The so-called “donut” hypothesis argues that cities contain concentric rings of poverty and wealth: the rich live in the (presumably renewed) city center and in the outer suburbs, while the poor accumulate in between.
Radical Cartography has attempted to verify this premise, with mixed results:
This does seem to have some validity in older cities like Boston, New York, Philadelphia, or Chicago, but in newer cities it is not the case. Instead of donuts, one finds “wedges” of wealth occupying a continuous pie-slice from the center to the periphery.
This certainly seems true of Phoenix, where all the money seems to have moved northeast. St Louis is similar: head west, about halfway between I-44 and I-70, and once you clear the line between city and county, there’s your wedge.
And there’s this:
Just from visual inspection, it also seems that poverty donuts all tend to have about a five-mile radius, regardless of the size of the city. Perhaps this is the practical limit for commuting without a car?
Makes sense. I’m thinking also that the earliest employers to flee the center city might have stayed within that same radius, in an effort to retain as many personnel as they could. They certainly wouldn’t do that today.
(Via New Geography.)