I-39/90 Expansion Project

Illinois state line to Madison, Dane and Rock counties

WIS 81 interchange

WisDOT will construct a Diverging Diamond Interchange (DDI) at the I-39/90 and WIS 81 interchange in Beloit. The new DDI is anticipated to open in fall 2021 (subject to change).

Upon completion of this project in 2021, I-43 traffic with a destination in Beloit must exit at County X/Hart Road (Exit 2) and follow WIS 81 into Beloit. View the I-39/90 and I-43/WIS 81 interchange navigation mapPDF

Why a DDI at the I-39/90 and WIS 81 interchange?

WIS 81 has a significant amount of traffic making left turns onto the Interstate. During a typical day, it’s projected an average of 7,000 vehicles will merge onto I-39/90 northbound from WIS 81. Due to the high volume of left turns onto the Interstate, a standard diamond interchange design was not as efficient at reducing traffic congestion.



The following documents are in Adobe PDF PDF format.
(Note: Some files are large and may take longer to download depending on individual connection speeds. Users may need to zoom in to see details.)

How to Navigate the WIS 81 DDI: