The second of six interchanges being built under a private-public partnership on busy Route 28 was scheduled to open to traffic this weekend at Route 606/Old Ox Road.

The interchanges are part of a $200 million project to replace six of the 10 traffic lights that cause bottlenecks between Interstate 66 and Route 7. Business and commercial property owners in the Route 28 area will pay more than $130 million toward the project through a special tax, and the Virginia Department of Transportation will pay the rest.

"With the partnership between the county, state and the private sector, we're working to make Route 28 one of the most vibrant economic corridors in the area," Supervisor D.M. "Mick" Staton Jr. (R-Sugarland Run), chairman of the Loudoun board's transportation committee, said at a ribbon-cutting ceremony Thursday.

The former intersection of Route 28 and 606 is now a full cloverleaf interchange, with a four-lane bridge carrying Old Ox Road over Route 28.

Five of the eight new interchange loops were scheduled to open to traffic this weekend: northbound 28 to eastbound 606, southbound 28 to eastbound and westbound 606, and eastbound 606 to northbound and southbound 28. The three other ramps are scheduled to open early next year.

VDOT said more than 90,000 vehicles a day travel on Route 28 and 20,000 on Route 606. With the opening of the $24.9 million interchange, the average vehicle delay at the traffic signal will be reduced from two minutes to about 30 seconds, officials said. The traffic light will be removed in early 2005 when the remaining loops and ramps are completed.

The first of the six interchanges opened Dec. 5 at Barnsfield Road to carry traffic into the new Smithsonian Air and Space Museum annex near Dulles International Airport. Construction has begun on two other interchanges, at Waxpool Road and Westfields Boulevard, and is scheduled to begin next summer at McLearen Road and Sterling Boulevard. Stoplights will remain at Nokes Boulevard, Innovation Avenue, Willard Road and Frying Pan Road.

The interchanges are being built under the Public-Private Transportation Act of 1995, which allows private construction companies to propose ways to design and build a transportation project if they can find the funds. In this case, Clark Construction Group Inc. and its road-building subsidiary, Shirley Contracting, proposed to build the interchanges using a combination of state money and a special property tax.