Debating the Economic Toll

A free-flowing road -- even an expensive one -- helps to prevent late deliveries, cancellation of meetings and missing of flights and could result in a net positive for local business, Mudge said.

There is also no consensus on how high tolls would have to get before large numbers of drivers abandoned the Greenway. Some analysts said that even the approved increases probably will not trigger such a reaction in Loudoun, which has the second-highest median income of any county in the nation.

"When you have pretty high demand, you're going to have pretty high tolls," said Ronald F. Kirby, director of transportation planning at the Metropolitan Washington Council of Governments. "It's a well-to-do region. . . . People driving downtown might be paying 13, 14 bucks a day to park. . . . Even though those toll rates sound high . . . you wouldn't expect it to frighten people off."

Toll hikes on the Greenway have not resulted in significant spurts in usage of other roads, said Art Smith, senior coordinator for planning and development with the county's Office of Transportation Services.

"Its volumes are growing but not spurting," Smith said of Route 7. He said he does not think that a lot of people have been switching to Route 7 because of the tolls, "but there could be as the tolls continue to go up."

Smith also cited plans to replace stoplights with interchanges on Route 7 between the Leesburg Bypass and Route 28 over the next few years. He said the improved traffic flow would result in an incentive for drivers to choose the secondary road over the Greenway.

To further complicate matters, even if the high tolls scared commuters onto secondary roads en masse, the gridlock would probably push them back onto the Greenway, Mudge said.

"If the congestion gets so bad on these roads, they'll say, 'Oh, it is worth it,' " he said. "It's a feedback effect."

There may be only one certainty about getting around in Loudoun in the years to come: Drivers will pay -- either with their wallet or with their time.