Tolling on a portion of Interstate 66 in Northern Virginia will begin Dec. 4, officials with the Virginia Department of Transportation said Thursday.

The new tolling system will take effect on nearly 10 miles of I-66, from Route 29 in Rosslyn to the Interstate 495. The tolling will be in place weekdays only, during rush hours and in the peak direction.  As part of the transition, Virginia will extend the rush-hour periods by 90 minutes in the morning and evening, meaning that the highway will be tolled 5:30 to 9:30 a.m. in the eastbound direction and 3to 7 p.m. westbound.

The lanes will remain free to all users during  off-peak hours and weekends.

Solo drivers who are willing to pay will be able to use the lanes during the morning and afternoon rush hours, a change in a decades-long restriction to keep the peak-direction lanes open only to cars with two or more occupants. The lanes will continue to be free for carpoolers who have a toll transponder set to HOV.

Hybrid drivers, who are allowed to drive solo in HOV lanes, will lose that privilege. They will be tolled if riding alone.

Motorcycles don’t need a transponder and can continue to use the lanes for free during the tolling hours.

Users should keep in mind that tolls will be collected electronically, which means drivers need an E-ZPass, or an E-ZPass Flex if they are carpooling. The Flex pass allows drivers to use the lanes free when set on carpool mode.

Testing of the new system will continue in the next few weeks to make sure the equipment is working property, transportation officials said at a briefing with Northern Virginia leaders Thursday. Drivers will notice signs announcing the upcoming change and flashing from the toll gantries as part of the ongoing testing.

Officials say they hope the transition will help address congestion in the busy corridor and provide more options to travelers.  Part of the toll revenue will go to improvements in transit and other modes of transportation, including bike infrastructure.

“We are challenged by the need to move more people in this corridor,” VDOT Commissioner Charles Kilpatrick said.  “We have done a number of capacity projects, but the realities are we have to continue to try and find ways of moving more people and we believe this project is a way to do that.”

A good share of I-66 travelers already have E-Zpass transponders. Still, officials are urging commuters who carpool on the highway to get the Flex pass so they can continue to ride for free. When drivers pass under overhead gantries, their E-ZPass account will be debited in the amount of the trip. Drivers without an E-ZPass device will receive a bill on the mail, including a penalty for not having an E-ZPass.

“It is very important for those folks that are HOVers today that they have that flex pass,” Kilpatrick said. “That is the way the system recognizes that you have two or more in the car.”

Tolls will vary depending on traffic. The state says the requirement is to maintain a minimum average speed of 45 mph and tolls will fluctuate to control congestion to achieve that goal. There also will be no cap on tolls.