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

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 3,104 US counties, and 5,570 munic\'ipios. I leverage the quality and frequency of those data sources and the VIIRS lights images to decompose the links between population changes, GDP changes, and nighttime lights changes at the county and munic\'ipio level. I find decreasing marginal effects of GDP on nighttime light as well as decreasing marginal effects of population on nighttime light, a result which holds across many specifications and that is robust to sub-sample analysis and placebo tests. Interactions among controls also appear to be present. Using sub-sample analysis, I also find that nighttime light does a poor job of capturing less-wealthy areas. 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 to be strong contributors to increases in light.