Roads and expressways in Chicago

Chicago's streets were laid out in a grid that grew from the city's original townsite plan platted by James Thompson. Streets following the Public Land Survey System section lines later became arterial streets in outlying sections. As new additions to the city were platted, city ordinance required them to be laid out with eight streets to the mile in one direction and 16 in the other direction. A scattering of diagonal streets, many of them originally Native American trails, also cross the city. Many additional diagonal streets were recommended in the Plan of Chicago, but only the extension of Ogden Avenue was ever constructed. In the 1950s and 1960s, a network of superhighways was built radiating from the city center. As the city grew and annexed adjacent towns, problems arose with duplicate street names and a confusing numbering system based on the Chicago River. On June 22, 1908, the city council adopted a system proposed by Edward P. Brennan; amended June 21, 1909. The changes were effective September 1, 1909 for most of the city. Addresses in Chicago and some suburbs are numbered outward from baselines at State Street, which runs north and south, and Madison Street, which runs west and east. A book was published in 1909 by The Chicago Directory Company indexing the old and new street numbers for most of Chicago. This volume is available online in PDF format indexed by initial letter, Plan of Re-Numbering, City of Chicago, August 1909. This additional paragraph explained the downtown changes: Chicago house numbers are generally assigned at the rate of 800 to a mile. The only exceptions are from Madison to 31st Street, just south of downtown. Roosevelt Road (previously Twelfth St) is one mile south of Madison with 1200 addresses to the mile, Cermak Road (previously 22nd Street) is two miles south of Madison with 1000 addresses to the mile, and 31st Street (3100 S) is three miles south of Madison with 900 addresses to the mile. South of 31st Street, the pattern of 800 to the mile resumes, with 39th Street the next major street, 47th after that, and so on. Individual house numbers are normally assigned at the rate of one per 20 feet of frontage. Thus the last two digits of house numbers generally go only as high as 67 before the next block number is reached. Higher house numbers are found on diagonal streets and have sometimes been assigned by request. The blocks are normally counted out by "hundreds," so that Chicagoans routinely give directions by saying things such as "about twelve hundred north on Western" or "around twenty-four hundred west on Division" (which both describe the intersection of Western Avenue (2400 W) and Division Street (1200 N)). South of Madison Street most of the west–east streets are simply numbered. The street numbering is aligned with the house numbering, so that 95th Street is exactly 9500 South. "Half-block" west–east thoroughfares in this area are numbered and called places; 95th Place would lie just south of(1/16 of a mile to be exact) and parallel to 95th Street, and just north of 96th Street. Every four blocks (half-mile) is a major secondary street. For example, Division Street (1200 N) is less important than either Chicago Avenue (800 N) or North Avenue (1600 N), but is still a major thoroughfare. However, this is not always the case; for example, on the city's Far North Side, Peterson Avenue (6000 N) is a more heavily trafficked street than Bryn Mawr Avenue (5600 N), which sits exactly at the 7-mile marker. U.S. Route 14 is routed along Peterson between Clark Street at 1600 W and Cicero Avenue at 4800 W, whereas Bryn Mawr is discontinuous, split into two segments in this part of the city by Rosehill Cemetery between Damen and Western Avenues. Even-numbered addresses are found on the north and west sides of a street, and odd numbers are found on the south and east sides, irrespective of the streets' position relative to the corner of State and Madison. Diagonals, even if they were to run exactly 45 degrees off of the cardinal directions, are numbered as if they were north–south or east–west streets. Examples are North Lincoln Avenue and Ogden Avenue, which bends at Madison and changes from North Ogden to West Ogden. The northernmost street in Chicago is Juneway Terrace (7800 N), just north of Howard Street. The southern boundary is 138th Street. The eastern boundary of Chicago is Avenue A/State Line Road (4100 E) along and south of 106th Street, and the furthest west the city extends is in the portion of O'Hare International Airport that lies in DuPage County, just east of Elmhurst/York Road. ==Street names==