Objectives

For more than one hundred years, street lighting has been one of the most ubiquitous capital investments in public safety. Prior research on street lighting is largely limited to ecological studies of very small geographic areas, creating substantial challenges with respect to both causal identification and statistical power. We address limitations of the prior literature by studying a natural experiment created by short-term disruptions to municipal street lighting.

Methods

We leverage a natural experiment created by the differential timing of the repair of nearly 300,000 street light outages in Chicago. By conditioning on street segment fixed effects and focusing on a short window of time around the repair of a street light outage, we can credibly rule out confounding factors due to area-specific time trends as well as street segment-level correlates of crime.

Results

We find that outdoor nighttime crimes change very little on street segments affected by street light outages, but that outages cause crime to spill over to nearby street segments. Effects are largest for robberies and motor vehicle theft.

Conclusions

Despite strong environmental and social characteristics that tend to tie crime to place, we observe that street light outages are sufficiently salient to disrupt longstanding patterns. While the impact of localized street light outages can reverberate throughout a community, the findings imply that improvements in lighting can be defeated by the displacement of crime to adjacent spaces and therefore do not necessarily suggest that localized investments in municipal street lighting will yield a large public safety dividend.

中文翻译：

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路灯断电、公共安全和犯罪活动

目标

一百多年来，街道照明一直是公共安全领域最普遍的资本投资之一。先前对街道照明的研究主要限于非常小的地理区域的生态研究，这在因果识别和统计能力方面造成了巨大的挑战。我们通过研究由市政街道照明的短期中断造成的自然实验来解决先前文献的局限性。

方法

我们利用芝加哥近 300,000 处路灯故障修复的不同时间创建的自然实验。通过调节街道段固定效应并关注修复路灯故障的短时间窗口，我们可以可靠地排除由于特定区域时间趋势以及街道段级别的犯罪相关性引起的混杂因素。

结果

我们发现，在受路灯中断影响的街道段上，户外夜间犯罪变化很小，但中断会导致犯罪蔓延到附近的街道段。抢劫和机动车盗窃的影响最大。

结论

尽管强烈的环境和社会特征倾向于将犯罪与地点联系起来，但我们观察到，路灯中断足以破坏长期存在的模式。虽然局部路灯断电的影响会在整个社区产生反响，但研究结果表明，犯罪活动转移到相邻空间可能会阻碍照明的改善，因此并不一定表明对市政路灯的局部投资会产生大量公众安全红利。