Interstate 55 (I-55) is a major north–south Interstate Highway in the US state of Illinois that connects St. Louis, Missouri, to the Chicago metropolitan area. It enters the state from Missouri near East St. Louis, Illinois, and runs to U.S. Route 41 (US 41, Lake Shore Drive) near Downtown Chicago, where the highway ends, a distance of . The road also runs through the Illinois cities of Springfield, Bloomington, and Joliet. The section in Cook County is officially named the Stevenson Expressway, and in DuPage County its officially named the Joliet Freeway or the Will Rogers Freeway. The section from the south suburbs of Chicago to the area near Pontiac is officially named the Barack Obama Presidential Expressway after the 44th President, Barack Obama, who launched his political career from Illinois.
Route description
I-55 within Illinois carries heavy traffic, with an average of more than 20,000 vehicles per day for most of its length. Significant portions of I-55 contain six lanes (three lanes in each direction) and are heavily used by commuters. I-55 in Illinois begins in East St. Louis on the Poplar Street Bridge over the Mississippi River at the Missouri state line and runs southwest to northeast through the state, ending in Chicago at US 41 (Lake Shore Drive). Along the way, it goes through four metropolitan areas in the state: the Illinois portion of the St. Louis metropolitan area, the Springfield metropolitan area, the Bloomington–Normal metropolitan area, and the Chicago metropolitan area (also known as Chicagoland).
East St. Louis to Springfield
I-55 enters Illinois on the Poplar Street Bridge from Missouri, running concurrently with I-64 and US 40. The highway meets Illinois Route 3 (IL 3) at a series of complex interchanges. IL 3 joins I-55/I-64/US 40 for approximately . Still in East St. Louis, I-64 and IL 3 leave I-55/US 40, while the current routing of I-70 joins the pair. The three routes continue north-northeast, intersecting the southern terminus of IL 203 near Granite City, IL 111 near Fairmont Park, I-255 and IL 157 in Collinsville, and IL 159 in Maryville.
Approximately after the IL 159 interchange, US 40 leaves I-55/I-70. After an interchange with IL 162 in Troy, I-70 heads east toward Effingham. At the same interchange, I-270 intersects I-55 and ends. On its way further north, I-55 intersects IL 143 near Edwardsville, IL 140 in Hamel, IL 4 south of Livingston, local roads that connect to Livingston and Staunton, and IL 138 near White City. About further north, I-55 intersects IL 16 at a larger interchange to the west of Litchfield. It then goes another before meeting the eastern terminus of IL 108 to the east of Carlinville. Continuing along, it meets the southern and northern termini of IL 48 and IL 127 west of Raymond, local roads to Farmersville and Divernon, IL 104 near Auburn, and two local roads to Glenarm and Chatham. At the East Lake Drive interchange, I-55 crosses over Lake Springfield into Springfield proper.
Springfield to Bloomington
I-55 enters Springfield at an interchange with Toronto Road. About further north, it meets I-72 and US 36 to form a concurrency that skirts the southern and eastern edges of the city. At the same interchange, it meets the southern end of I-55 Business (I-55 Bus.). I-55/I-72/US 36 has two interchanges while on the concurrency: Stevenson Drive/East Lake Drive and IL 29. north, I-72 and US 36 head east toward Decatur and Champaign. At this interchange, I-55 intersects IL 97, which leads to downtown Springfield. I-55 then crosses the western terminus of IL 54 (old US 54). further north, it meets the northern terminus of I-55 Bus., effectively leaving Springfield.
From Springfield to Chicago, I-55 follows a northeast–southwest path. In Williamsville, it meets IL 123 near its eastern terminus. It crosses two local roads, providing access to Elkhart and Broadwell before heading north into Lincoln. In Lincoln, I-55 meets the southern terminus of the second I-55 Bus. It then heads due north to intersect IL 10 and the northern terminus of IL 121. north, it meets the southern terminus of I-155. At this interchange, it heads due east to meet the northern terminus of I-55 Bus. before resuming its northeasterly–southwesterly course through northern Illinois. I-55 meets an interchange with a local road leading to Atlanta, US 136 in McLean, and another local road near Shirley before entering the Bloomington–Normal area.