Apparently, a major threat to the District looms on the horizon. “This is a very dangerous proposal,” the warning recently went out. “We think it threatens the future of Washington.”

Terrorists? Hurricanes? Flooding from climate change? Sequestration? Meteors? Nonexistent snow? A paucity of decent bagel shops?

No, the threat is that the District might get out of the business of micromanaging the size of apartment-building parking garages. Run for cover!

The group warning of this looming disaster? An organization that you might give money to yet disagree entirely with its often extreme lobbying agenda: AAA. The dire-sounding words above were spoken by AAA-Mid-Atlantic spokesman Lon Anderson in an interview with WAMU.

What’s happening is that the District — especially its inner neighborhoods — has evolved from a place suffering depopulation and desperate to attract suburban commuters to maintain downtown property values into one of the fastest-growing and most-desirable cities in America.

That means, first, more residents. More residents means more patrons for businesses in retail corridors. It also can mean more traffic — but not as much as you’d think, because the residents of dense urban neighborhoods drive at lower rates than those in the region as a whole.

The Metropolitan Washington Council of Governments examined travel patterns for residents in the Logan Circle, eastern Dupont Circle, U Street and Shaw neighborhoods. There, residents ride transit more often than they drive, and they own more bicycles than cars.

The threat from this to AAA’s business model is clear. But for the rest of the region, it’s good news that more people are choosing to buy homes, raise families, retire or invest in walkable urban areas.

However, there is a genuine threat. The threat is that, though more people want to live near their jobs or transit and in walkable neighborhoods, they won’t all be able to. The supply of housing in such places isn’t expanding quickly enough.

According to the Census Bureau, the median price of an owner-occupied home in the District is more than twice the national average. That’s good news for past investors, but it’s a problem for aspiring middle-class homeowners. And it’s spurred the redevelopment of cheap rental properties into luxury condos — good news for the city’s tax base but bad news for the poor.

Having the government mandate a set amount of parking diminishes our future in two ways. First, the parking facilities take up space and require workers and construction materials to build. This land and labor ultimately must be paid for by renters or buyers. Paying more for a useful amenity like a parking space is fine, but it’s perverse to be required to pay for a parking space you don’t need because a developer had to include it to get permission to build your home.

Second, the geography or geology of some lots simply isn’t always amenable to including as much parking as the city’s zoning code requires. That either leads to less homebuilding or to costly and contentious variance applications.

We see danger in the District’s future, too, but it’s the opposite danger from what Anderson sees. The real danger is that large numbers of people will be excluded from the kinds of communities they want to be a part of.

The real danger is that the District’s hybrid federal-local Zoning Commission might get cold feet after hearing such hysteria and decline to make even a modest change to existing parking rules.

The real danger is that D.C. Council Chairman Phil Mendelson, who has oversight of the Office of Planning, which is developing the zoning update proposals,” might bow to these fears and try to delay change. The zoning update has already been five years in the making; each year we wait, more housing opportunities are lost.

A city without mandatory minimum parking regulations is not a city without parking. Cars are useful, which is exactly why many people pay a lot of money to own one. Parking spaces are also useful, and whatever rules the city adopts, developers will surely choose to provide some — just as many homes have granite countertops, hardwood floors or other desirable extras.

But land is scarce and expensive in our growing metropolis, and underground parking is extremely expensive to build, often costing $30,000 to 50,000 per space. Balancing the supply of parking spaces with actual demand for them is exactly the sort of thing markets are good at. No part of the city truly needs parking minimums, and the current proposal to lift them in the dense transit-adjacent neighborhoods is an important step in the right direction.

Less subsidy to car ownership is a threat to some entrenched interests. But it’s also a simple and low-cost way to address the pressing threat that the city’s most desirable neighborhoods won’t be able to accommodate the people who want to live in them.

David Alpert is editor of the blog Greater Greater Washington and Greater Greater Education. Matthew Yglesias is business and economics correspondent at Slate.