If you’re driving on Interstate 66 inside the Beltway and see some flashing lights as you’re passing through toll gantries, don’t worry: it’s just a test. For now.

The Virginia Department of Transportation (VDOT) is conducting field testing of the electronic tolling equipment for the I-66 Inside the Beltway program to ensure the system is fully functional when tolling begins in December during weekday, rush-hour periods. Testing will continue through the remainder of the summer and fall.

No tolling will occur until the rush-hour-only Express Lanes open, VDOT said.

Crews are testing cameras, E-ZPass readers, new electronic toll signs and indicator lights that flash when a vehicle is traveling with an E-ZPass Flex in the HOV mode. This feature will be used for HOV enforcement once the Express Lanes are operational.

Dynamically-tolled Express Lanes are scheduled to open in December on the nine-mile stretch of I-66, from I-495 to U.S. Route 29 in Rosslyn. Solo drivers will have the option to use the lanes during weekday peak periods. Vehicles with two or more people can continue to use the lanes for free. All vehicles traveling during these periods will need an E-ZPass transponder, and HOV-2+ vehicles will need an E-ZPass Flex transponder switched to HOV-mode to travel for free.

Once open in December, the 66 Express Lanes Inside the Beltway will be effective from 5:30 to 9:30 a.m. eastbound and from 3 to 7 p.m. westbound during the weekdays. The lanes will remain free to all users during the off-peak periods, including weekends.

The 66 Express Lanes Inside the Beltway will open as HOV-2, but will switch to HOV-3 when the 66 Outside the Beltway Express Lanes open in mid-2022, matching the current HOV rules on I-495 and I-95 Express lanes.

More information can be found at Transform66.org.