The way to have abundant affordable housing is to have abundant housing. That means making it easy to add residential units. I want to propose a simple, if radical policy that can guarantee abundant affordable housing: state or federal laws requiring mandatory permitting of trailer parks that meet a few basic standards.

There is little worry that trailer parks will spring up in a long-lasting way in totally inappropriate places, because any place land is worth too much, a trailer park operator can’t earn a profit. On the other hand, a trailer park gives a developer a nice threat point to persuade a neighborhood to allow more appropriate (and profitable) high-density housing.

Where land is cheaper—perhaps because of noise, or simply by being further out from the city center, a trailer park might make a lot of sense.

As “Do Trailer Parks and Mobile Homes Have a Future As Affordable Housing?” suggests, there is also no reason a trailer park can’t stay a trailer park but go upscale. The legal definition would be that it would have to be the locational home to manufactured housing—at least in the sense that large pieces were made in a factory. This would give an extra boost to home manufacturing, which is desperately needed. As I discuss in “Why Housing is So Expensive,” construction has shown almost no productivity growth by the usual measures. I suspect a lot of that is because most homes don’t have large pieces made in factories. It is hard to improve production if it doesn’t have some degree of centralization and standardization—or at least modularity. The bigger the percentage of homes that have large manufactured pieces, the faster total factor productivity in housing production will improve.

Note that with a state or federal law requiring mandatory permitting of trailer parks that meet a few basic standards you can get affordable housing in most places without subsidies. It is market rate affordable housing—which should be considered the Holy Grail, while subsidized affordable housing is typically just tokenism. I’d like to suggest one place to put the budgetary savings from not subsidizing housing: instead, subsidize convenient, frequent bus service to any sufficiently large concentration of trailers. This helps make sure that the affordable trailer-park housing will work for people. The residents have to be able to get to their jobs, after all—and those with low income often own unreliable cars or no car. (Note that trailer parks have full-scale house rentals as well as people who own the house and only pay plot rent and home-owner’s association fees.)

Also, nearby current residents shouldn’t have to suffer from an increase in crime when a trailer park is created next door. And those in the trailer parks themselves shouldn’t have to suffer with high crime rates, whether many felonies or many small misdemeanors. If this is a genuine danger, we need to be brutally honest about it—and if a genuine danger, it is a legitimate concern. Thus, in addition to subsidizing good bus service to new trailer parks, I suggest state and federal subsidies for extra police to police the new trailer parks and surrounding areas.

Let me give you a challenge: when you hear someone talking about affordable housing without offering a radical scheme that moves at least 10% toward what I am saying, you can know they aren’t serious about affordable housing beyond tokenism. Let’s get real about affordable housing. It is a huge part of the typical individual’s or families budget. So the poor get much less poor when housing gets cheaper. And the rich or middle class whose property values suffer some because the scarcity value is less—or because now they can’t have as much residential segregation can afford the hit.

By the way, people often talk about “systemic racism” without pointing to what it is actually made of. Barriers to residential construction are a big part of structural racism by perpetuating residential segregation that helps the rich and middle class to not care about the poor because they are out of sight, out of mind, and deprives talented children from poor families of mentors they desperately need. (If the poor living near the rich and sending their kids to the local schools makes the rich hate the poor more, rather than caring about them more, then we have worse problems.)