An economic advisor to Gov. Bob McDonnell has resigned to protest the Republican leader's backing of a statewide tax hike to help fix Virginia's crumbling, crowded roads.

In a letter to McDonnell dated Friday and obtained by The Washington Examiner, Richard Rahn said he was stepping down from his post on the Joint Advisory Board of Economists because "I strongly disagree with the new tax/transportation bill that you supported."

"A number of other Republican governors are supporting major rate cuts in their state income taxes, and in several cases proposing to totally eliminate the state income tax," Rahn wrote. "Virginia should be doing the same."

Rahn is chairman of the Institute for Global Economic Growth and a former vice president of the U.S. Chamber of Commerce. He was appointed by McDonnell to the 15-member advisory board, which meets once a year to provide an economic forecast for McDonnell and the General Assembly.

McDonnell's administration acknowledged they received Rahn's resignation.

"He was a valuable member of the Joint Advisory Board of Economists," said state Finance Secretary Ric Brown, who chairs the advisory board. "I respect Dr. Rahn immensely. I think he stated his principles in the letter and for that he has his view."

Rahn also criticized McDonnell for not seeking the board's opinion before getting behind the transportation package, which will raise $880 million a year for roads through a series of tax increases.

"I was not asked for my advice before you and the legislature embarked on passing the largest increase in taxes in the history of Virginia," Rahn said. "This action will do damage to the people of the Commonwealth of Virginia."

Brown, who has worked in state finance and budgeting for four decades, said it would have been an extraordinary action to reach out to the board on legislative issues.

"It's not their role," Brown said. "It would have been inappropriate given what that board was charged with and practically speaking, over my course of employment, something that would have been way out of the normal."