On Thursday, a section of State Highway 20 north of Oak Harbor will be reduced to a single lane as a construction project continues, according to the state Department of Transportation.

The state is building a $2.5-million roundabout at the intersection with Banta Road, which is often congested with cars leaving Naval Air Station Whidbey Island by the Banta Road gate. There have also been serious accidents at the intersection in the last decade.

The state announced it will close the southbound lane as crews build the west half of the roundabout. The lane will be closed around the clock with flaggers on hand to alternative traffic through the area.

Crews will be working 20 hours a day, six days a week, but the traffic control will continue 24 hours a day during the period because of safety concerns, WSDOT communications reported.

The lane reduction is scheduled to last until June 20 at the earliest, though construction schedules are subject to change.

The city of Oak Harbor moved the city’s waterline in the area earlier this year in order to make way for the roundabout.