In this paper, we analyze how the physical layout of cities affects innovation by influencing the organization of knowledge exchange. We exploit a novel data set covering all census block groups in the contiguous United States with information on innovation outcomes, street infrastructure, as well as population and workforce characteristics. To deal with concerns of omitted variable bias, we apply commuting zone fixed effects and construct instruments based on historic city planning. The results suggest that variation in street network density may explain regional innovation differentials beyond the traditional location externalities found in the literature.

中文翻译：

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将创新推向街头：微观地理、物理结构与创新

在本文中，我们分析了城市的物理布局如何通过影响知识交流的组织来影响创新。我们利用涵盖美国本土所有人口普查街区组的新数据集，提供有关创新成果、街道基础设施以及人口和劳动力特征的信息。为了解决遗漏变量偏差的问题，我们应用通勤区固定效应并构建基于历史城市规划的工具。结果表明，街道网络密度的变化可以解释超出文献中发现的传统位置外部性的区域创新差异。