Most residents of the District of Columbia think of the Silver Line Metro project as being about bringing rail service to Dulles airport — something that's not going to happen for years to come. But in reality, airport connections are generally overrated as a mass transit priority. The most exciting thing about the Silver Line is something it's already accomplished — connecting the Tysons Corner business cluster to transit.

Tysons Corner is the original American "edge city." A kind of central business district without a downtown. An agglomeration of office towers and two huge shopping malls built around the convergence of several highways on the periphery of the Washington, DC metropolitan area. Even though it's far from the center of the region, Tysons Corner has become the #2 concentration of employment.

And the exciting idea that officials in Fairfax County had regarding the Silver Line was that they didn't just want to add park-and-ride Metro stations to an exurban sprawl are. They are trying to use the stations as levers to undertake a comprehensive urban retrofitting of the area — complete with new zoning for denser, less car-dependent development — in which an already built-up area will get even denser and become a brand new city.

Most observers' early impressions were that Tysons still has a long way to go as a haven of walkable urbanism. And based on my visit in late August, that's absolutely correct. Head out to the street exit from the Metro station and here's the view:

There's a branch of Firehook Bakery only about a block and a half from the Metro, but it's a long block and crossing the street is perilous — you're talking six lane roads full of drivers who don't think to look for pedestrians before making right turns on red. I nearly got run down twice:

The most pedestrian-friendly environment you'll find in the area is a skybridge connecting the Metro station to one of the malls:

And of course the two malls themselves, once you get inside, are great places to walk. Here's where Tysons gets interesting. In the United States, urban places are almost always old places — places where the built environment predates the automobile and the streetscape is oriented old mass transit lines, often ones that no longer exist. And when people think of new urban places, they often have in mind the idea of nostalgically recreating those old kind of places. But the parts of Tysons that work as a city aren't throwbacks at all. They more closely resemble an urban form you might see in Asia where urban density and newness aren't necessarily seen as enemies.

Hong Kong Island, for example, is a warren of shopping malls and towers and walkways over wide, divided roads.

If you cross the skybridge from the Tysons Corner Metro into the Tyson's I mall, you can then emerge from the mall into a little island of urbanism. They call it "The Plaza" and it's kind of like a public park, except it's privately owned and there's a mall cop watching out for miscreants.

Right now, the mall is the only entry point into the Plaza. But there's also a hotel right there that's scheduled to open soon and that will have its own separate connection to the Metro skybridge. Also under construction is an apartment tower that will be opening up a bit later and presumably have its own connections to the growing skybridge network. And there's much more development in the pipeline:

Whether the Tysons redevelopment ultimately succeeds or not will depend on those new projects and it may take a decade or two to fully assess. But it's already clear that if the urban retrofit does succeed, it's not going to generate the kind of low-rise boutique retro urbanism that's currently in style in gentrifying neighborhoods of many older American cities.

An urban Tysons, if it happens, will be not just a new city sitting at the intersection of the Beltway and the Metro. It will be a new kind of city — new to the United States, at least — that incorporates urbanism as a necessary workaround to expensive land and traffic congestion, rather than incorporating cars as a concession to modern technology.