Circle Interchange
Encyclopedia
The Circle Interchange is an expressway interchange near downtown Chicago
Chicago
Chicago is the largest city in the US state of Illinois. With nearly 2.7 million residents, it is the most populous city in the Midwestern United States and the third most populous in the US, after New York City and Los Angeles...

, Illinois
Illinois
Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...

. It is the junction between the Dan Ryan
Dan Ryan Expressway
The Dan Ryan is an expressway in the city of Chicago that runs from the Circle Interchange with I-290 near downtown Chicago through the South Side of the city. It is designated as both Interstate 94 and Interstate 90 south to 66th Street, a distance of...

, Eisenhower and Kennedy
Kennedy Expressway
The John F. Kennedy Expressway is a long highway that travels northwest from the Chicago Loop to O'Hare International Airport. The expressway is named for the 35th U.S. President, John F. Kennedy. The Interstate 90 portion of the Kennedy is a part of the much longer I-90...

 expressways (Interstates 90
Interstate 90
Interstate 90 is the longest Interstate Highway in the United States at . It is the northernmost coast-to-coast interstate, and parallels US 20 for the most part. Its western terminus is in Seattle, at Edgar Martinez Drive S. near Safeco Field and CenturyLink Field, and its eastern terminus is in...

/94
Interstate 94
Interstate 94 is the northernmost east–west Interstate Highway, connecting the Great Lakes and Intermountain regions of the United States. I-94's western terminus is in Billings, Montana at a junction with Interstate 90; its eastern terminus is the U.S...

 and 290
Interstate 290 (Illinois)
Interstate 290 is a main Interstate freeway that runs westwards from the Chicago Loop. A portion of I-290 is officially called the Dwight D. Eisenhower Expressway. In short form, it is known as "the Ike" or the Eisenhower...

). The name refers to the curving ramps that appear to form concentric rings when viewed from above, and is commonly used by local traffic reporters
Traffic reporting
Traffic reporting is the distribution of information about road conditions such as traffic congestion, detours, and traffic accidents, generally as part of a radio or television broadcast program. The reports help commuters anticipate and avoid traffic problems. Many reports mention alternate...

.

The interchange is notorious for its traffic jams. In 2004, it was rated as the country's third-worst traffic bottleneck, with the drivers of the approximately 300,000 vehicles a day using it losing a combined 25 million hours.

Design

The Circle is logically a turbine interchange, with each of the four mainlines having a single entrance and exit serving both directions of the crossing highway. It does not use the quadruple-decker architecture commonly associated with stack interchange
Stack interchange
A stack interchange is a free-flowing grade separated junction between two roads.In countries where one drives on the right, left turns are handled by semi-directional flyover/under ramps...

s. Instead, it has a flattened layout, using the long, curving ramps to circumnavigate the crossing of the mainlines. This results in fewer tall bridges and gives the interchange its distinctive "circle" appearance.

Both I-90/94 and I-290/Congress Parkway have three lanes in each direction at the interchange. Each of the ramps leading to and from the freeways is one lane wide, except for the ramp from eastbound I-290 to eastbound (southbound) I-90/94; this ramp is two lanes wide.

The interchange centers on Congress Parkway (the east–west surface street that is the continuation of the Eisenhower Expressway beyond its terminus several blocks east of the interchange) and extends roughly from Halsted Street
Halsted Street
Halsted Street is a major north-south street in the American city of Chicago, Illinois.-Location:In Chicago's grid system, Halsted street marks 800 West, one mile west of State Street, from Grace Street in Lakeview south to the city limits at the Little Calumet River in West Pullman...

 on the west to Jefferson Street on the east.

History

The Circle Interchange was built in the late 1950s and early 1960s, at the same time as the construction of the Kennedy Expressway
Kennedy Expressway
The John F. Kennedy Expressway is a long highway that travels northwest from the Chicago Loop to O'Hare International Airport. The expressway is named for the 35th U.S. President, John F. Kennedy. The Interstate 90 portion of the Kennedy is a part of the much longer I-90...

.

The University of Illinois at Chicago
University of Illinois at Chicago
The University of Illinois at Chicago, or UIC, is a state-funded public research university located in Chicago, Illinois, United States. Its campus is in the Near West Side community area, near the Chicago Loop...

 is adjacent to the southwest. When the campus opened in the 1960s, it was called the University of Illinois at Chicago Circle, making it the only university in the world known to be named after a freeway interchange.

Due to its congestion, the May 2008 issue of Popular Mechanics
Popular Mechanics
Popular Mechanics is an American magazine first published January 11, 1902 by H. H. Windsor, and has been owned since 1958 by the Hearst Corporation...

listed the Circle Interchange among their list of The 10 Pieces of U.S. Infrastructure We Must Fix Now.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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