Interstate 66 westbound is scheduled to close at Route 267 overnight Monday due to work on the Metrorail extension to Dulles airport and Loudoun County.
Officials said the work is on the bridge that will carry trains above the highway, but vehicles are not allowed to travel beneath the structure while that occurs due to safety reasons.
The lanes are scheduled to close at 11 p.m. and reopen by 5 a.m. Tuesday.
Traffic will be detoured on to the Dulles Connector Road westbound, then to the Capital Beltway north, to a U-turn at Georgetown Pike to south on the Beltway. Drivers can then rejoin I-66.
Flaggers and police will be onsite, officials said.
Follow me on Twitter: @michaelbolden.