World Library  
Flag as Inappropriate
Email this Article

Illinois State Highway System

Article Id: WHEBN0042579841
Reproduction Date:

Title: Illinois State Highway System  
Author: World Heritage Encyclopedia
Language: English
Subject: List of U.S. Highways in Illinois, List of Interstate Highways in Illinois, Illinois Route 22, Illinois Route 10, Illinois Route 120
Publisher: World Heritage Encyclopedia

Illinois State Highway System

State Highway System
Interstate 39 markerU.S. Route 20 markerIllinois Route 59 markerChicago Skyway marker
Highway markers for Interstate 39, U.S. Route 20, Illinois Route 59 and the Chicago Skyway
Overall map of system: freeways in light blue, tollways in green, other highways in yellow
System information
Maintained by IDOT, ISTHA, and SCC
Formed: November 5, 1918 (1918-11-05)[1]
Highway names
Interstates: Interstate X (I-X)
US Routes: U.S. Route X (US X)
State: Illinois Route X (IL X)
System links
Illinois State Highway System

The organized State Highway System of the U.S. state of Illinois comprises all of the state routes in the state.

Illinois Highway Code

The Illinois Highway Code (605 ILCS 5) states that all state highways are to be numbered, and that no state highway shall go unnumbered.[2] In addition, roads in the system include state highways that connect

Descriptions of each individual state highway are filed with the county clerk of the county in which the state highway resides.[4] State highways may be maintained by either the municipalities if within a municipality, or the Illinois Department of Transportation.[5] Should a highway run through a municipality, IDOT is authorized to choose a route through the municipality in order to make a route contiguous for through traffic.[6]


The State Highway System was created in 1918 with the first State Bond Issue (SBI) Routes, 1 through 46. Bonds were floated to pay for specific routes. SBI # 1 paid for Route 1, and so on. These initial 46 route numbers marked the major infrastructure roads desired by the state legislature in 1918. Remarkably, many of these numbers still exist on the original or nearby alignment. As the highway system grew these numbers were altered to accommodate new roads or extensions of older roads.

In 1924, additional State Bond Issues were authorized for SBI Routes 47 through 185. These route numbers were originally assigned and grouped to specific regions of the state. Thus, it is not uncommon to find groups of routes with similar numbers around each other (routes 23, 26, and 29 are found in north-central Illinois, while routes 53, 56, 58, 59, 60, 62, 64, 68 and 72 are all be found in northeastern Illinois and routes 100, 101, 103, 104, 105, 107 are found in western Illinois west of the Illinois River and largely south of McDonough County line.

SBI Route numbers that were superseded by other routes, US or state routes were often reused. For example, SBI Route 61 was originally assigned to a road segment in northeastern Illinois, but was reassigned to a route in western Illinois, sometime after 1937.

Illinois Route 72 cross-sign mounted on a stoplight in Hoffman Estates

SBI Numbers are still used for several purposes, even when they do not match the posted number. IDOT District maps still refer to SBI numbers on the various roads it maintains, along with other non-posted designations that refer to how the route was authorized. Bridge weight plates refer to SBI numbers instead of posted route numbers as well. For example, bridge plates along old US-66 refer to the route as "SBI-4"

When the United States Numbered Highway System was started in 1926, the US numbers were just tacked onto the existing IL/SBI number unless the US Route was routed along a new route.

See also


  1. ^
  2. ^ 605 ILCS 5/4-201.11
  3. ^ 605 ILCS 5/4-201.5
  4. ^ 605 ILCS 5/4-204
  5. ^ 605 ILCS 5/4-203, 605 ILCS 5/4-208
  6. ^ 605 ILCS 5/4-205

External links

  • 605 ILCS 5/Illinois Highway Code
  • Illinois Department of Transportation
  • Illinois Highways Page
  • Road Signs of Illinois
  • Illinois State Highway Endpoints
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.