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The 23 interstate highways that crisscross Illinois are all linked to the 13 Illinois interstates that carry traffic across Illinois borders into surrounding states and on throughout the country via the national interstate system.

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Table: Illinois Interstate Highways- starting and ending points and total miles.

Illinois, with 2,169.53 miles of interstate highways, ranks third in the nation in interstate miles; only Texas (3,233.45 miles) and California (2,455.74 miles) rank ahead of the Land of Lincoln. In Illinois, over 29 percent of all public travel is done via the interstates and over 60 percent of all truck travel.

The busiest segment of the Illinois interstate system in 2004 was along Interstate 90/94 (the John F. Kennedy Expressway in Chicago) just north of Chicago Avenue, where an average of 332,400 vehicles use the highway daily. The least traveled Illinois interstate was Interstate 180 in Bureau County, which carries an average of 2,000 vehicles daily. Return to Top


The State of Illinois and the Illinois Department of Transportation are exceptionally proud of the unique pioneering roles Illinois has played in the evolution and development of the Dwight D. Eisenhower Interstate Highway System. Indeed, Illinois has produced a number of interesting “Interstate Legacies.” Three of them will be described in this section.


Among Illinois’ most unique interstate legacies was that the Land of Lincoln was the host state and site for one of the most important and comprehensive research projects ever undertaken in the field of highway design and construction practices.

In 1951, the American Association of State Highway Officials (AASHO) concluded that a comprehensive, truly scientific research effort was needed to establish pavement design standards and guidelines for the roads and bridges of the future. A Road Test Advisory Committee was established that same year and went to work on designing the research and selecting a site where it would be conducted.

The site the Committee chose in 1952 was just west of Ottawa, Illinois in LaSalle County. The site met requirements for temperature, frost penetration and soil conditions and was representative of conditions underlying roads in a good portion of the country.

PHOTO: AASHO Road Test Site under construction, 1956-58. Courtesy of the Transportation Research Board, Washington, D.C.

The test pavements were constructed in six loops along an 8-mile section of where Interstate 80 now exists between Utica and Ottawa, Illinois. Loop one, which was used to test the effects of weather on pavement is still visible from eastbound Interstate 80. ILLUSTRATION: Test Site Area Diagram. Courtesy of the Transportation Research Board, Washington, D.C.

The purpose of these tests was to study pavement and bridge structures of known construction and design under moving loads of known weights and frequency. The tests were conducted by running trucks with loads of different weights and load distributions repeatedly on road sections constructed with varying types of designs, bases, sub-bases and thickness. The actual testing began in October of 1958. A fleet of 70 to 126 vehicles of varying sizes and weights were driven by Army personnel continuously between 18 and 19 hours a day, six days a week, over the test sections of pavement and bridges. Close to 320 Army personnel were utilized at the peak of the project. 141 accidents and two driving fatalities occurred during the two-year test period.

Driving on the test site road was concluded in November of 1960. The AAHSO Road Test of 1958-1960 “paved the way” for subsequent pavement research and standards development efforts. As testimony to the AASHO Road Test’s importance, the Smithsonian Institution’s National Museum of American History is planning on housing the road test research materials and artifacts in its Archives Center in Washington, D. C., where they will eventually be made available for examination. (SMITH / ZIMMERMAN / FINN AND MASON.) PHOTOS: Left: A small truck turning on the loop. Right: U. S. Army Troops washing trucks at the test site. Courtesy of the Transportation Research Board, Washington, D.C.

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Another of Illinois’ pioneering interstate legacies is also one of the state government’s most popular and lauded programs, the IDOT “Minutemen,” or the Emergency Traffic Patrol (ETP) program. The ETP program dispatches teams of emergency patrol vehicles and drivers to traffic disruptions and potential safety problems caused by accidents, disabled vehicles, or hazardous debris on high-traffic volume segments of the Illinois interstate system.

Today, this is an integral part of keeping traffic flowing on congested roadways but in 1960, the idea of an ETP program was new and untested before Illinois launched its pilot program. Prior to that time, when an accident occurred or a vehicle was disabled, it was more or less up to the motorist (or responding law enforcement personnel) to make arrangements for private tow trucks or others to come to the accident scene or to the assistance or the motorist experiencing vehicle problems. Response times were often slow, resulting in traffic jams in cases where the accidents blocked the roadway, which increased the danger to drivers and passengers in disabled vehicles regardless if they were in the traffic lanes or on safety “shoulders.” Further snarling traffic would be the development of so-called “gapers’ blocks,” where motorists passing a crash scene or disabled car would slow down to observe the situation. The longer such scenes lasted, the more they increased the potential for congestion and accidents behind or upstream from the original incident location. While these situations always posed traffic flow and safety problems, they could create chaos and gridlock during peak travel periods, or “rush hours.”

In late 1960, a decision was made to open a segment of the Congress Street Expressway (now I-290, the Eisenhower Expressway) to traffic despite the fact that the roadwork was not fully completed. The work yet to be finished was the paving of the safety shoulders. In one location the drop off from the pavement to the shoulders was at least 8 inches. Since the shoulders were not available for disabled vehicles to seek refuge on, they would remain in the through traffic lanes and could create traffic jams of monumental proportions.

To address this situation, it was decided that the state should, temporarily, field a small number of vans or trucks to patrol along the “still under construction zone.” The task of the original ETP vehicles and their crews was to keep the traffic lanes clear. They were simply equipped; with radiotelephones, extra warning lights, road flares, barricades, reinforced “push” bumpers and tanks of compressed air. The air for inflating flat tires enough to enable the cars to be driven off the mainline lanes onto ramps. The idea was that upon encountering a disabled vehicle or accident scene, the responding unit would push the staled vehicle from the roadway or remain to protect the scene until a private tow truck could be summoned. The program was an immediate success; generating hundreds of complimentary letters to the state highway department about it and its workers … a welcome and unusually positive response.

