Drivers on I-66 would be subject to new tolls under Gov. Terry McAuliffe’s plan. GOP candidates for the House of Delegates are using that fact against their opponents. (Marvin Joseph/Washington Post)

Two Northern Virginia Republicans running for the House of Delegates will launch a $336,000 TV ad campaign on Wednesday that links their Democratic rivals to Gov. Terry McAuliffe’s plan to turn Interstate 66 inside the Beltway into a toll road for some commuters.

The network television ads — a rarity for House races in the expensive Northern Virginia TV market — are part of an unusually coordinated strategy by Republican House candidates in that traffic-choked region of the state.

With yard signs, mailings, telephone town hall meetings and a $45,000 digital plan that includes Facebook and targeted video ads, Republicans have hammered home a simple slogan with visceral appeal for weary commuters: “Stop $17 tolls on I-66.”

The GOP’s intense focus on the issue is all the more notable because Democrats across the region have said they, too, oppose the governor’s plan.

But Republicans say Democrats cannot be trusted to push back against their fellow Democrat in the governor’s mansion. They are using the issue across Northern Virginia, but most intensely in the three most competitive House races.

One is a rematch between Del. Kathleen Murphy (D-Fairfax) and Craig Parisot (R). Murphy narrowly beat Parisot in a special election this year to fill the seat vacated when Barbara Comstock (R) moved to Congress. The others are for seats being vacated by Dels. Thomas Davis Rust (R-Fairfax ) and David I. Ramadan (R-Loudoun). Republican Danny Vargas is competing with Jennifer Boysko to replace Rust. Republican Chuong Nguyen faces John Bell for Ramadan’s seat.

Parisot and Vargas are launching the TV ads.

“First Kathleen Murphy supported raising our taxes,” begins Parisot’s ad. “Now there’s governor McAuliffe’s plan for $17 tolls on I-66. Murphy touts McAuliffe’s support and can’t be trusted to stop the tolls. And Murphy is funded by insiders pushing McAuliffe’s agenda. . . . Reject $17 tolls, reject Kathleen Murphy.”

Vargas’s ad against Boysko is nearly identical but for the Democrat’s name.

Some Democrats said they have been surprised by the campaign because they have spoken out against the I-66 plan at public meetings and in their own campaign literature.

“It seems to be a coordinated effort,” Murphy said. “I’ve seen it everywhere, and I don’t really understand. It’s just patently dishonest because all of us have come out against this plan. . . . They figure if they say it loud enough and put it on TV, people will believe them.”

Murphy has received support from the Democratic Party of Virginia, which McAuliffe’s political action committee largely bankrolls. But she said that will not shape her stance on I-66.

“Kathleen Murphy opposes tolls on I-66,” reads a mailer she issued in response to Parisot’s campaign. “People already pay too much in tolls.”

Republicans do not dispute that their Democratic rivals are on the record against the project. But they contend that the Democrats would have trouble maintaining that stance if they win office thanks, in part, to McAuliffe’s support.

“Who can you trust to go to Richmond?” Vargas said in an interview, describing Boysko as being “tied at the hip to the governor.”

McAuliffe’s tolling plan, which state transportation officials plan to implement in 2017, is meant to deal with single drivers who evade carpool regulations on I-66 that require vehicles traveling on the road inside Interstate 495 during rush hours to have at least two people.

Virginia Transportation Secretary Aubrey L. Layne Jr. said opponents of the plan are falsely claiming that tolls would go up for everyone who uses I-66. The tolls would not be imposed on carpoolers, only on single drivers who choose to use the toll lane.

“If you’re carpooling now, obeying HOV [high occupancy vehicle] laws, that remains the same,” he said. “That’s just an inaccurate statement that there will be additional tolling. . . . I know it’s election season and all that, but these are difficult decisions and we’re open for discussion with real issues, but we ought to deal with the facts.”

McAuliffe’s I-66 plan sparked criticism from the start from Northern Virginia lawmakers, Democrats included. But Republicans began playing up the issue over the past three weeks in the run-up to legislative elections.

Virginia House Speaker William J. Howell (R-Stafford) and other state Republican leaders called a news conference at a Fairfax County park overlooking I-66 to denounce it as “outrageously expensive” for commuters. They objected to adding tolls without adding lane capacity.

Republicans said the issue has been resonating with voters encountered face-to-face and through polling.

“All of our pollsters told us this is the best issue they’ve seen in Virginia since the car tax,” said Matthew Moran, a spokesman for Howell. Republican Jim Gilmore won the governor’s office in 1997 on a promise to eliminate that unpopular tax.