Former Chicago resident here: the variable they need to control for is average speed along the routes with red lights. Because 1) Chicago is one of the most seg

Former Chicago resident here: the variable they need to control for is average speed along the routes with red lights. Because 1) Chicago is one of the most segregated cities in America and 2) the street traffic on the predominantly white Northside was pretty terrible. Picture 2 - 4 lane streets that are backed up such that it’s hard to ever get up to speed. Meanwhile, the main roads on the South and West side are much more open. So it’s much easier to get up to speed and try to make the light. I like ProPublica but this isn’t up to their usual standard of analysis.