Illinois Department of Transportation US Route 20

Baxter & Woodman provided Phase II Engineering for this 2.7 mile, $11M project, which consisted of various improvements along U.S. Route 20. U.S. Route 20 is a northwest‐southeast Other Principal Arterial and Strategic Regional Arterial (SRA 511). The roadway is classified as a Class II Truck Route and is maintained by the IDOT. The improvements included:

• Three intersection improvements, including a 5-leg roundabout at U.S. Route 20 and Marengo Road (FAS 35)/Beck Road/South Union Road (FAS 34A)
• Channelization improvements and widening at U.S. Route 20/Coral Road and U.S. Route 20/West Union Road
• U.S. Route 20 roadway profile adjustment
• Removal & replacement of an existing box culvert with multiple drainage culverts along U.S. Route 20
• Resurfacing of U.S. Route 20 outside reconstruction and widening areas

All intersection improvements were designed for staged construction with two-way traffic maintained at all times on U.S. Route 20.

The existing culvert (SN 056‐0087) was an 8-foot x 4-foot reinforced box culvert and did not meet the necessary freeboard requirements. Improvements consisted of installing three separate new concrete box culverts spaced approximately 20 feet apart and raising the profile of U.S. Route 20 to accommodate the new culverts and to prevent roadway overtopping from a 50-year storm event. Aerial view of culvert improvements. Two retaining walls were needed on the east and west sides of U.S. Route 20 to support the area between the main culvert and flanking culverts. The improvements included staged construction with one‐way traffic maintained along U.S. Route 20 via temporary traffic signals.