论文标题
离网格...然后又回来了？美国街头网络计划和设计的最新演变
Off the Grid... and Back Again? The Recent Evolution of American Street Network Planning and Design
论文作者
论文摘要
这项形态学研究确定和衡量了美国街头网络设计的最新趋势。从历史上看，正交街道网格提供了相互连接和密度，研究人员将其视为减少车辆旅行和排放以及增加道路安全和体育锻炼的重要因素。在20世纪，随着城市化围绕汽车依赖性，城市化，城市化，密度和连通性的下降以及城市形式的紧凑，密度和连通性的下降。但是，对整个美国社区的全面经验趋势的了解鲜为人知，尤其是近年来。这项研究使用公共和开放数据来检查整个美国各地的街道网络。它开发了理论和测量框架，用于此处定义为网络的街道网络的质量。它衡量了从1940年到1990年代的网格，定向顺序，直度，四向相交和交叉密度的下降，而死端和块长度则增加。但是，自2000年以来，这些趋势已经反弹，转向历史设计模式。然而，尽管有这种反弹，但在控制地形和建筑环境因素时，所有数十年后的几十年都与1940年前的网格息息相关。较高的网格与较少的汽车所有权有关 - 它本身与行驶的车辆公里和温室气体排放有着良好的关系 - 同时控制着密度，家庭和家庭规模，收入，就业机会，靠近工作，街头网络谷物和本地地形。类似网格的街道网络为从业者提供了遏制汽车依赖和排放的重要工具。一旦建立，街道模式决定了几个世纪以来的城市空间结构，因此积极的计划至关重要。
This morphological study identifies and measures recent nationwide trends in American street network design. Historically, orthogonal street grids provided the interconnectivity and density that researchers identify as important factors for reducing vehicular travel and emissions and increasing road safety and physical activity. During the 20th century, griddedness declined in planning practice alongside declines in urban form compactness, density, and connectivity as urbanization sprawled around automobile dependence. But less is known about comprehensive empirical trends across US neighborhoods, especially in recent years. This study uses public and open data to examine tract-level street networks across the entire US. It develops theoretical and measurement frameworks for a quality of street networks defined here as griddedness. It measures how griddedness, orientation order, straightness, 4-way intersections, and intersection density declined from 1940 through the 1990s while dead-ends and block lengths increased. However, since 2000, these trends have rebounded, shifting back toward historical design patterns. Yet, despite this rebound, when controlling for topography and built environment factors all decades post-1939 are associated with lower griddedness than pre-1940. Higher griddedness is associated with less car ownership - which itself has a well-established relationship with vehicle kilometers traveled and greenhouse gas emissions - while controlling for density, home and household size, income, jobs proximity, street network grain, and local topography. Interconnected grid-like street networks offer practitioners an important tool for curbing car dependence and emissions. Once established, street patterns determine urban spatial structure for centuries, so proactive planning is essential.
