Given that “redneck” and “hillbilly” remain the last acceptable stereotypes among polite society, it isn’t surprising that the stereotypical urban home of poor, recently rural whites remains an object of scorn. The mere mention of a trailer park conjures images of criminals in wifebeaters, moldy mattresses thrown awry, and Confederate flags. As with most social phenomena, there is a much more interesting reality behind this crass cliché. Trailer parks remain one of the last forms of housing in US cities provided by the market explicitly for low-income residents. Better still, they offer a working example of traditional urban design elements and private governance.

Any discussion of trailer parks should start with the fact that most forms of low-income housing have been criminalized in nearly every major US city. Beginning in the 1920s, urban policymakers and planners started banning what they deemed as low-quality housing, including boarding houses, residential hotels, and low-quality apartments.

Meanwhile, on the outer edges of many cities, urban policymakers undertook a policy of “mass eviction and demolition” of low-quality housing. Policymakers established bans on suburban shantytowns and self-built housing. In knocking out the bottom rung of urbanization, this ended the natural “filtering up” of cities as they expanded outward, replaced as we now know, by static subdivisions of middle-class, single-family houses. The Housing Act of 1937 formalized this war on “slums” at the federal level and by the 1960s much of the emergent low-income urbanism in and around many U.S. cities was eliminated.

In light of the United States’ century-long war on low-income housing, it’s something of a miracle that trailer parks survive. With an aftermarket trailer, trailer payments and park rent combined average around the remarkably low rents of $300 to $500. Even the typical new manufactured home, with combined trailer payments and park rent, costs around $700 to $1,000 a month. Both options offer a decent standard of living at far less than rents for apartments of comparable size in many cities. The savings with manufactured housing are a big part of the story: where the average manufactured house costs $64,000, the average site-built single-family house now costs $324,000. The savings don’t come out of shoddy construction either: manufactured homes are increasingly energy efficient, and their manufacturing process produces less waste than traditional site-built construction. With prosperous cities increasingly turning into playgrounds of the rich due to onerous housing supply restrictions, we shouldn’t take these startlingly affordable rents lightly.

Trailer parks are not only cheap due to manufacturing; they’re also cheap thanks to their surprising exemption from most conventional land-use controls. Most cities zone very little space for trailer parks—presumably a reflection of the general bias against low-income housing. But where they exist, they are often subject to uniquely liberal land-use regulation, with minimal setbacks, fewer parking requirements, and tiny minimum lot sizes. The result is that many trailer parks have relatively high population densities. The New World Economics blog explains: