When Virginia began the massive reconstruction of the notorious Springfield Mixing Bowl, the list of concerns among neighbors could hardly be overstated.

"We thought it would be disruptive, there would be street closures, it would be impossible to navigate our community, we'd get weird cut-through traffic and it would affect small business and put people out of business," said Tawny Hammond, president of the Springfield Civic Association.

But a funny thing happened on the way to gridlock: Something went right. Looking back five years after construction began, some residents and officials said yesterday that state planners had overcome initial problems and that the $700 million project is proceeding smoothly. "It's been managed really well. I am honest-to-goodness amazed," said Hammond, who credited the widening of nearby roads for easing the effect on Springfield neighborhoods.

And so it was that when residents assembled yesterday for a "Springfield community celebration," among the things they were celebrating -- or at least expressing relief over -- was that their community has been relatively unaffected by the jackhammers and cranes still laboring nearby.

Hammond organized the festival at the marina at Lake Accotink Park in Springfield, which she manages. It resembled a large block party, with live music, children's games and a fireworks show last night. "We're celebrating the end of summer, back to school and just celebrating the community," Hammond said.

As more than 150 people milled around, among the souvenir stands was a Virginia Department of Transportation booth, where an employee passed out brochures titled "Springfield Interchange Improvement Project: Worth the Effort" and blue funnels promoting the same message.

Rita Alexander, who lives near the construction zone, accepted a funnel and said she thinks the project "has gone very smoothly." She credited VDOT and local officials with informing neighbors about each phase.

Jennifer Drake, who moved into the area with her family three years ago from Wyoming, agreed. "When we first got here, the whole Mixing Bowl area was a mess," she said. "It still has a long way to go, but it's steadily getting better."

Springfield resident John Smith, sitting at a concession stand, said he thinks the project "can only be a good thing" but wondered: "Wasn't it over budget?"

Indeed, costs for the effort to address the traffic chaos and high accident rate where the Capital Beltway, Interstates 95 and 395 and Old Keene Mill and Franconia roads cross and merge have escalated dramatically since the initial $220 million price tag in 1994. A federal report in 2002 said projected costs were approaching $1 billion because of poor oversight.

But VDOT officials insisted that the project is on schedule for completion by the end of 2007 within its revised $700 million budget. And several recent steps have proved successful, such as Wednesday's opening of a second exit lane on an I-95 flyover at the Mixing Bowl, months ahead of schedule.

Fairfax County Supervisor T. Dana Kaufmann (D-Lee), who represents much of the construction area, said the project is bringing in new business. "Instead of destroying Springfield, it has helped position us for a brighter future," he said.

Richie Fruchterman, 7, of Annandale reaches for the top of the climbing wall.Clockwise from left, Milo, Sadie and Rusty get plenty of attention at the celebration.