Next Stop, Tysons

"If I live where I work, I'm not going to have that kind of problem," Connolly said. "The problem at Tysons is peak congestion."

Ewing disagreed: "Common sense dictates we're at gridlock. If you add 3.5 million square feet, you're not going to improve that."

Skeptics argue that the high-density approach worked in Arlington for several reasons: It is a well-defined corridor with multiple entry points from the surrounding grid of streets; its proximity to the District makes its apartment towers attractive to young people; and the hodgepodge of car dealerships and low-slung shopping strips that predated the start of redevelopment in the 1970s was insubstantial enough that it could be displaced with something else.

Tysons, on the other hand, is a sprawling, 1,700-acre area that lacks a street grid and is both broken up and sealed off by several highways, including the Capital Beltway, the Dulles Toll Road and Route 7, skeptics note. Although it is scheduled to get Metro in 2012, it is farther from the District and thus less appealing to many potential younger residents. And although some of its office towers are nearing the end of their lifespan, much of what is there today, including the two big malls at its center, is unlikely to be replaced anytime soon, precluding a total overhaul like Arlington's.

Among the skeptics is Robert E. Simon, founder of Reston and its Town Center. He agrees with Fairfax's plans to focus growth near transit but said it was unrealistic that Tysons would ever be as cohesive and pedestrian-friendly as the Rosslyn-Ballston corridor, because of its sheer size and the way it's "so chopped up because of the enormous superhighways."

"It isn't conceivable that it will ever work, because people will not walk from one part of it to another. I can conceive of them finding one place, a pleasant mall or plaza-like place, but as far as converting the whole thing into something good, I can't see that," Simon said.

But others say such doubts betray a lack of imagination. Although Tysons covers a big area, optimists say, the county can certainly hope to transform at least the slice of it that will be within walking distance of the four stations planned along Route 7 and 123 -- a stretch that is slightly shorter than the Rosslyn-Ballston corridor.

If the county focuses new apartment buildings in those areas, implements a street grid and invests in a strong bus system to feed into the rail stations, a transformation is possible, said Patty Nicoson, a former Arlington transportation planner who runs a nonprofit group advocating for the rail extension to Tysons and Dulles International Airport. It's no harder to envision that, she said, than it was to imagine 30 years ago that Arlington would be what it is today.

"If you take the longer view, you can see that as this place develops, people are going to embrace a vision, too," she said. "You need to have faith."

Stewart Schwartz, executive director of the Coalition for Smarter Growth, agreed that Tysons can be transformed, but only if the planned Metro line is run underground instead of on an elevated track, as is planned. He compared the importance of that decision to Arlington's choice of locating the Orange Line beneath Wilson Boulevard instead of up Interstate 66, even though it cost much more do to so.

Also necessary, he said, is that the state drop its plans to turn Route 123 into an expressway and instead make it into a boulevard, as is planned for Route 7. This would improve pedestrian access to Tysons Corner Center and free up the chunk of land taken up by the interchange of Routes 7 and 123.

Following this debate from nearby, current and former Arlington officials say they wish officials in Fairfax and other suburbs well, but they caution that duplicating the model won't be easy. It took Arlington decades, they said, to draw up plans, win support from nearby residents and then attract the kind of development they were hoping for.

Winning local support was achieved, officials said, only after countless meetings and pledges that Arlington would stick to a "bull's-eye" approach, limiting the tallest buildings to a quarter-mile radius from rail stations and not encroaching on neighborhoods. To keep up support over time, the county instituted parking limits and traffic-calming methods on nearby streets.

Employees and residents in the corridor are encouraged to stay out of their cars through parking limits, transit subsidies, a county bus system, bike paths and pedestrian-friendly street designs. The county has the advantage of having control over the design of its secondary streets, an authority that in most Virginia counties is held by the state.

"It's not just one policy but a whole series of things," said Dennis Leach, the county's transportation chief. "This is not something you do overnight. Arlington's been at this 30 years, and not everything's perfect. We have a lot more to do."

The results are the envy of transportation planners worldwide. After declining in the 1970s, Arlington's population has expanded by a third since 1980 to nearly 200,000, with much of the growth in the corridor. Yet the county has seen only modest increases in traffic on local streets. Metro ridership, meanwhile, is surging, with a 36 percent increase in the county in the past decade. In the corridor, only 40 percent of residents drive alone to work, compared with 70 percent in other area suburbs including Fairfax and Montgomery, and homes in the corridor average one car each, compared with 1.75 in other suburbs.

Few expect that Fairfax can match those figures, but some argue that the county should try anyway. Christopher Leinberger, a land-use expert at the Brookings Institution, said that in an age of global warming and dwindling resources, suburbs such as Fairfax have no choice but to adopt Arlington's approach.

"High-density, transit-oriented urbanity is one of the most important things we have to achieve," he said. "It's not too late for Tysons. Having said that, Tysons and Tysons-like places pose problems we don't yet know how to solve."