A Northern Virginia lawmaker on Monday will renew his push to have the commonwealth buy the privately owned Dulles Greenway toll road despite warnings from Virginia's top transportation official that such a deal may not be financially viable.

A General Assembly subcommittee will take up legislation from Del. Joe May, R-Leesburg, that would allow Virginia to take over the private, 14-mile toll road west of Washington Dulles International Airport that's now run by the Macquarie Group.

But Virginia Secretary of Transportation Sean Connaughton raised questions about whether the state could afford to buy the road given how much debt its current owners have run up.

"We've been running numbers. It's a pretty big debt load that they have on the Greenway," Connaughton said at a Northern Virginia event last week. "It would be very difficult for the commonwealth to take over given that."

May remains optimistic, saying he will sit down again with the Greenway's owners Monday for another round of informal negotiations. May said he's not worried about the owners' debt that the state would have to assume, though he wouldn't say how much the debt is.

"They have a problem all right, but that's basically their problem," he said, saying the state could take over the bonds for the toll road without taking over the debt.

The state pays much lower interest rates on its bonds --about 4 percent compared with the 14 percent obtained by the Greenway owners -- and so the state could still afford to buy and run the Greenway, May said.

"What Virginia can offer and what they can afford to take is becoming apparent," May said, indicating that the state is close to coming up with a price for the toll road.

The Leesburg lawmaker said buying the Greenway could cost Virginia nearly $1 billion, but that Virginia could issue bonds to raise the money.

May wants to buy the Greenway to keep toll rates low for his constituents who use the pricey road -- if Virginia bought the Greenway, May said earlier, the state could keep tolls at the same rate they are now instead of raising them repeatedly, as the current owners have done.

The move to buy the Greenway comes even as the state's utility watchdog, the State Corporation Commission, this month approved another request from the Greenway's owners to raise toll rates. A one-way trip the length of the Greenway for cars during peak periods now costs 10 cents more, or a total of $5.90.