Soaring construction costs have boosted the anticipated cost of North Carolina’s first toll roads, officials said, making it imperative for lawmakers this year to commit millions in taxpayer money over the next 40 years to cover the projects.

With the money included in the recently approved state budget and another measure detailing toll collection methods awaiting Gov. Mike Easley’s signature, North Carolina Turnpike Authority officials say the state’s first pay-as-you-drive highway is on track to open in 2010.

The General Assembly created the authority in 2002 to oversee the creation of new roadways in congested areas. Supporters said motorists would stomach the tolls in return for new byways that couldn’t be built without the revenue.

Six years later, the authority plans to complete a large portion of its first project, the Triangle Expressway in western Wake County, by 2010.

With the road, North Carolina would join 34 other states that already have toll roads, according to the International Bridge, Tunnel and Turnpike Association.

But the Triangle Expressway, which will connect existing highways in western Wake County, currently bears a $967 million pricetag, roughly twice what earlier estimates predicted, said Turnpike Authority executive director David Joyner.

That increase largely is because of the mounting costs of steel, concrete and asphalt. Road building supplies have nearly doubled over the past five years, by some groups’ estimates, as international demand has grown and energy prices have skyrocketed.

For example, the first leg of the project known as the Western Wake Parkway, a 12.6-mile stretch connecting NC 55 from Old Smithfield Road to Alston Avenue, was estimated at $261 million in 2004, according to turnpike figures. That authority now estimates the road will cost about $800 million in 2010, because of increased costs and inflation.

The tolls, which Joyner estimates will be about 13 cents per mile, won’t cover the bonds and federal loan turnpike authorities plan to secure to pay for the construction.

“With toll roads, I think there’s a misconception among a lot of people that tolls pay for the entire cost of the road, but that’s not true,” Joyner said.

So lawmakers budgeted $25 million for the road each year until the debt is paid. Joyner said that will take 40 years.

State backing for toll projects often helps authorities secure financing or better loan rates, said Neil Gray with the International Bridge, Tunnel and Turnpike Association.

“It shows they’ve got skin in the game,” Gray said.

The budget calls for millions more to be put into the authority’s other planned projects: $24 million each year for the Monroe Connector/Bypass; $15 million for the Mid-Currituck Bridge; and $35 million for the Garden Parkway in Mecklenburg County.

In sum, about $99 million in taxpayer money will go toward the toll road projects each year over the next roughly four decades.