Integrating urban freight into the 15-minute city: Evidence from Poland

The 15mC concept focuses on residents' proximity to basic services but often overlooks the logistical flows needed to sustain them. This paper examines integrating freight distribution into proximity-based urban planning to align with sustainable development goals. While density and mixed land use reduce passenger travel distances, they often paradoxically increase the complexity and frequency of goods movements. This study implements a mixed-method research design: (1) a systematic literature review of international green logistics models, (2) a comparative analysis of European best practices (Paris, Barcelona, Utrecht), and (3) primary empirical research conducted in Poland. The primary research includes semi-structured interviews with municipal planners and a diagnostic survey of last-mile operators and local business owners. The results identify a planning gap in Polish metropolitan areas, where freight is frequently treated as a private commercial issue rather than a public utility. The findings suggest that successful integration requires a tiered infrastructure of decentralized micro-hubs, flexible loading zones, and the promotion of cargo-bike logistics. The paper concludes with a proposed conceptual framework for medium-sized European cities to harmonize freight efficiency with walkable urban environments by linking strategic spatial planning with evidence-based logistics governance recommendations.