RICHMOND -- Two major Roanoke Valley interstate highway projects and a New River Valley bridge replacement could be pushed out of the state's six-year highway construction plan as transportation officials continue to struggle with mounting needs and diminishing funds.

Money for planned improvements to a congested Interstate 81 exit in Botetourt County and the I-581 interchange at Elm Avenue in Roanoke would be cut under proposed revisions to the six-year plan unveiled Wednesday before the Commonwealth Transportation Board.

The revised plan also would reduce funding for replacing a bridge over the New River on I-81 in Pulaski County, according to a list released by the Virginia Department of Transportation.

The revised plan also cuts more than $32 million from more than two dozen secondary and urban road projects in VDOT's Salem District in order to direct dollars toward primary highway projects.

The cuts are part of a broader plan to address a projected revenue shortfall of $851.5 million over the next six years. State transportation agencies also will reduce administrative, operational and maintenance costs to balance the budget, officials said.

"What we're trying to simply do is to maintain some semblance of responsibility toward our core responsibilities," said Secretary of Transportation Pierce Homer.

Virginia's six-year highway construction program has been reduced from $8.6 billion to $5.5 billion over the past two years because of the economic recession and a decline in federal and state transportation revenue.

The latest cuts underscore the challenge that governor-elect Bob McDonnell will face when he takes office in January. McDonnell has vowed not to raise taxes to tackle the state's road and transit needs, instead relying on a mix of funding ideas that include borrowing, privatizing state liquor stores and imposing tolls on certain interstates.

The total highway funding in the plan released Wednesday differs little from the amount contained in a plan the transportation board approved in June. But officials made significant adjustments to projects and construction timelines based on policy and revenue changes.

"We have worked diligently to keep projects on track that support our main priority areas, but this program represents the continued reduction of our ability to build and maintain secondary and urban highways," Homer said.

The draft plan would shift nearly $11 million from the Elm Avenue project, $12.3 million from the I-81 Exit 150 in Daleville and $15.7 million from the I-81 bridge replacement project in Pulaski County. All of those projects have some preliminary funding in the plan.

"The only reason I'm not devastated is because I'm not surprised," said Dana Martin, the Salem District representative on the transportation board. "It's symptomatic of the problems with funding. ... We're going to have costs far beyond the construction in terms of congestion and lost economic opportunity in the future."

The transportation board will hold a public hearing on the draft plan Dec. 1 in Richmond and vote on the revisions at a separate meeting later in the month.