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.

维持街道活力——其定义为人类活动的集聚程度——是城市核心发展目标之一，但该指标仍难以精准预测。本文以**功能密度（functional density）**作为代理变量，探究欧洲十座城市的街道活力状况；功能密度指的是每段街道街区内的独特兴趣点（Point of Interest，POI）类别数量。本研究借助开放街道地图（OpenStreetMap）数据，采用引入对数变换因变量（log-transformed dependent variable）的空间滞后回归（spatial lag regression）模型，在控制空间相关性的同时，识别了城市间及城市内部功能密度的驱动因子。研究结果显示，**形态因素（morphological factors）**对功能密度的影响相较交通相关因素更为稳定一致。全域模型中呈现的高度集聚特征表明，需开展战略性城市规划；而在已然富有活力的街道中集聚度较低，则凸显出**局部街道级属性（local street-level attributes）**的重要性。较长的街道街区在城市尺度上可提升街道活力，而**紧凑形态（compact forms）**则有助于强化高密度区域的活力。商业密度可全域性地提升街道活力，而**居住属性（residential presence）**在高密度街道中的影响更为显著。交通基础设施在城市尺度上与街道活力相关，但在已然活力充沛的区域中其作用相对有限。