Up until now, Gov. Nathan Deal

has issued little more than an attaboy to the lawmakers crafting a complicated plan to raise new transportation revenue. The House's proposal to raise $1 billion was an important first step, he said, but he wouldn't go so far as to endorse it.

That changed Wednesday when discussed a few more guideposts that he wants legislators to keep in mind as they vet House Bill 170.

The switch from a range of local and state sales taxes on gas to a straight 29.2 cents-per-gallon excise tax should be locked in, he said, as a guaranteed revenue stream for transportation projects. Local officials have complained that the move would transfer to the state more than $500 million that they have used for schools, transportation and more, leaving them to fill in the gap.

And Deal said he favored the plan to add $200-$300 annual user fees on drivers of electric cars and other alternative vehicles. He said it's "appropriate" that those drivers, who don't pay fuel taxes but use the roads, start paying a share.

But he drew a line when it came to the plan's proposal for a hefty bond package for transportation projects, which would include $100 million in funding for transit. He said his concern is that it's a one-time fix, and relying on bonds in future years could jeopardize the state's AAA rating.

"We would be mistaken if we think we can solve the long-term transportation problems of this state by simply using a one-year bond package," said Deal. "We would also be equally wrong to think that, every year, we could have a large bond package to cover those costs. I believe it is more prudent to have a transportation reform package that builds into it a sustainable amount of revenue on an annual basis that does not have to be tampered with, or have large infusions of money from a bond package, to make up for the deficiencies that exist."

He would not say how he would get there, leaving that task up to lawmakers. And he was more circumspect about another proposal that has surfaced by state Rep. Earl Ehrhart that could halt a tax break and divert that revenue to transportation projects.

House Bill 175 would end Delta’s lucrative state tax credit on fuel and Ehrhart said some of the more than $20 million the firm saves each year on fuel could help fund transportation projects. Deal declined to comment on the bill, saying only that "everything is on the table" when it comes to raising new transportation revenue.