Virginia transportation officials are asking private businesses for help in building a 50-mile highway that would stretch from Interstate 95 in Stafford County to Route 7 just east of Leesburg, reviving a controversial project that has flipped on and off state plans in recent years.

The road, known as the Western Transportation Corridor, is designed to bypass -- and ultimately ease -- the congestion of the Capital Beltway and serve rapidly growing populations and job centers on the outer tier of Northern Virginia.

The search for private proposals resumes a process that ended in spring 2003, when the highway was one of several projects clipped from the state's six-year plan because of severe budget problems.

Those money constraints have led the state to turn to private firms to fill the void through its public-private transportation act. This year, officials approved a public-private venture to widen the Capital Beltway, and they are considering proposals to upgrade parts of Interstates 95 and 395, as well as other roads.

But while private investment has worked elsewhere, where the companies could make a profit, officials said they are less optimistic about finding a builder for the western bypass because of environmental constraints and its high price tag. The road was estimated to cost $1.3 billion in the late 1990s, but state officials said it would run at least double that because of rampant residential and commercial development along its path and the rising cost of real estate.

"We're really trying to answer a simple question: Can this facility be funded through tolls," said Deputy Transportation Secretary Pierce Homer, who said firms have until Jan. 14 to submit proposals. "If the answer is no, end of story. If the answer is yes, things could potentially happen."

Business leaders said they were happy to see some action on the highway. "I applaud the fact that they're trying something," said Leo J. Schefer, president of the Washington Airports Task Force, a lobbying group that tries to bring business to the airports. "I hope they get somebody to bite."

Public-private deals have drawn questions from environmentalists and smart-growth groups who fear that firms will use them to spawn development rather than to solve traffic problems. Those same organizations oppose the western bypass, saying it would catalyze suburban sprawl in areas that are turning from open space and farmland into cul-de-sacs and shopping centers.

"The only people who think this is a good idea are speculative landowners who want it to fuel their land-use dreams, and that's exactly the thing that concerns us," said Christopher J. Miller, executive director of the Piedmont Environmental Council. "We pretty much view it as a real threat to the vision of the piedmont area as something more than sprawl."

Miller also said he was concerned that the state solicited offers for a road that elected leaders have not demanded. "This is not something identified as a public priority," he said. "I find it very troubling that the Department of Transportation would forward this as a vehicle for the development community."

Plans for the highway gained approval from leaders in the four counties it would traverse -- Stafford, Fauquier, Prince William and Loudoun -- in 1997, but the political and literal landscape has shifted considerably since then.

In 1998, state Sen. John H. Chichester Jr. (R-Stafford) crafted legislation that essentially killed the project, although it remained in state plans. Local support is also less certain, as the boards of supervisors in all four counties have almost completely turned over and tens of thousands of new homes have replaced the hills and farmland along the road's path.

Supervisors in Loudoun who were elected on a pro-development platform are reconsidering the highway as part of an overall review of county plans. But there also is concern from some there that it would dump thousands of cars onto crowded Route 7, similar to concerns officials in Stafford have about traffic on I-95.