The board that oversees transportation decisions in Virginia has delayed a vote that some say would have further advanced a proposed parkway connecting the counties of Prince William and Loudoun.

The Commonwealth Transportation Board was scheduled Wednesday to accept a study examining the North-South Corridor, which includes the so-called Tri-County Parkway, a proposed 10-mile thoroughfare that would connect I-66 in Prince William to Route 50 in Loudoun. The corridor also includes the area west of Route 234 to I-95.

But the CTB has moved off the vote. Transportation Secretary Sean Connaughton said in an interview that some had overemphasized the importance of the CTB vote, which would have accepted a study that includes localities’ long-range plans for transportation, including the proposed parkway. Rep. Frank Wolf (R-Va.) had sent a letter just before the CTB meeting to Gov. Robert F. McDonnell (R) saying that the state needed to be more transparent and slow down its efforts.

Connaughton said he hopes that recent opposition to the project would subside once residents and officials realize the parkway’s benefits.

“The [parkway] will be a major benefit to the residents of western Prince William,” Connaughton said. “Our studies show that Route 15, 234 and 29 ... will become overwhelmed by traffic in the next 20 years. People are concerned about traffic now. They will be screaming about the tens of thousands of cars that will be stuck on these two-lane roads.”

The decision to delay the corridor study comes as controversy around the issue has escalated in recent weeks. Wolf said in his letter that he had “serious reservations” about the road. He outlined several potential problems, including that it would open up Prince William’s protected rural area — called the Rural Crescent — to development, and that it would be paid for in part with tolls.

He also said that Dulles International Airport officials have told him that claims made by state transportation officials about the road’s ability to increase cargo movement to the airport are not true. “Believe me, every time there’s a problem with the airport, they come here,” Wolf said in an interview.

John E. Potter, president of the Metropolitan Washington Airports Authority, signed a letter this week proclaiming the airport’s support of the project. Further, MWAA officials said in a statement that the proposed road would be a boon for both counties.

“While enhanced access to Dulles International Airport would have a positive impact on the airport, the much bigger benefit from the proposed project is the improved mobility and economic development the project will provide the region,” MWAA said in a statement provided by spokesman Christopher Paolino. “Anything that increases mobility and economic development in the region is good for the airport. This is a road to jobs for Prince Williams and Loudoun counties.”

Dan Scandling, Wolf’s chief of staff, said that the airport’s argument has little to do with moving cargo.

“The whole issue is back to transparency. What is this project for?” he asked. “You kept hearing this talk of cargo ... apparently that is not the case. It is being sold for one thing when it may be something else, and that is not fair to anyone in the process.”

Wolf said the state should develop a “cost-benefit analysis” of the road and other potential projects to improve transportation congestion before moving forward.

“More public hearings must be held and more citizen input must be received before any final decision is made,” Wolf wrote to McDonnell. “I have seen the reaction of Prince William residents. What will Loudoun’s residents say as planning continues?”

State transportation officials have scheduled a meeting for residents to weigh in at the Hylton Performing Arts Center on June 3 from 6 to 9 p.m.

The parkway’s supporters, particularly the business community in both Prince William and Loudoun, say the road would create jobs and drive area economic development, ease congestion and provide a key connection between two rapidly growing counties.

Wolf is the latest Republican to voice opposition to the parkway. Six state Republican legislators announced last month that they oppose the road for many of the same reasons Wolf does.

The parkway’s detractors have become increasingly worried about the road’s renewed prospects given new dollars for transportation made possible through a sweeping transportation bill passed this year.