The Beltway is
notorious throughout most of
Maryland and
Virginia for horrendous traffic jams, high
traffic volumes even when moving, and general unfriendliness to visitors. It is designated as
Interstate 495 through its length, but its southeastern
half also carries
Interstate 95 around
Washington.
One common problem to all beltways is how to designate directions -- if you're driving in a circle (actually, it's more approximately an oval), your direction will change N/E/W/S as you continue around the loop. The only consistent markings that can be used are Inner Loop and Outer Loop, designating which side is closer to or further from the center city. (For example, on the southern side of the city, eastbound lanes are the Outer Loop, and westbound are the Inner Loop; the situation is reversed on the northern side.)
River crossings are a major problem in the Washington area. The Woodrow Wilson Bridge on the southeastern side of the Beltway is old and decrepit, in addition to being a drawbridge and thus subject to a full stop whenever large ships must pass through; the American Legion Bridge to the northwest is simply way over capacity because of suburb-to-suburb commuting to the Dulles Toll Road (VA) and Interstate 270 (MD) technology corridors.