We present a global time series of street-network sprawl-that is, sprawl as measured through the local connectivity of the street network. Using high-resolution data from OpenStreetMap and a satellite-derived time series of urbanization, we compute and validate changes over time in multidimensional street connectivity measures based on graph-theoretic and geographic concepts. We report on global, national, and city-level trends since 1975 in the street-network disconnectedness index (SNDi), based on every mapped node and edge in the world. Streets in new developments in 90% of the 134 most populous countries have become less connected since 1975, while just 29% show an improving trend since 2000. The same period saw a near doubling in the relative frequency of a street-network type characterized by high circuity, typical of gated communities. We identify persistence in street-network sprawl, indicative of path-dependent processes. Specifically, cities and countries with low connectivity in recent years also had relatively low preexisting connectivity in our earliest time period. We discuss implications for policy intervention in road building in new and expanding cities as a top priority for sustainable urban development.

中文翻译：

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全球城市街道网络的蔓延趋势。

我们提出了街道网络蔓延的全球时间序列，即通过街道网络的本地连接性度量的蔓延。使用来自OpenStreetMap的高分辨率数据和卫星衍生的城市化时间序列，我们基于图论和地理概念计算和验证多维街道连通性度量随时间的变化。我们根据世界上每个映射的节点和边缘，报告了1975年以来全球，国家和城市级趋势的街道网络不连通性指数（SNDi）。自1975年以来，在134个人口最多的国家中，有90％的新开发项目中的街道之间的联系减少，而自2000年以来，只有29％的街道显示出改善的趋势。同一时期，以以下特征为特征的街道网络的相对频率几乎翻了一番：高电路，典型的封闭式社区。我们确定了在街道网络蔓延中的持久性，表明了路径依赖的过程。具体而言，近年来连通性较低的城市和国家在我们最早的时期内也具有相对较低的既有连通性。我们讨论在新兴城市和扩展城市道路建设中政策干预的意义，将其作为可持续城市发展的重中之重。