I-39/90 Expansion Project

Illinois state line to Madison, Dane and Rock counties

Project Overview

About the project | Project purpose

The Wisconsin Department of Transportation (WisDOT) is overseeing a major reconstruction and expansion project in south-central Wisconsin. The I-39/90 Expansion Project extends approximately 45 miles along Interstate 39/90 from the Illinois state line to the US 12/18 interchange near Madison.

  • Built in the early 1960s, all of the 11 interchanges along the corridor had outdated design features that contributed to safety concerns.
  • This section of Interstate was experiencing significant traffic delays, especially during peak travel times, resulting in poor traffic flow and increased safety problems.
  • To address safety and congestion concerns, WisDOT is:
    • Reconstructing and expanding I-39/90 from four to six lanes;
    • Reconfiguring 11 interchanges; and
    • Expanding the Interstate to eight lanes (four lanes in each direction) through the Janesville area, from WIS 11/Avalon Road north to the WIS 26/Milton Avenue interchange, to accommodate projected traffic increases.

The I-39/90 Expansion Project began in 2015 and the mainline project is on schedule to be completed in 2021. Visit the Schedule section to learn more about upcoming construction work.

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Thank you for your patience as we “improve a gateway to Wisconsin.”