Interstate 66 traffic looking west in Vienna, Va. The trees on the right cover the sound wall that protects homes directly behind it. Virginia is set to begin a $2.3-billion project to widen I-66 outside of the Capital Beltway. (John McDonnell/The Washington Post)

With only a few months before the kickoff of major construction to widen Interstate 66 outside the Capital Beltway, a push to change the design of the project’s multiuse trail could jeopardize the entire $2.3 billion project, Virginia’s transportation chief said.

Bike advocates, trail aficionados and some state lawmakers who are worried that portions of the planned pedestrian and bike trail are too close to traffic lanes have called on the state Department of Transportation to move the path from the highway side to the residential side of a sound wall that is part of the project.

But the change would violate a requirement in the project’s contract to locate the trail on the highway side in areas adjacent to homes, a deal state officials say was reached after years of negotiations and compromises to reduce the impact on homeowners. Already, some residents of the area are braced to see their back yards shrink to make way for the wider road. Changing the trail location would require additional right of way, officials said.

“This will jeopardize the entire deal if we go back to the homeowners now and tell them we are going to take more of their property,” Transportation Secretary Aubrey Layne said. It also would be costly to the state, Layne said, and delay the project, which is set to break ground next year for a scheduled completion in 2022.

“That’s just not fair — and it’s not necessary, ” Layne said.

The trail is part of the planned expansion of I-66 outside the Capital Beltway, a project that will add high-occupancy toll lanes to the corridor. It will expand travel lanes to include three general-purpose lanes in each direction; new and expanded transit service, including additional park-and-ride lots; and median space reserved for future rail service.

Part of the Interstate 66 sound wall runs behind Michael McDonald’s house in Vienna. An avid cyclist, McDonald said he favors building bike infrastructure and considers the trail along the highway a safe alternative given the physical constraints just outside the road. (John McDonnell/The Washington Post)

The expansion spans 22.5 miles from the Capital Beltway in Fairfax County to University Boulevard in Gainesville in Prince William County.

State transportation officials say the expansion will help reduce congestion in the I-66 corridor, which experiences eight to 10 hours of gridlock daily, including weekends, and carries roughly 200,000 vehicles on an average day.

Because of space constraints, about five of the 16.5 miles of proposed trail in Fairfax are planned to be placed alongside the highway’s traveling lanes, with a jersey barrier and fence separating it from traffic.

An additional six miles of trail along the corridor in Prince William is being coordinated by the county.

Criticism of the plan continues to grow; 19 state lawmakers recently wrote to Layne saying the design is “insufficient” and arguing that the trail users who will be sandwiched between a sound wall and traffic will be exposed “to concentrated quantities of car exhaust, noise pollution and road debris.”

The letter was backed by more than a dozen groups including state, regional and local bicycling associations. Most of the lawmakers who signed it are from Northern Virginia, but none represent the Fairfax neighborhoods most affected by the project. Some represent districts as far away as Virginia Beach and Roanoke.

In Layne’s response on Tuesday to lawmakers, he offered no suggestion that the state intends to shift the plan significantly at the expense of homeowners. In an interview, he said the state will work with the advocates and the project’s private partner to reduce the length of trail that can’t be accommodated outside the highway. He said the trail will be safe, aesthetically pleasing and elevated, where possible, to enhance the user experience.

“It would be not wise to start opening [the contract] just for this one constituency,” Layne said. “I do take very seriously the deal and the promise to the homeowners that we would not impact their homes any more than necessary.”

The state is looking to find locations within those five miles — spread throughout the corridor — of trail where the facility could be moved to the other side of the wall. Any modified design would be released for public review this fall.

Talk of revisiting the trail design has stunned many residents of the area, who say their lives will be negatively impacted by any more changes — especially after such a long-fought process to get to the current plan.

Over the past two years, dozens of meetings and discussions were held to reach compromises to minimize the impact on the properties, said Fairfax County Supervisor Linda Q. Smyth (D-Providence), who represents much of the area in question.

Preliminary design plans indicate that the project would directly affect about 200 private and ­commercial properties, mostly through partial acquisitions. Eleven homes will be taken to make way for the widening of the road, a number that was reduced from 35 during negotiations, officials say.

“This has been a wrenching experience for the neighborhoods and the people who are closest to it,” Smyth said.

A rendering of the proposed bike trail that would parallel Interstate 66 outside of the Capital Beltway. (Express Mobility Partners)

Major construction is slated to start next spring, but some early construction activities — such as utility relocation, clearing and grubbing, and erosion and sediment-control — may start by the end of the year. Residents are looking at five years of construction.

Some homes are only 10 yards from the sound wall. Parents at a local elementary school have protested having a trail adjacent to the school fields where children play. Residents also are concerned about lighting, privacy and strangers in their back yards — and losing more green space.

“We have an oasis of trees, creek and wildlife,” said Michael McDonald, a resident of a small Vienna townhouse community off Blake Lane. With the project, the neighborhood will lose some yellow poplars and, potentially, the salamanders living under the rocks near the creek, songbirds, fox and deer.

McDonald, 46, and his wife, Mirtha, have raised two children in their Vienna home. They can hear the highway noise in the background but also enjoy the canopy of trees blocking the view of the highway wall about 30 yards away.

An avid cyclist, McDonald said he favors building bike infrastructure and considers the trail along the highway a safe alternative given the physical constraints just outside the road. Even in areas near the Vienna Metro station, about a mile from McDonald’s home, the trail will go around the station rather than immediately along the highway because of limited right of way.

A rendering of the project to widen Interstate 66 outside of the Capital Beltway. It will include two new express lanes in each direction and a median for future transit. (Virginia Department of Transportation)

Charles Keener, a neighbor who moved to the area in 2009 unaware of the road-widening plans, said the last thing residents want is a bike path plowing through what little green space they have left.

“We are not against the bike path, but they have to find a way that works for the bikers but also the residents,” Keener said.

Trail advocates say they plan to continue pushing VDOT to build the trail on the neighborhood side of the wall.

“The contract, as it currently stands, puts biking and walking at the absolute bottom of the barrel,” said Katie Harris, trail coalition coordinator for the Washington Area Bicyclist Association.

“Having a trail inside the sound wall will be a loud, polluted experience. Having the trail outside of the sound wall, accessible by neighbors, will be an asset to the communities along the project corridor,” she said. “It will be an amenity that will enable residents to connect by biking or walking to the places they need to go.”

Harris said the trail advocates are sympathetic to the homeowners near the project and the impact of the road widening on private property. They say the width of the project can remain the same, regardless of whether the trail is on the highway or neighborhood side of the sound wall.

State and county officials, however, say the trail is planned on top of the utility easement, which has to be alongside the highway lanes for access. If the trail were to be relocated to the neighborhood side, it would require taking another 10 feet of right of way — at a minimum.

This will add to the pain of neighbors, Smyth said.

Because the Metro tracks are in the middle of the highway, everything that is being added in terms of the roadway has to go on the sides and into what is primarily residential neighborhoods. The noise wall, and the highway, will get closer to residences.

“These are people’s back yards. There is a privacy issue,” Smyth said. “People would be very uneasy about a trail that is right there at the edge of their back yards. The neighbors’ concerns are real, and they have been part of the process all the way along as well.”

This isn’t the first time I-66 has been widened, Smyth noted. Area residents have seen pieces of their property nibbled away over the years.

“So this noise wall is getting closer to the houses,” she said. “People remember these things.”