Loudoun County's often caustic debate over how to manage the fiscal and traffic challenges of growth came around this week to the roundabout -- a circular, signal-less, traffic-channeling setup that is popular in Europe and will make an appearance at intersections here in the next few years.

At a meeting Monday of the Board of Supervisors' transportation and land-use committee, officials renewed discussion on the ongoing traffic-calming project on Route 50.

Backers say the project will prevent speeding on the country road that is a main commuter route but also serves as a Main Street for small communities. Critics say the plan is ultimately intended to stymie construction in rural areas.

The project is to stretch along 20 miles of Route 50, starting east of Route 15 and extending through Aldie, Middleburg and Upperville, in Fauquier County. It has received about $30 million in federal financing and about $9 million from the state. Sen. John W. Warner (R-Va.) and Rep. Frank R.Wolf (R-Va.) have been key supporters of the plan.

Construction in Upperville is expected to begin next year.

The debate Monday focused on a series of roundabouts surrounding the intersection of Route 50 and Route 15 that are part of the plan. Construction on the roundabouts is scheduled to begin in 2007, according to the Virginia Department of Transportation, and they will replace the signal light that now controls traffic at the crossroads, known as Gilberts Corner.

Any major changes to the already-funded and approved plan, however, are highly unlikely, if not impossible, county officials said. Nonethetheless, opponents have sought a forum for their objections.

Ken Reid, a Leesburg resident and consultant who was hired by a Middleburg group to oppose the project, questioned federal spending on the effort and argued that the project was intended to "privatize Route 50" by making it less efficient for commuters. He instead proposes an interchange at Gilberts Corner, bypasses around communities and a major new highway, perhaps funded by tolls. He also critiqued the design.

"It's a real funny configuration. Usually, you'll just see one of those things. You won't see two or three or four," Reid said.

In addition to roundabouts south and east of Gilberts Corner, the plan places a large roundabout at the crossroads itself.

Supervisor D.M. "Mick" Staton Jr. (R-Sugarland Run) expressed skepticism about the overall approach.

"We're building a solution based on the assumption that it will remain two lanes" for the foreseeable future, he said. "I don't want to see this project . . . driving the train on our long-term plans."

But Supervisor Jim G. Burton (I-Blue Ridge), who is on a committee of officials and residents overseeing the Route 50 effort, said the roundabouts are a cost-effective tool that will speed traffic through Gilberts Corner and will be built with a sensitivity to the historic character of one of the most beautiful parts of the Washington area.

Drivers coming through Gilberts Corner experience heavy traffic, and wait times are increasing. The average delay during the morning rush hour is expected to be 12 minutes by 2010, according to an analysis presented by Burton.

The network of roundabouts, and an access road, will allow traffic heading north on Route 15 to avoid the main intersection. Other features of the plan will allow traffic to move more smoothly overall, Burton said. Delays by 2010 will be less than a minute, according to the analysis.

"We are providing an extremely large reduction in congestion delays and improving safety. I think that's a good investment," Burton said, adding that the design was developed by some of the world's top experts on roundabouts. "It is a short-term solution that was affordable."

Burton noted that the plan for Route 50 emerged through public meetings in the 1990s in the aftermath of community opposition to a proposal to widen the thoroughfare and build bypasses around such communities as Middleburg. There was no money for such a project then and there isn't now, Burton said.

Jim Rich, a regional Republican Party official and co-chairman of the traffic-calming committee, said building roundabouts is the best solution. Building bypasses would be too expensive, and trying to widen the road in the middle of the communities would "obliterate" them, Rich said.

Also Monday, the committee meeting considered two other VDOT projects, both involving Route 7.

The agency recommended a series of modest improvements to the three-mile stretch between Countryside Boulevard and Dranesville Road to ease traffic, especially at clogged intersections such as the one at Sterling Boulevard. The improvements would include such measures as altering turn lanes and encroaching on medians.

VDOT analyzed traffic patterns in the area, in part at the behest of Staton, who lives nearby and said during his 2003 campaign that he would make alleviating congestion on that stretch of highway a priority.

VDOT estimates that construction costs would be about $1.8 million, but that amount does not cover the entire project. Committee members have asked county staffers to come up with a plan and to estimate the cost of designing the improvements, moving utility infrastructure and securing rights of way, according to Charles E. Taylor, assistant director of Loudoun's office of transportation services.

A VDOT official also provided an update on a problem-ridden plan to facilitate travel on Route 7 in Loudoun and Fairfax counties by synchronizing traffic lights.

Beginning last year, VDOT installed 76 cameras at 22 intersections from Leesburg to Tysons Corner and began using them in March, according to Richard W. Steeg, a VDOT administrator who briefed the committee.

But many of the cameras failed to accurately detect vehicles, a function that is crucial to adjusting the timing of signals.

"The technology is known to have some issues with it," Steeg said. He said that the Federal Highway Administration was investigating what went wrong and that its report was due to be completed in late January.

Traffic heading east on Route 50 backs up at Gilberts Corner at Route 15, where a roundabout is scheduled to be built.