RICHMOND, FEB. 8 -- Private developers said today they have reached agreement with both homeowners and state officials on their proposal to build a 17-mile extension of the Dulles Toll Road from the airport to Leesburg, which if built would be one of the few privately owned, for-profit highways in the country.

"We think we are there," John D. Miller, president of New York-based Municipal Development Corp., told the Northern Virginia delegation to the General Assembly, of negotiations that started about a year ago.

Ray D. Pethtel, Virginia's commissioner of transportation, said in a telephone interview after the meeting that the Baliles administration is supporting legislation that would enable the private construction of the road to go forward.

"We are breaking new ground here," Pethtel said. While the transportation department initially had a number of concerns, those have been addressed in reworkings of the proposed legislation.

If the General Assembly enacts the bill, the developers still would have to satisfy a number of requirements, including local concurrence and state approvals of the specific design of the project, but passage of the legislation would be the key policy decision, Pethtel added.

The 20 landowners in the path of the proposed extension have all agreed to give the private developers the necessary rights of way for the toll road, Miller said.

"We have no holdouts, no one who is against the construction. They {property owners} want it quickly," Miller added. The developers knew they would have to get agreement from all 20 property owners along the path, rather than seek condemnation power, something the General Assembly was unlikely to give them, he said.

The developers estimate the cost of building the highway at $125 million with the agreements from the landowners to dedicate the land at no cost.

The private developers would be guaranteed a "reasonable rate of return," and excess profits from the as-yet-to-be-determined tolls would go to local governments. At the end of 10 years, the developers would turn over ownership of the road to the state, under the current plan.

"I think we are pretty well on track," said state Sen. Charles L. Waddell (D-Loudoun), chairman of the Senate Transporation Committee, who introduced the legislation to allow the highway to be built privately. He noted that he had been skeptical of the plan at first, particularly since it required satisfying concerns of the transportation department.

Pethtel said that if the plan for private construction does not go through, the state will build the highway, though it would have to look at alternative routes. The private developers could build the road faster and would relieve the transportation department of having to oversee construction, he said.