Wisconsin Department of Transportation

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US 12/18 Freeway Conversion Study
Madison-Cottage Grove, Dane County

View SW, US 12/18 Freeway Conversion Study - Dane County in a larger map.
Map key - Thick orange line is the project overview/location. Blue tear drop with dot in center is the project limit.

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Project location

US 12/18, I-39/90 (Madison) to County N (Cottage Grove), in Dane County.

Project overview

  • Extends approximately 3.5 miles.
  • Identify the preferred alternative for converting US 12/18 from a 4-lane expressway to a 4-lane freeway.
    • An expressway is a high-speed divided highway with partial access control. At-grade intersections, median crossovers, and some driveways are allowed.
    • A freeway is also a high-speed divided highway, but direct access is allowed only at interchanges. Overpasses and frontage roads are used to provide connections for local traffic and to direct vehicles to the interchanges.
  • Possible alternatives include:
    • Addition of interchanges
    • Grade-separated overpasses
    • Frontage roads to connect local roadways
  • Alternatives will be evaluated to determine the level of safety improvement, costs, right of way needs, land use, and environmental and local impacts.
  • An Environmental Assessment (EA) to be completed as part of this study.
  • Evaluate the impacts of converting US 12/18 to a freeway and to identify and preserve the recommended alternative.


Study with no construction activity at this time.

Questions about the content of this page, contact:
WisDOT Southwest Region Office-Madison, swr.dtsd@dot.wi.gov
Last modified: July 31, 2014

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