Early in 1961, a proposal was made by Chicago area state highway officials to make the program permanent and expand it to other, heavily traveled parts of the Chicago expressway network. The novel idea met with some opposition from a few highway officials who thought that such a service was not a proper function for a public highway agency. The proposal’s advocates’ arguments prevailed and a total of $1.5 million was approved to get the program up and running. PHOTOS: Left: An early “Minuteman” in military style uniform beside light truck. Right: Three ETP program trucks righting an overturned truck on the Chicago Expressway System. Courtesy of IDOT Emergency Traffic Patrol Program Office, Chicago.

The ETP program’s success was (and remains) the subject of very favorable press and media coverage. One of the earliest and most ardent fans of the program was the late Erv Hayden, a Chicago Police Sergeant who provided traffic reports from a helicopter and which were broadcast over Chicago radio station WGN. Hayden, who also appeared on his own traffic safety show on WGN ‘s television station on Saturday mornings, featured the ETP program on at least two of his TV broadcasts.

It was Hayden who was responsible for naming the patrol, “The Minutemen.” He had noted that, from his helicopter, that whenever there were accidents or other problems on the expressways, it always seemed that an ETP vehicle was on the scene “within a minute.” PHOTO: Department of Public Works and Buildings Director Francis G. Lorenz (second from left) and George March (second from right) are shown with two Division of Highways “Minutemen” displaying the new “Minutemen” patches. Courtesy of IDOT Emergency Traffic Patrol Program Office, Chicago.

During the latter half of 1961, the ETP responded to a total of 4,150 incidents, or “assists.” In 1962, it’s first full year of operation, 18,736 assists were recorded. By 1985, that number had swelled to over 107,000. From its inception through 2004, the ETP Program in the Chicago Metropolitan area has assisted 3,389,655 motorists.

PHOTO: IDOT Emergency Traffic Patrol “Minuteman” assisting Motorist. Illinois Department of Transportation Slide Collection.

PHOTO: One of the military surplus heavy tow trucks obtained for the ETP program and four ETP personnel. Courtesy of IDOT Emergency Traffic Patrol Program Office, Chicago.

PHOTO: One of the more modern, custom-designed ETP large tow trucks that replaced the military surplus vehicles used in the early days of the program. Courtesy of IDOT Emergency Traffic Patrol Program Office, Chicago.

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Another area where Illinois’ pioneering ways affected the interstate highway system program was its 1958 “first-in-the-nation” inclusion of rapid transit rail lines in the median of a Chicago expressway.

The first superhighway, or “expressway” planned for inside the Chicago City Limits was the West Side Highway, which was to stretch from Downtown Chicago through the city’s West Side and beyond into its western suburbs. With much of the planned route’s alignment running along Congress Street in Chicago, the highway soon became known as the Congress Street Expressway.

In order to build the expressway along that route, it would be necessary to demolish or relocate the Garfield Park branch of the old Metropolitan elevated rapid transit line. The line was also used by the Chicago, Aurora and Elgin interurban electric railroad to transport commuters from the western suburbs into Chicago’s “Loop,” or downtown central business district.

West Side and near west suburban residents still needed and demanded mass transit service and the option of not replacing the link to downtown Chicago was never seriously entertained. Instead, the next most logical alternative seemed to be to run a rapid transit line parallel to, or in the median of, the new expressway.

The decision was made by the City of Chicago in 1955 to build a completely new rapid transit line in the median strip of the Congress Street Expressway. PHOTO: Newly elected Chicago Mayor Richard J. Daley at groundbreaking ceremony for the CTA Rapid Transit Line in the median of the Congress Street Expressway (Now I-290 / Eisenhower Expressway) Chicago, 1955. America on the Move Exhibition, Photo No. 533. Courtesy of the Chicago Transit Authority. National Museum of American History. Smithsonian Institution, Washington, D. C.

Given the background, the first instance of placing mass transit in an expressway median was not so much an innovation in mass transportation as it was the easiest way out of a seemingly unavoidable and perplexing political problem. It was almost an afterthought. Whatever its genesis, the idea was popular and the Chicago Transit Authority (CTA) and the City of Chicago celebrated the opening of the new “West Side Subway” line on June 22, 1958.

As a result of its popularity, the designs and layouts of certain other Chicago expressways included provisions for future median rail rapid transit lines. The first of the “second generation” of the median lines to open was one in the middle of Interstate 90/94 (the Dan Ryan Expressway) on the city’s South Side. The Dan Ryan Line opened on September 28, 1969 and carried riders from 95th Street (U.S.12/20) to and from Downtown Chicago. Less than a year later, on February 1, 1970, service on the Logan Square Line was extended to Jefferson Park on the City’s Northwest Side using the median of Interstate 90/94, The John F. Kennedy Expressway. Fourteen years later, in 1984, the line from Jefferson Park was extended to O’Hare International Airport, creating a direct rapid transit link between the bustling airport and downtown Chicago.

Read “The Long Road to the Interstates of Illinois” in the Interstate Stories Section of this Website.

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Interstate 50th Anniversary

Friends of the Interstate
The Eisenhower Interstate System
Illinois Interstates
IL Celebration Theme
Photo Album
The First 50 Years Video Presentation
Illinois' Historic Lincoln Highway
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Eisenhower & The 1919 Convoy
The 2006 Convoy & Special Events
Interstate Stories
References & Resources
The Interstate Quiz
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