Detroit spent the last decade spiraling into bankruptcy, while Atlanta spent it growing like mad. But the two cities have something in common: "Both are places where the American dream seems to be dying," writes Paul Krugman at the New York Times. Social mobility is low in both cities—meaning the poor are staying poor. Why? Well, a new study suggests that it might be because they're just too spread out. "Sprawl may be killing Horatio Alger."
The study found that social mobility was correlated with how far apart various classes lived from each other. "In Atlanta, poor and rich neighborhoods are far apart because, basically, everything is far apart; Atlanta is the Sultan of Sprawl," Krugman writes. "Disadvantaged workers often find themselves stranded; there may be jobs available somewhere, but they literally can't get there." We need to build smarter, more compact population centers that let families get by without multiple cars. Click for Krugman's full column. (Read more Paul Krugman stories.)