibility, GIS-based 15-minute-city measurement, smart technologies, and inclusive proximity planning, the article distinguishes potential accessibility from realized and reliable accessibility. It proposes a Dynamic Accessibility Index organized around destination availability, network travel time, service reliability, temporal availability, universal accessibility, and data confidence. Paris is used as the conceptual policy anchor, with implications for cities seeking to combine proximity planning with digital twins and real-time mobility systems. The article argues that smart-city technology is most valuable to the 15-minute-city agenda when it reveals temporal and social accessibility gaps rather than merely adding technological sophistication.