Models of functional density of 10 cities

Maintaining street vitality—understood as the concentration of human activity—is a core urban priority, yet it remains difficult to predict. This paper explores street vitality in ten European cities using functional density, defined as the number of unique POI classes per street segment length, as a proxy. Using OpenStreetMap data and spatial lag regression with a log-transformed dependent variable, the analysis accounts for spatial dependencies while identifying drivers of functional density across and within cities. Results show morphological factors more consistently influence functional density than transport-related ones. High clustering in citywide models suggests a need for strategic planning, whereas weaker clustering in already vibrant streets highlights the importance of local street-level attributes. Long segments promote vitality at the city scale, while compact forms support dense areas. Commercial density boosts vitality citywide, while residential presence matters more in high-density streets. Transport infrastructure is relevant at the city level but plays a lesser role in already vibrant areas.