There is something happening in many North American cities right now. We are starting to question the supremacy of zoning for only single-family homes.
This past summer, the state of Oregon passed policy requiring cities of 25,000 people or more to allow duplexes, triplexes, and fourplexes within their single-family home neighborhoods. Minneapolis is poised to do something similar with its Minneapolis 2040 plan (though it has been contentious). And, of course, here in Toronto we recently rolled out laneway suites all across the city. Small scale multi-family dwellings are also already permissible in some areas (though few are being built).
Some are calling this a YIMBY movement. But however you want to define it, it's an acknowledgement that, if the goal is to built up instead of out, perhaps it's time we look at the parts of our cities with the lowest population densities. I would also add that following my recent post on Paris vs. Vancouver, many seemed to gravitate (in the comments) toward the Parisian model -- even if it did result in over 50,000 people per square kilometer. Density, it would appear, is okay.
While positive, it remains to be seen whether these policy changes will result in a meaningful increase in housing supply. And a lot of that will come down to the details. As I have said before on the blog, the math can be challenging on these sorts of smaller projects, which is why you have smart people proposing things like an "inverse density" rule to help encourage more smaller scale development.
But as the saying goes, sometimes you need to crawl before you can walk. And, if nothing else, there's certainly symbolic value to what seems to be taking hold across North America right now.