The state Department of Transportation has named Northwest Express Roadbuilders as the leading bidder to design and construct the largest transportation project in Georgia history. The Northwest Corridor project is expected to build optional toll lanes along I-75 and I-575 in Cobb and Cherokee counties.

The team still has to make it through final negotiations to sign the contract this fall.

Northwest Express Roadbuilders includes Archer-Western Contractors, of Atlanta, Hubbard Construction Company of Winter Park, Fla., and the engineering firm Parsons Transportation Group of Pasadena, Calif. They bid $599 million for their portion of the work, shaving perhaps $100 million off the DOT’s estimated project cost. The total cost of the remaining work on the project is now estimated at $840 million.