Interstate 495 (Capital Beltway)

From Wikipedia, the free encyclopedia

The Capital Beltway (in green)

Interstate 495 (abbreviated I-495) is a freeway-class interstate highway which circles Washington, D.C. and its inner suburbs in Maryland and Virginia. I-495 is widely known as the Capital Beltway or simply as the Beltway, especially when the context of Washington, D.C., is clear. It is the basis of the phrase "inside the Beltway", used when referring to issues dealing with American government and politics. Interstate 95 utilizes the southern and eastern half of the Capital Beltway to circumnavigate Washington, D.C., and is cosigned with Interstate 495 along that route.

[edit] History

The federal government gave final approval for the construction of the Capital Beltway (also known as the Circumferential Highway in the planning stages) on September 28, 1955. The first section of the 64-mile long Beltway (including the Woodrow Wilson Memorial Bridge over the Potomac River) was opened on December 21, 1961; the highway was completed on August 17, 1964.

Originally designated I-495, in 1977 the eastern portion of the Beltway was re-designated I-95 when a proposed alignment of I-95 from New York Avenue in Washington, D.C., through Prince George's County, Maryland to I-495 was cancelled. Motorists never fully adjusted to the two halves of the Beltway having different numbers. According to Ron Shaffer of the Washington Post, "There were signs stating that to continue on the Beltway, you had to get off at the next exit, when all you really had to do was keep going straight. Lots of resistance from bureaucrats, but eventually we got dual I-95/I-495 signs on the eastern half of the Beltway."[1] So in 1989 the I-495 designation was restored to the eastern portion, making it a dual I-95/I-495.

Traveling clockwise, the Beltway is designated as the Inner Loop; traveling counter-clockwise, it is designated as the Outer Loop. This parlance too has led to its own confusion, with unfamiliar motorists imagining two separate, distinct highway alignments, one some distance inside the other. At entrance ramps to the Beltway and on the on-highway signage, "Inner Loop" and "Outer Loop" shields are posted in conjunction with the route marker shields, although the terms are not emphasized in signage.

The Beltway crosses the Potomac River twice, on the Woodrow Wilson Memorial Bridge and on the American Legion Memorial Bridge.

[edit] Traffic congestion

Traffic volume on the Beltway can be as high as 225,000 vehicles per day. Despite numerous widening projects during its history, heavy traffic on the Beltway is a continuing problem.

Two intersections on the Capital Beltway are ranked in the top 20 on a study of the "worst bottlenecks in the nation." They are the I-495 at I-270 interchange in Montgomery County, Maryland, ranked third overall, which receives 243,425 cars daily, and the I-495 at I-95 interchange in Prince George's County, Maryland, ranked 11th, with 185,125 cars. The Springfield Interchange, where I-395, I-95, and I-495 meet, was previously ranked fifth worst in the nation, but recent improvements have taken it off the top 20. Local commuters refer to the Springfield Interchange as "The Mixing Bowl," although this designation is reserved by highway officials for the even more complicated interchange complex adjacent to the The Pentagon on the original Henry G. Shirley Memorial Highway (currently better-known as Interstate 395) at State Route 27 in Arlington. See Pentagon road network for more information on the true Mixing Bowl.

In April 2005, the Virginia Department of Transportation signed an agreement with two private companies to build high-occupancy toll lanes on the stretch of the Beltway between Springfield and Georgetown Pike. Maryland officials are considering such lanes on their segment of the Beltway, as well as other major commuter highways in the state. Locals who disapprove of these projects have nicknamed them "Lexus Lanes" because of the potential high price for using the lanes in exchange for by-passing congestion. These new lanes are one stage of a controversial project to widen the beltway, with the second stage would involve widening the beltway to 12 lanes; opponents have called for various alternatives to this project (as well as the controversial Intercounty Connector project), like the Bi-County Transitway. [2]

[edit] Capital Beltway trivia

The circumferential roadway is located not only in the states of Virginia and Maryland, but also crosses briefly through the District of Columbia over the Potomac River on the Woodrow Wilson Bridge. [3]

The Capital Beltway also interchanges with a "secret" unsigned section of the Interstate Highway System, the long lost Interstate 595 in Maryland, completed in 1995. This roadway is still signed as U.S. Highway 50. [4]

Exit numbers on the Beltway have gone through several iterations. Originally, all exits on the Beltway were numbered sequentially in a clockwise direction, starting with exit 1 for US 1 in Alexandria. After the eastern half of the Beltway was renumbered in 1977 as Interstate 95, exits on the Maryland portion were renumbered to the current format, counterclockwise with exit numbers assigned to mileposts. This caused problems because there were some exits that had the same number in Maryland and Virginia. Around 2000, this problem was solved by renumbering all of the Virginia exits. The exit numbers between the American Legion Bridge and the Springfield Interchange--Interstate 495's intersection with Interstate 395 and Interstate 95 in Virginia--became a continuation of the Maryland exit numbers from the Woodrow Wilson Bridge to the American Legion Bridge. The exit numbers between the Springfield Interchange and the Woodrow Wilson Bridge became a continuation of the exit numbers of Interstate 95 in Virginia.

[edit] Exit list

Exits are numbered in a counterclockwise (outer loop) direction, which would be the opposite of AASHTO guidelines. However, the normal standard is overriden due to the presence of Interstate 95, which proceeds northward on the outer loop. Being a main interstate, its number sequencing (south-to-north numbering, which is in accordance with AASHTO guidelines) takes precedence, and the remaining exits are adjusted to conform.

[edit] See also

• Inner Loop, a partly-built downtown loop
• Washington Outer Beltway, a planned loop outside the Beltway
• Intercounty Connector, a piece of the Outer Beltway
• Springfield Interchange, the complicated interchange of the Beltway, Interstate 95, and Interstate 395 in Springfield, VA.

[edit] External links

• Official Study Website published by the Maryland State Highway Adminsitration
• Capital Beltway (I-495 and I-95), by Roads to the Future
• Steve Anderson's DCroads.net: Capital Beltway (I-495 and I-95)
• "Memory Lanes": 40th anniversary of the Beltway's opening (Washington Post)