I-57 / IL-16 Interchange Reconstruction at Mattoon

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IDOT is proposing to reconstruct the I-57/IL 16 interchange located east of Mattoon.  At this location, I-57 is a rural four-lane divided interstate and IL 16 is a rural four-lane divided highway.  This section of IL 16 provides access between the cities of Mattoon and Charleston.  The interchange is currently a cloverleaf configuration that has four inner loop ramps and four outer ramps to provide access between I-57 and IL 16.

The I-57/IL 16 interchange is being reconstructed to eliminate over-height vehicle impacts to the I-57 bridges over IL 16, to address the structural deficiencies of these bridges and to address the geometric deficiencies of the cloverleaf interchange while minimizing the effects on capacity. 

As part of the reconstruction, the I-57 bridges over IL 16 will be replaced and raised to provide a minimum vertical clearance of 16’-6” from the IL 16 pavement to the bottom of the bridge beams.  Also, the cloverleaf interchange configuration will be removed and replaced with a new raindrop diamond interchange.  The ramps of the new interchange will extend through the I-57 bridges over the Lincoln Prairie Grass Trail.  To accommodate the new ramps, the existing bridges over the trail will be removed and replaced with a 16’ wide by 14’ tall box culvert.  This project will address the stated issues for the interchange while maintaining a smooth, continuous, safe, and efficient flow for large volumes of traffic.

Update 2/1/2023:  IDOT continues to coordinate with the City of Mattoon.  Design plans are continuing to be developed and the land acquisition process has started.  Construction of this project is tentatively scheduled to begin in late 2023 or early 2024.  Construction should last approximately 3 years.

Note: IDOT projects typically have three distinct phases. Phase I (or the project Study) consists of developing the project scope, environmental studies and preliminary design of a project. Phase II (Design) consists of refining the design to develop contract plans and land acquisition. Phase III (Construction) consists of the actual construction of the project.