The lane will run along an existing carpool lane on a 14-mile stretch of southbound I-680 between Pleasanton and Milpitas. Carpools will still be able to use the lane for free.
Dave Hyams, a spokesman for the express lane project, said the project is designed to reduce congestion.
"There's capacity in carpool lanes, they're not full," Hyams said. "So this allows solo drivers the choice of using the carpool lane by paying a toll."
The toll amount will change depending on the density of traffic on the highway at the time. Signs a half-mile prior to the three access points into the lane will display the toll price, allowing drivers to choose whether it is worth it to lessen their commute time, he said.
The minimum toll will be 50 cents, with the average toll ranging from $4 to $6, Hyams said. Cars with two or more passengers won't be charged.
The express lane will operate Monday through Friday from 5 a.m. to 8 p.m., replacing the current carpool hours, which allow all drivers to use the lane in the late morning and early afternoon hours, according to Hyams.
The 14-mile stretch will be converted to an express lane over the weekend of Sept. 18 and 19, with new striping on the road to denote the entry and exit points. It will open on Sept. 20.
The FasTrak electronic toll collection system will be switched on, so drivers who want to use the lane will need a FasTrak toll tag mounted on the windshield. The California Highway Patrol will provide visual and electronic enforcement.
Toll revenue will go toward lane operation and maintenance, transit service on the Highway 680 corridor, and building future carpool or express lanes, including one on the northbound side of the highway.
Hyams said another express lane is scheduled to open next year on eastbound Interstate Highway 580 between Pleasanton and Livermore, along with a westbound Highway 580 lane in 2012.
Express lanes have operated in Southern California and elsewhere in the country, but this will be the first one in the Bay Area, Hyams said. Scott Haggerty, chair of the Metropolitan Transportation
Commission and of the joint powers authority that oversees the Highway 680 project, said in a statement, "The new express lane will be a great step forward for drivers who want a reliable trip without risking a backup."