Republican lawmakers in Northern Virginia will propose a plan next week to generate $5 billion during the next 20 years for road and transit construction without raising gasoline taxes, according to one of the leaders of the group.

By borrowing against the tax revenue that residents pay on their insurance premiums, the GOP lawmakers say, the state could raise billions to build roads, bridges, transit systems, tunnels and interstates. But the plan counts on an improving economy boosting the state's tax revenue by $500 million to $700 million over the next two years. That would allow the state to use an equal amount from the insurance tax to pay off transportation bonds, supporters say.

More than a dozen lawmakers are scheduled to unveil details of the proposed legislation at a news conference Tuesday.

"The key word is 'prioritize,' " said state Del. Timothy D. Hugo (R-Fairfax), who helped develop the proposal. "We have an excess surplus that will arrive in January. There will be a feeding frenzy of people who want to spend that money. What we are saying is prioritize it to transportation."

The lawmakers are to be joined by representatives from several Northern Virginia business groups who have lobbied for years for more transportation money. William D. Lecos, president and chief executive of the Fairfax County Chamber of Commerce, said he believes the GOP proposal has merit.

"Would it be great if every surplus dollar went to transportation? You could certainly use it," Lecos said. "This is a starting point."

In their last session, lawmakers raised sales and other taxes by $1.5 billion to pay for increased spending on schools, colleges, public safety and health care. But virtually no new money was added to the state's struggling transportation program, which was forced to slash proposals already on the books.

Now, politicians in both parties say they want to address the vexing issue of transportation funding, perhaps as early as the next legislative session, in January.

Aides to Gov. Mark R. Warner (D) say he is actively developing his own proposals. Lawmakers close to Sen. John H. Chichester (R-Stafford) say the Finance Committee chairman is preparing his own plan. And Speaker William J. Howell (R-Stafford) has appointed a committee of GOP House members and has hired an outside consultant to study the transportation problem.

"I think it's great we're all working on new ideas and different ways to approach it," Howell said. "I haven't dug into their proposals. We're looking at all sorts of options, and I'm sure this will be part of a much bigger package." But the GOP plan -- which was developed by Hugo and Del. David B. Albo and House Appropriations Chairman Vincent F. Callahan Jr., both of Fairfax -- is the first major proposal to be unveiled since the extended 2004 session ended in early May.

It would fund a spurt of transportation construction by relying on taxes that Virginia residents pay on their home, life and auto insurance premiums.

If that money was used to pay back state bonds, it could raise close to $5 billion over two decades for transportation. But that could also force the state to abandon other borrowing for prisons, schools and college buildings.

"It takes time to develop a dialogue," Hugo said. "You have to start these things early."

Initial reaction to the GOP plan was mixed.

Many of the legislature's top Republicans, including Chichester, have long opposed increased borrowing, especially when the source of money to pay the debt is uncertain. Lawmakers voted in 2000 to dedicate a portion of the insurance taxes to transportation but have failed to live up to that promise for several years.

Ellen Qualls, spokeswoman for the governor, said lawmakers should remember that they rejected Warner's proposal earlier this year to dedicate a smaller amount of insurance premiums tax to transportation.

"That said, let's see what they actually propose on Tuesday," Qualls said yesterday.

Senate Minority Leader Richard L. Saslaw (D-Fairfax) immediately rejected the GOP idea, likening it to a raid on the state budget that would take away money from teachers, health care, police officers and other state programs.

"This is the same mentality that gave us the car tax [cut] out of the general fund," Saslaw said. "When the you-know-what hit the fan, we had to start making massive cuts everywhere. These are guys who will do absolutely anything to avoid a tax, and they don't care what kind of damage they do behind."

Saslaw said a more responsible approach would be to raise the state's gasoline tax, which is 17.5 cents a gallon. Lawmakers have been wary about proposing such an increase because of the high cost of gas.

"If they want to do something for transportation, let's do it with the gas tax," said Saslaw, who owns several service stations in Northern Virginia. "I wouldn't have any problem doing that."

Fairfax County Board of Supervisors Chairman Gerald E. Connolly (D) was more charitable.

"All of us need to stay flexible," he said. "It's not as if the new revenue projected has no other claims. But I applaud and support the fact that people are beginning to step up to the dialogue."