It started on the drawing board two decades ago as an office park. Today it features townhouses and condos. And somewhere along the line, Reston Town Center became a national model as an attractive suburban place to live, work and play.

That model is about to be replicated across Northern Virginia.

Town centers are planned in Lorton near the Virginia Railway Express station and at Dulles Station near Route 28 and the Dulles Toll Road. Others are planned in Leesburg and Gainesville and near Potomac Mills. A mixed-use waterfront development that includes a conference center and nearly 4,000 homes has been proposed in eastern Prince William County.

Debbie Rosenstein of Rosenstein Research Associates, a Fairfax marketing firm, said town centers are appealing because they are upscale, modern versions of small-town main streets.

"It's a safe environment in the 'burbs, but they don't want to feel like they're on the edge of nowhere," Rosenstein said.

Town centers have been proposed in Merrifield, Falls Church and the area just southwest of the Springfield Mixing Bowl.

"Every master plan today usually includes a town center," said Dean Schwanke of the Urban Land Institute, a nonprofit research organization.

He said it is critical to design a town center with an appealing focal point such as a fountain or park. Town centers also need parking, and arranging it well is a major challenge.

"How do you make it not a big wall around the town center, and how do you make it not be ugly?" Schwanke said.

Falls Church is developing plans to convert one-story retail space at Routes 7 and 29 into a town center. Planner Gary Fuller said the aim is to build two block-long parks called Democracy Square and Freedom Square ahead of the 400 to 500 residential units and retail space that are planned.

"The idea is to build a public portion of it, and then the developers would be excited about building in that vicinity," Fuller said.

Falls Church is expected to absorb more residents as the region grows. Fuller said this type of construction helps expand the tax base to pay for services.

Done right, Schwanke said town centers might be a way to overcome resistance to growth as the region seeks to add 1.6 million jobs and 2 million residents by 2030.

"That's the way to solve the problem of density. It's not just density, it's cool," Schwanke said.

He said multiuse centers also are a better way to manage traffic, given that single-use projects such as office buildings and housing often create traffic jams at specific hours.

In some cases, residents might be able to park their cars for days at a time.

Katherine K. Hanley, former chairman of the Fairfax County Board of Supervisors, said she loves living in her Reston Town Center condo because she can walk to her job at the Greater Reston Arts Center.

Hanley, who serves on the Commonwealth Transportation Board, agrees that town centers can be a tool to increase density and affordable housing and to reduce vehicle trips. She welcomes the new neighbors she will have when residential units are added around Reston's growing town center.

"There are going to be a lot more people living at Market Center. I think that's exciting. It means it's sustainable," Hanley said.