<P> Historically, the Chicago Skyway was signed as, and was widely considered to be part of, I - 90 from the mid-1960s forward (after I - 90 in this area had been swapped with I - 94). However, around 1999, the City of Chicago realized they had never received official approval to designate the Skyway as I - 90 . The city subsequently replaced most of the "I - 90" signage with "TO I - 90 / I - 94" signage . However, the Illinois Department of Transportation (IDOT) has always and continues to report the Skyway as part of the Interstate Highway System, and the Federal Highway Administration also considers the Chicago Skyway an official part of I - 90 . </P> <P> The Skyway's official name, referring to it as a "toll bridge" rather than a "toll road", is the result of a legal quirk . At the time of its construction, the city charter of Chicago did not provide the authority to construct a toll road . However, the city could build toll bridges, and it was found that there was no limit to the length of the approaches to the bridge . Therefore, the Skyway is technically a toll bridge with a six - mile - long (9.7 km) approach . This also is part of the reason that there are no exits available until after one has crossed the bridge and paid the toll . </P> <P> Along the Jane Addams Tollway, there are four mainline toll barriers in each direction--two split plazas and two full plazas . The barriers are located around the O'Hare International Airport area (River Road eastbound and Devon Avenue westbound), in Elgin, near Marengo (eastbound), in Belvidere (westbound), and in South Beloit . I - 39 travelers exiting or entering at Rockford paid at the Cherry Valley toll plaza, but that toll plaza has been decommissioned southbound in 2003 and northbound in 2004 due to traffic congestion . </P> <P> In February 2006, the Marengo westbound and the Belvidere eastbound toll plazas were removed . Two two - toll plazas near O'Hare and the one in Elgin each charge cash tolls of $1.50 (as of January 1, 2012) and I - Pass tolls of 75 cents for a two - axle passenger vehicle . The South Beloit toll plaza near the Illinois and Wisconsin state line is $1.90 and 95 cents for I - Pass users (formerly $1.00 and 50 ¢ before 2012). Eastbound traffic does not pay a toll at Belvidere because of the removal of the eastbound Belvidere plaza, but pays $3.00 at Marengo (I - Pass users pay $1.50). On the other hand, westbound traffic pays no toll at Marengo but pays $3.00 at Belvidere (I - Pass users pay $1.50). This change was done to accommodate open road tolling construction . Originally, a ticket system was used to compute tolls on the segment between Beloit and Elgin with each driver receiving a Hollerith card upon entering and paying upon exiting, but it was replaced with a cash barrier system in the late 1970s . It was the only portion of the Illinois Tollways to use a ticket system . </P>

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