Private financing of public roads in Virginia is more concept than fact, says an analysis by an environmental group.

Little of the money spent to build roads under the state's Public-Private Transportation Act actually comes from private sources, according to the Southern Environmental Law Center, based in Charlottesville.

Still, the public-private approach to road building is gaining steam in Virginia. It's a key to widening Interstate 81.

General Assembly members often say the PPTA is the only way to build roads without increasing taxes.

Gov. Mark Warner proposed a $140 million revolving loan fund last week to jump-start PPTA proposals, using money from this year's state surplus.

That's the approach that the environmental group criticized.

"The law is failing to live up to its promise of attracting private money to fund increasingly expensive projects," the SELC said in a news release.

Virginia has signed six construction contracts under the PPTA process, and two maintenance contracts. Their total value is $1.135 billion. VDOT says nearly two-thirds of that, $721 million, comes from state and federal tax dollars, the traditional sources of road construction.

U.S. 58 in Patrick County and the Coalfields Expressway in Southwest Virginia are two of the PPTA projects.

Five other transportation projects are proposed under PPTA, including I-81, three in Northern Virginia and one in Hampton Roads.

Part of the argument posed by the environmental group hinges on what constitutes private funding.

Money earned from tolls is private funding, in the eyes of the Virginia Department of Transportation.

The SELC argued that there's little difference between tax dollars and tolls.

"Projects proposed under the Public-Private Transportation Act rely almost exclusively on tolls and/or taxpayer dollars," the SELC said.

That's the way it was meant to be, VDOT says.

"If the assumption was, when PPTA came out, that all private money would come and build these things, then what they're saying is correct," said Mal Kerley, VDOT's chief engineer.

But highway projects will always require some public tax dollars, Kerley said. Anytime private money is used to build roads under PPTA, it will be raised by selling bonds, and those are paid for with tolls, he said.

"You're always going to have the tolls aspect on that," Kerley said.

Private companies that invest in roads are entitled to earn a profit, and the only private revenue source is tolls.

There have been suggestions that Virginia generate revenue by allowing service centers on its highways, similar to the food and gas businesses on the tolled turnpikes in New Jersey and West Virginia.

Under existing law, VDOT cannot lease land on its right of way to stores, restaurants or gas stations. "We can't condemn land and give to somebody else who can make money on it. That's not what we do," Kerley said.

Kerley directs VDOT's PPTA operations. He was a member of the advisory panel that recommended a year ago that the state agency negotiate with the Star Solutions builders consortium to widen I-81 under a unique financing plan that includes earmarked federal funds, tolls on trucks, and a federal loan.

Contract negotiations are still under way between VDOT and Star Solutions, and VDOT is conducting an environmental review that's expected to take most of this year to complete.

Each of the six PPTA construction projects in Virginia has slight differences in the financing packages.

Yet, the one completed project, the Pocahontas Parkway near Richmond, is coming up short on toll revenue. Kerley said that if the financing outlook doesn't improve, the private association that sold the parkway's bonds will have to decide how to refinance them.

Lowering tolls to attract more motorists, or raising tolls to bring in more money, would be two traditional options. Kerley said Virginia has no legal obligation to bail out the road with tax dollars.

Those types of conflicts have taken the PPTA process in unexpected directions, the SELC said.

"The PPTA has evolved into a process of large construction consortiums proposing design/build projects that primarily use taxpayer-subsidized revenue bonds backed by tolls or local taxes, supplemented with whatever traditional government transportation revenues are available," the SELC report said. It was written by James Regimbal, a fiscal analyst who has done budget work for the state of Virginia and other clients.

One step in the evolution has been a new interest in how bonds are backed.

VDOT Commissioner Philip Shucet says he wants the consortiums to invest in the bonds that would finance their projects.

If a consortium approached VDOT with a plan that included buying 25 percent of the bonds on a project, Kerley said, that would indicate the project would pay a good profit.

"We encourage the private sector to do that," Kerley said.