Planes, Trains, and Automobiles: What Drives Human-Made Light?

Abstract

This paper expands on our understanding of the lights-income relationship by linking the newest generation of nighttime satellite images derived from the Visible Infrared Imaging Radiometry Suite, VIIRS, to nationwide, panel data on population and income from 2012-2018 for both Brazil and the United States including 3,095 US counties, and 5,570 municipios. I leverage the quality and frequency of those data sources and the VIIRS lights images and confirm that nighttime light responds to changes in income when controlling for population effects. I find positive effects of GDP on light in both USA and Brazil, though light is less responsive to changes in GDP in Brazil than in the USA. Consistent with the literature, I discover nonlinearities in the form of decreasing marginal effects of GDP on nighttime light. This result holds across many specifications and is robust to sub-sample analysis and placebo tests. Leveraging the large sample size, I use regressions by centile of nighttime light to present a clear picture of the effects of GDP and population on nighttime light. In many cases, results are shown for the combined USA and Brazil samples, as well as the dis-aggregated samples. Finally, I use a between-county estimator to identify the effects of time-invariant infrastructure features on night-time light. Roads, rail, ports, airports, and border crossings I find contribute positively to nighttime light