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.

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 build 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.

How to Navigate the WIS 81 DDI: