US sprawl is not a market outcome.

A discussion is going around the internet about John Stossel's "libertarian" piece on the virtues of sprawl. John Norquist, on the other hand, labels sprawl a "communist plot," and Matthew Yglesias notes how bulk zoning requirements promote sprawl.

A point John likes to make is sprawl is at least in part the result of government housing finance policy. The New York Times this morning:

I.R.S. requirement keeps the agency from acquiring mortgages made in buildings where more than 20 percent of the square footage is commercial — space that is used for, say, a hotel or a doctor’s office.

Mixed use development is not going to happen if it can't get financed. Most of Paris, London, large swaths of San Francisco (i.e., some of our best urban places) would not qualify for US housing finance rules. And of course, single use zoning would ban them all.

But most insidious is that zoning is used as a tool to keep low-to-moderate income people out of suburbs. The town next door to mine--San Marino--has zoning requirements so onerous that it is not possible to build small housing there. Even my town, Pasadena, which at least has a bunch of apartments, prevents construction of granny flats on lots smaller than 15,000 square feet. These rules keep out the poor, which reduces expenditures on social services, which makes property values higher, which keeps out the poor, which...

Of course poor people must live somewhere, and so they live in cities with old housing stock that was built before the era of stringent zoning. So cities with old housing stock are placed at a fiscal disadvantage, which induces people with means to leave, which puts them at a greater fiscal disadvantage, etc....