Depending on who you ask, Mexico City is either the most or the 12th most congested city in the world. Either way: No fun! Residents who drive lose up to 227 hours each year to traffic jams. That's more than nine days in aggregate—enough time to watch Game of Thrones all the way through. Thrice.

So you might be surprised to learn that Mexico City just made it easier for real estate developers to avoid building parking. Mayor Miguel Ángel Mancera Espinosa this month announced a new policy that limits how many parking spaces builders can build. He hopes to spur development, which sounds counterintuitive. Without parking spaces, where will commuters rest their rides?

But it turns out sprawling parking lots and looming garages can actually create more traffic and make housing less affordable and city streets more difficult to navigate. By limiting the growth of its parking infrastructure, the largest city in North America thinks it can return some balance to its urban ecosystem. Listen up, United States: Your southerly neighbors might be on to something.

Parking Versus Housing

Mexico City, population 9 million, is a typical booming, developed city. Much like its crowded American neighbors—San Francisco, New York, Miami, Houston—newcomers have rushed to live in its center, increasing rental prices on the city's limited housing stock. “Rich people flew out of these areas and now they’re coming back,” says Rodrigo García Reséndiz, a Mexico City native and urban planner who works for the planning firm Alta in Los Angeles. “So the people who are usually there, the low-income people, are now being pushed out.”

The response to overcrowding would generally be: Build, build, build! That’s happening in Mexico City, albeit to a small degree. It's building just 12 percent of the homes it needs to accommodate growth. Worse, many recently built homes are for high-income earners, not low-income ones.

Parking exacerbates this imbalance. The city's old rules said developers had to build a certain number of parking spots for every square foot they constructed. And you know where displaced people can't live? Parking spots. According to a report published by the Institute for Transportation and Development Policy, 251 Mexico City real estate projects dedicated 42 percent of construction between 2009 and 2013—about 172 million square feet—to parking, more than 250,000 spaces in all. That’s an awful lot of unbuilt bedrooms. The kicker: The cost of that infrastructure, about $10,000 per parking space, gets passed on to renters, whether they own a car or not. (About 70 percent of Mexico City residents don't.)

That's why cities the world over have gotten creative about fighting parking. London got rid of parking minimum regulations in 2004, and the number of parking spaces fell by 40 percent. The Obama administration recommended pulling a similar move in housing development recommendations released last year. San Francisco uses a points system, allowing developers to build parking spots if they’ve also shelled out for transportation alternatives: shuttle services, car-sharing memberships for everyone in the building, a bicycle fleet in the basement.

But real estate developers (and the bankers who finance them) have to buy into these schemes, too. Mexico City's say they're on board. Before the regulation changed last week, builders constantly complained that onerous parking regulations made it harder for them to build the projects they wanted, says Andrés Sañudo, an independent transportation consultant who studies parking regulations in Mexico City. Now they have an opportunity to prove they want to build more housing.

A Parking Experiment

The interesting thing about this plan? Mexico City isn't quite sure what its citizens want, parking-wise. Before the mayor changed the regulation, parking was always just ... there. “It was impossible to see what the real market for parking was,” Sañudo says. “Everyone was providing what the regulation said without any regard of location or any other characteristics.” This is what makes the city's plan a bit of an experiment. Hell, no one knows how much parking Mexico City residents have right now.