Page Snyder painted a sign in a field on her farm along Pageland Lane, which would be impacted by the proposed Bi-County Parkway. (Katherine Frey/The Washington Post)

On a two-lane country road in western Prince William County, the printed sign offers drivers a grim prediction: “Your commute is going to get worse.”

Whether that’s true — and for whom — is at the heart of a contentious debate over the proposed Bi-County Parkway.

The 10-mile thoroughfare, which would travel through farmland and near Civil War ground to connect Interstate 66 in Prince William County and Route 50 in Loudoun County, is seen by state transportation officials as a key piece of Virginia’s future transportation network. They say the north-south route is needed to relieve congestion on already busy roads in one of the country’s fastest-growing corridors.

But the proposed four-lane parkway has prompted an outcry from those who live near its path, particularly on Pageland Lane in Gainesville, where residents have posted the signs as part of their campaign against the road. They say the estimated $440 million project would cut off their neighborhood from the surrounding area, devalue their farmland and place a roaring thoroughfare in Prince William’s protected Rural Crescent.

The fight, for them, is about saving family plots where personal sentiment and American history mingle.

Such large-scale transportation projects typically invite criticism, especially from those directly affected. But opposition to the Bi-County Parkway is unusually broad, rallying a wide coalition of opponents. Notably, Republican legislators have taken on their own party’s administration and its allies over the road, prompting delays and drumming up visibility for the project’s detractors.

The grass-roots campaign is led by three residents who live on Pageland: Mary Ann Ghadban, Philomena Hefter and Page Snyder. The trio has organized traditional protests; peppered local, state and federal officials with letters; and posted Facebook updates on their progress.

They often meet at Ghadban’s dining room table, where answers to open-records requests about the parkway pile up. Those requests have been necessary, they say, because the Virginia Department of Transportation has not been open about its plans for the road.

“This was going to be a signed, sealed, delivered deal before the public got involved,” Ghadban said of VDOT officials’ recent efforts.

The project’s supporters, particularly the business community in Prince William and Loudoun, say the grass-roots detractors do not have the state’s long-term needs in mind. Some say the opposition was sparked by the same groups that always oppose growth in the region. The road, they say, was approved by both localities after a vigorous debate in 2005 that came after years of discussion.

“The bigger question is, does the region as a whole need this?” asked Bob Chase, head of the pro-business Northern Virginia Transportation Alliance and a prominent parkway supporter. “Doing nothing means it gets worse everywhere.”

Del. Timothy D. Hugo (R), who represents the Pageland area and parts of Fairfax County, held a news conference at the Manassas battlefield in April. Along with five other Republican state legislators, he denounced the road and called the fight against it “the third battle of Manassas.”

Hugo said that while he voted against this year’s landmark transportation bill, which makes funding for the parkway and other projects possible, he is not against transportation spending. He also said his opposition is nonpartisan. Gov. Robert F. McDonnell (R) and Transportation Secretary Sean Connaughton, a Republican from Prince William, are friends and allies on a number of issues, he said.

One of Hugo’s chief concerns about the parkway is the deal that the National Park Service has struck with VDOT. Because the road would encroach on federal land, Ed W. Clark, the superintendent of the battlefield park, must sign off on it. In exchange for the park service’s support, Clark has said that Route 234, a popular artery through the battlefield, must be closed if the Bi-County Parkway is constructed. Clark says Civil War grounds are no place for blaring horns and traffic jams, and closing Route 234 has long been a priority.

Thousands, however, use that road every day. Closing it would make “a bad project into an egregious project” and funnel more cars onto already congested I-66, Hugo said.

Connaughton declined requests for an interview.

Fran Fisher, a member of the Commonwealth Transportation Board, which oversees state transportation matters, said that “most of the people who are complaining” live near the proposed road and were part of the debates in 2005 and earlier. Still, she said, VDOT has not always been clear about plans for the road and why it is necessary. Those issues, she said, have been “corrected.”

She and others said the parkway is needed and that residents across Northern Virginia would be thankful in 20 years, when congestion is expected to be even worse than it is today.

And some business leaders say making it easier to travel between Prince William and Loudoun is key to the economic success of the two growing counties. Rob Clapper, president of the Prince William Chamber of Commerce, said residents should ask themselves: “What is the economic opportunity for the future?”

For now, though, hundreds have shown up at public meetings to express their displeasure. More than 500 people came to the Hylton Performing Arts Center on a Monday night in June to hear VDOT give a presentation and answer questions.

Observers say the anti-parkway campaign has caught on because it taps into issues that many in this more conservative corner of Northern Virginia have latched onto. The idea that the state has not played by the rules and is trampling on private property rights has enraged many.

But one of the biggest reasons the road has seen heightened scrutiny is congestion itself, observers say. In an area where nearly two-thirds of residents leave the county to work, outrage over long commutes and the slow pace of solutions is commonplace. Many who commute to and from the District don’t understand how the north-south route will help them.

Debate over traffic in the area has gone on almost as long as the ceaseless battles over Gainesville’s coveted Northern Virginia countryside. Snyder’s mother, legendary activist Annie Snyder, who died in 2002, was involved in many of those fights. She organized and defeated plans from Marriott, the Walt Disney Co. and others dating back to the 1950s.

Snyder, Ghadban and Hefter — now with a legion of supporters and Facebook fans behind them — said they would like the road to be killed. The Piedmont Environmental Council calls it “the most important land-use decision that will be made in Virginia in the next five years.”

But supporters of the road say that, for once, Virginia should get ahead of its commuting and traffic problems.

It’s unclear whether a future administration would be committed to the project, and VDOT is quickly moving forward. State officials hope that a key legal agreement over the parkway between four agencies — VDOT, the Virginia Department of Historic Resources, the Federal Highway Administration and the National Park Service — is approved by the fall.

Snyder said her group plans to keep the pressure on. Dozens spoke Tuesday at the Prince William Board of County Supervisors chambers when Clark, the battlefield superintendent, appeared before the board to answer questions about the road.

Snyder said she and others have also met with Loudoun residents looking for tips on how they can join the fight against the parkway. “It’s taken on a life of its own,” she said.