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 <b>functional density</b>, 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 <b>morphological factors</b> 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 <b>local street-level attributes</b>. Long segments promote vitality at the city scale, while <b>compact forms</b> support dense areas. Commercial density boosts vitality citywide, while <b>residential presence</b> matters more in high-density streets. Transport infrastructure is relevant at the city level but plays a lesser role in already vibrant areas.