Study Overview

The project consists of the reconstruction and/or adding lanes to Interstate 55 (I-55) and Interstate 72 (I-72), including interchange improvements and additional lanes, from north of Toronto Road to north of Sherman and from just east of Old Route 36 on I-72 to just west of Veteran’s Parkway/IL Route 4 in Sangamon County. It includes reconstruction of the interchanges at Sixth Street/I-72, Stevenson Drive, South Grand Avenue, Clear Lake Avenue/I-72, and Sangamon Avenue. It also includes reconstruction of numerous structures within the project limits.

The project is located in Sangamon County on the south and east sides of Springfield. It is located in Illinois Department of Transportation District 6 in Central Illinois. The Toronto Road interchange is at Milepost 90 on I-55 and the Sherman interchange is at Milepost 105. Along I-72, the Old Route 36/Camp Butler interchange is at Milepost 104 and the Veteran’s Parkway/IL Route 4 interchange is at Milepost 93. The total length of the project is approximately 15 miles along I-55 and the joint section of I-55/72 and 3 miles along I-72. 

I-55 in the state of Illinois is a major north-south interstate highway that connects St. Louis and Chicago. The interstate was constructed in sections across Illinois in the 1960s and 1970s and replaced U.S. Route 66 in response to the need for a national highway system. The 4-lane section of I-55 around Springfield was completed in the late 1960s. The I-55 sections north and south of Springfield were widened to six-lane sections a decade later in the 1970s, therefore, creating a bottleneck around Springfield, IL.

I-72 is a major east-west interstate highway extending across Illinois from Champaign, Illinois to the Mississippi River. I-72 is a 4-lane section through Springfield. The portion of I-72 from Champaign to Springfield was completed in 1976. The portion of I-72 from its joint route with I-55 west around Springfield was designated I-72 in 1995.

The purpose of the project is to provide safer, more efficient, and more reliable traffic operations for local and through traffic on the I-55 corridor from north of Toronto Road to north of the Sherman interchange and on the I-72 corridor from Veterans Parkway/IL Route 4 to just east of the Old Route 36 (Camp Butler/Exit 104) interchange, including the joint section of I-55/72 from the Sixth Street interchange to the Clear Lake Avenue interchange.

The project is needed because the existing traffic capacity of the I-55/72 corridor is insufficient to adequately support existing and future traffic volumes and the I-55/72 corridor has outdated designs and design deficiencies, mostly at the interchanges. The insufficient traffic capacity, outdated designs, and design deficiencies contribute to traffic congestion and delays and decreased safety for motorists. Traffic volumes have steadily increased over the previous five decades and roughly tripled since the interstate was constructed in the late 1960s.