From a press release: 

Crews are using opportunities between rush hours today and Friday, while temperatures are favorable, to treat roads with anti-icing materials in northern Virginia in anticipation of potential winter weather during the Friday afternoon rush hour and on Saturday. Drivers are encouraged to monitor the National Weather Service’s forecast by visiting weather.gov.

A portion of the congested Fairfax County Parkway, which was once planned as an outer beltway for Washington, D.C., will be widened to six lanes.

The Virginia Department of Transportation plans to widen about five miles of the parkway between Routes 123 and 29. Additionally, an interchange will be added at Popes Head Road, where today a signal light causes major backups during the morning and afternoon commutes.