Editing Multilevel streets in Chicago (section)

==History==
[[Image:Michigan Avenue bridge over Chicago River.jpg|thumb|250px|The [[Michigan Avenue Bridge]] crossing the [[Chicago River]]]]
The multilevel configuration arose from geography and [[traffic]] patterns in [[Chicago Loop|the Loop]]. In most other parts of the rest of the city near the Chicago River, only major streets crossed the river. However, most downtown streets crossed the river, and all of these crossings were [[bascule bridge]]s, which required [[Loading gauge|height clearances]] at the approaches to and over the river. Clearances were further necessitated due to the presence of many existing [[Rail tracks|railroad tracks]] along the river (as in the west bank of the south branch) and tracks that ended at the river (such as the tracks ending at [[Randolph Street (Chicago)|Randolph Street]]).<ref>{{cite encyclopedia|url=http://www.encyclopedia.chicagohistory.org/pages/10909.html|title=View Eastward along Chicago River, toward Wacker Drive and Michigan Avenue, 1931|access-date=August 2, 2007|date=2005|publisher=Chicago Historical Society|encyclopedia=The Electronic Encyclopedia of Chicago}}</ref> Thus, a clearance zone was created along the river at locations that contained many closely spaced crossings. Many double-decked or triple-decked streets were created because they fell within this clearance zone.

This also created an anomaly not only in the layout and uses of streets, but also planning of buildings. Generally, the upper levels of the multi-level streets usually serve local traffic. The primary entrances of buildings are usually located on this level. The lower levels generally serve through-traffic and trucks serving businesses along the roads. This level houses the receiving/shipping entrances to the buildings on these streets. As a result, loading docks at street level are noticeably absent.

The first raising occurred from 1855 to 1858, when streets and buildings [[Raising of Chicago|were raised]] between four and seven feet above their former elevation, just a few feet above [[Lake Michigan|lake]] level, where they were constantly muddy. The higher elevation allowed for [[sanitary sewer|sewer]]s and proper [[drainage]].<ref>{{cite web|url=http://www.encyclopedia.chicagohistory.org/pages/1202.html|access-date=February 20, 2008|publisher=Encyclopaedia of Chicago|title=Street Grades, Raising}}</ref> However, this did not produce any two-level streets; the first of those was [[Michigan Avenue (Chicago)|Michigan Avenue]] in the late 1910s. When the [[Illinois Center]] development was built on the east side of downtown, a new upper level was built, making most streets in that area three levels.

After about 1890, [[Advocacy groups|special interest group]]s, including recreational bicyclists, farmers delivering harvested crops to market, and motorists, began to mount support for [[Pavement_%28material%29#Concrete_paving_.28white_paving.29|concrete paving]] to replace the previously common [[dirt road]]s.  Public road planning in Chicago began in 1910 when the [[Chicago Plan Commission]] was created to implement [[Daniel Burnham]] and [[Edward H. Bennett|Edward Bennett's]] plan.<ref>{{cite encyclopedia|url=http://www.encyclopedia.chicagohistory.org/pages/1209.html|title=Streets and Highways|access-date=August 6, 2007|date=2005|publisher=Chicago Historical Society|encyclopedia=The Electronic Encyclopedia of Chicago}}</ref>

The double-decked portion of [[Wabash Avenue (Chicago)|Wabash Avenue]] north of the Chicago River was built in 1930, in conjunction with the single-level [[Wabash Avenue Bridge]]. On January 3, 2005, the upper and lower levels were closed at [[Kinzie Street (Chicago)|Kinzie Street]] for reconstruction (in conjunction with the [[Trump International Hotel and Tower (Chicago)|Trump Tower Chicago]] development) but have since been reopened.

The city's famed [[Billy Goat Tavern]], immortalized by [[John Belushi]] in a ''[[Saturday Night Live]]'' sketch as the [[Olympia Cafe]],<ref>{{cite web|url=http://www.frommers.com/destinations/chicago/D31548.html|access-date=August 2, 2007|date=2007|publisher=Wiley Publishing, Inc.|work=Frommers.com|title=Billy Goat Tavern}}</ref> is located on the lower level of Michigan Avenue.