Urban Planning in the 15-Minute City: Revisited under Sustainable and Smart City Developments until 2030

The 15-minute-city concept represents an increasingly popular urban policymaking and planning paradigm that seeks to shift attention to the neighborhood as a “place” rather merely a spatial and functional planning unit. The core premise of the concept is that critical urban services and amenities should be reachable within 15 min of walking or cycling from a residence. The urban-planning principles that enable the realization of the 15-minute city variably embody planning in mixed-use neighborhood units, proximity-based planning, planning for active transport, citizen participation in planning, and innovation and intelligence-driven planning. We revisit these urban-planning premises in the light of emerging social, physical, and structural developments through 2030, with a focus on European cases. The findings provide important additions and recommendations to the urban-planning principles of 15-minute cities along the themes of proximity-based planning, the use of land and urban form, urban governance and citizen participation, and inclusive digitalization. The paper moves the discussion on the 15-minute city forward and will be helpful for urban planners, policymakers, and scholars seeking to envision and create a more sustainable, inclusive, and vibrant future in cities.