Updated at 7:40 p.m.
The George Washington Parkway has reopened after a crash near Slaters Lane in Alexandria closed the northbound lanes.
Though Park Police initially reported that three or four cars were involved in the collision, a dispatcher said after the scene had been cleared that only two cars were involved. She said that the cause was not clear, and no one was injured.
An earlier dispatcher said that one car caught fire. An Alexandria police captain said on Twitter that the occupants of the car that caught fire had escaped.