OVERVIEW

Project Purpose

I-39/U.S. 20 was constructed in the early 1960s, with the I-39/U.S. 20 interchange (system interchange) constructed in 1980 and the I-39/U.S. 20/Harrison Avenue interchange in 1963. The existing pavement varies throughout the project corridor, with some overlays and repairs taking place on numerous sections throughout the years.

Phase I included capacity analyses, crash studies, condition assessments, and future traffic projections for the study area. Results of these studies determined the need for redesign and reconstruction of the corridor and associated interchanges, including connecting roadways, structures, and noise walls.
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The purpose of the proposed improvements to I-39 is to:
  • Improve conditions at the interchanges.
  • Reduce congestion on the roadways.
  • Improve safety and provide continuity with adjacent roadways.
Kishwaukee Bridge

Study Phases

IDOT projects typically have three distinct phases.
Mall Drive

Phase I: Project Study (Completed)

The Phase I Design and Planning Study of the I-39 corridor was completed in 2019. The study included historic analyses of the roadways, capacity studies, crash studies, safety analysis, existing conditions assessment, alignment analysis, land use, and an evaluation of environmental resources and concerns on the possible effects of reconstruction on the surrounding environment. The study concluded that reconstruction of the corridor was necessary due to safety and capacity issues, as well as current and future projected conditions.
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The reconstruction of I-39 will:
  • Improve capacity, safety, and operations on I-39 using 3 thru lanes in each direction, with northbound and southbound auxiliary lanes.
  • Improve capacity, safety, and operations on the I-39 ramps at the U.S. 20 Interchange by widening from one lane to two lanes.
  • Improve capacity, safety, and operations at the I-39 Harrison Avenue Interchange by eliminating the low-speed loop ramps and converting to a Diverging Diamond Interchange.

Phase II: Design

IDOT and the design consultant are currently preparing plans, specifications, and estimates for construction. Since Phase I was completed, revisions to the final design due to further analysis include the following:
  1. Perryville Road Realignment
    Phase I design called for the new bridge to be built adjacent to the existing bridge using a curved roadway. Phase II redesign now has the new bridge to be reconstructed at the same location as the existing bridge using straight roadway. Mulford Road will be used as a detour during construction.
  2. Mulford Road Alignment
    Phase I design called for the new bridge to be built next to the existing bridge using curved roadway. Phase II redesign now has the new bridge to be reconstructed at the same location as the existing bridge using straight roadway. Perryville Road will be used as a detour during construction.
  3. I-39 Alignment Shift
    Phase I design reduced distance from traffic to the east right-of-way with added lanes. The Phase II redesign has been revised to hold the east edge of the pavement for the alignment.
  4. New Noise Walls
    During Phase II, the consultant team conducted a noise reevaluation to reflect the updated Noise Policy. The proposed re-evaluation has identified the potential inclusion of two new noise walls, segments along I-39.
  5. Kishwaukee River Bridge
    During Phase II, replacement of the U.S. 20 bridges over Kishwaukee River was determined necessary.
  6. Cherry Valley Path
    Phase II design warrants the temporary rerouting of the Cherry Valley Path during construction.

Phase III: Construction

The proposed improvements are constructed, operated and maintained.