Originally Posted by wahooflyer
True, but the Beltway is usually jammed during daylight hours going across the American Legion Bridge from Virginia to Maryland. Because of this, I'd recommend DCA or BWI for easiest access to Rockville, unless you're heading to/from Dulles during off hours.
True, but the Beltway is also always jammed on the other side of 270 as well. I would say that it is far more likely to get stuck in jammed up traffic coming from BWI on 95 to 495 to 270 than from IAD Access road to 495 to 270.
DCA and Metro is best if where you're going is close to a station.