RICHMOND, Va. - Buses and motorcoaches, both privately and publicly owned, will pay no tolls on new express toll lanes being added to the Capital Beltway in northern Virginia.

Construction of the express lanes, whose toll rate for cars and trucks will be based on the level of congestion at the time the vehicles enter the special lanes, will begin in the spring.

A spokeswoman for the project told Bus & Motorcoach News that buses, as well as passenger vehicles carrying three or more people, will pay no tolls to use the express lanes.

The public-private highway project, which has been in the planning for more than a dozen years, will cost roughly $1.7 billion - nearly double the projected cost two years ago - and will be completed in 2013, the Virginia Department of Transportation estimates.

VDOT Commissioner David S. Ekern said the agency has reached an agreement in principle with two private contractors, Transurban DRIVe and Fluor Enterprises, for design, construction, operation and maintenance of the high-occupancy-toll lanes, commonly referred to as HOT lanes.

The project is intended to reduce congestion in traffic-choked northern Virginia.

"The project has been under development since 1994, and it is time for action to bring additional congestion relief to residents, visitors and businesses in the region" said Gov. Timothy M. Kaine.

The plan calls for the private companies to build 14 miles of HOT lanes - two lanes in each direction - on the beltway. Vehicles with one or two occupants will be charged tolls based on the level of congestion.

The average toll for an auto during rush hour is expected to be $5 to $6, according to VDOT. The companies will collect the tolls and manage all operations of the HOT lanes, including repairs and maintenance, although the state will retain ownership and oversight of the lanes.

The companies also will build three new access points from the beltway into Tyson's Corner, Va., along with HOV connections from Interstate 95 to the beltway.

Early plans called for 100 percent private funding of the construction costs. However, rising costs and project upgrades will require the state to chip in about $409 million.