Virginia Republicans are calling on one of their own, Gov. Bob McDonnell, to lead the fight for badly needed transportation funding over the next year -- his last year at the helm.

"He came into office saying that he was going to fix transportation. To date, it's not fixed," said Sen. John Watkins, R-Midlothian. "It's a huge opportunity for him to leave a legacy."

Virginia governors have come and gone every four years without seriously addressing the need to increase spending on road construction, and the problem is about to reach a tipping point. By 2017, there will be no more state money for new projects, only basic maintenance.

McDonnell did pass a $4 billion highway and rail plan, but the state borrowed the money needed to fund those projects. The one funding source dedicated to transportation -- a 17.5-cent tax on a gallon of gasoline -- is no longer providing enough money to cover repair costs and priority projects.

McDonnell said last week that he was "evaluating" a proposal to replace the gasoline tax with a sales tax that could be increased along with inflation. And while the governor said Tuesday that he doesn't consider that kind of change a tax increase, he insisted that he's not advocating such a change.

"I was simply saying there's a problem in our current way of funding transportation," McDonnell said on WTOP's "Ask the Governor" program.

Some Republicans believe that if McDonnell stood behind a plan to raise the gas tax by indexing it to inflation, lawmakers in his party would follow suit.

"It's not going to pass unless the governor decides to jump on board with it," said Del. Dave Albo, R-Springfield. "But he has been very vocal and forward about the problem. Knowing Bob, I expect he'll do something about it."

McDonnell said he will unveil a package of transportation reforms in the coming weeks that will likely include a proposal to shift money from the state's general fund budget -- the portion used to fund schools and other state programs -- to use on roads, a move Democrats worry would undermine other priorities.

Lawmakers, too, are proposing solutions of their own. Watkins filed a bill for next year's General Assembly session that would impose a tax on gasoline sold wholesale. The bill is structured so that most of that tax burden would fall on out-of-state drivers. Watkins would cut Virginia's income tax to offset the added cost to residents.

Watkins is waiting to see McDonnell's latest proposal, though he said previous offerings -- including new tolls and greater borrowing -- haven't been enough to meet the state's multibillion-dollar needs.

"Most of what has been offered has been very short-term and very specific. That's a stop-gap measure," Watkins said. "I do not know what [McDonnell is] going to propose, but I'm anxious to see what it is."