For surface transportation, we create a spatial surrogate using a weighted average of roadway lengths of OpenStreetMap (OSM) roadways in each CEDS grid cell. We use the following weighted average of OSM roadway types: 36% motorways, 21% trunk roads, 18% primary roads, 9% secondary roads, 1% tertiary, unclassified, and service roads, and 14% residential roads. This weighting is derived from U.S. data on urban road uses (US DOT FHA, 2017); the taxonomy of roadway types is described in Table (OSM, 2019).