经济距离塑造美国109个城市的城市流动性
Economic Distance Structures Urban Mobility in 109 U.S. Cities
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中文总结 AI 辅助
该研究以美国109个城市为对象，提出“经济距离”概念，发现日常流动的0.25分位数经济半径边界，揭示其不对称性及对城市不平等的塑造作用，为跨阶层互动干预提供理论支撑。
中文摘要 AI 辅助
城市流动性有望促进社会融合，但日常流动却受到社会经济等级制度的系统性约束。本文引入“经济距离”——即起点与终点之间的连续收入差距——作为统一视角，分析美国109个城市的大规模流动性记录，以揭示城市流动的结构。我们识别出一个普遍的结构边界：流动在0.25分位数的狭窄经济距离内高度集中，定义了日常流动的有效“经济半径”。该边界呈现显著不对称性：向上流动在各城市面临统一的结构上限，而向下流动则驱动跨城市异质性。从机制上看，该边界在物理上由中观尺度的居住聚类锚定，但会被独立的经济距离摩擦进一步收紧，这一点通过引力模型得到验证。这些相互作用产生了四种不同的流动模式，其中“富裕受限”系统表现出最强的分层。这些发现确立了经济距离是塑造城市不平等的基本、不对称且多尺度的过滤器，为针对跨阶层互动结构性障碍的干预措施提供了新的理论依据。
英文摘要
Urban mobility promises social integration, yet daily movement is systematically constrained by socioeconomic hierarchies. Introducing "economic distance"--the continuous income gap between origin and destination--as a unified lens, we analyze large-scale mobility records across 109 U.S. cities to reveal how urban flows are structured. We identify a universal structural boundary: flows concentrate intensely within a narrow economic distance of 0.25 quantiles, defining the effective "economic radius" of routine mobility. This boundary exhibits profound asymmetry; upward mobility faces a uniform structural ceiling across cities, whereas downward mobility drives cross-city heterogeneity. Mechanistically, the boundary is physically anchored by meso-scale residential clustering but is further tightened by an independent economic-distance friction, validated via gravity modeling. These interactions yield four distinct mobility regimes, with "affluent-confined" systems exhibiting the strongest stratification. These findings establish economic distance as a fundamental, asymmetric, and multi-scale filter shaping urban inequality, offering new theoretical grounds for interventions targeting structural barriers to cross-class interaction.
