What does a traffic jam in Atlanta have to do with segregation? Quite a lot.

Atlanta has some of the worst traffic in the United States. Drivers there average two hours each week mired in gridlock, hung up at countless spots, from the constantly clogged Georgia 400 to a complicated cluster of overpasses at Tom Moreland Interchange, better known as “Spaghetti Junction.” The Downtown Connector — a 12-to-14-lane mega highway that in theory connects the city’s north to its south — regularly has three-mile-long traffic jams that last four hours or more. Commuters might assume they’re stuck there because some city planner made a mistake, but the heavy congestion actually stems from great success. In Atlanta, as in dozens of cities across America, daily congestion is a direct consequence of a century-long effort to segregate the races.