Wisconsin Department of Transportation

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US 12 Corridor - Alternatives

Note - WisDOT has stopped all work on the study of a future US 12 Bypass through the town of Koshkonong south of Fort Atkinson. The final disposition of the study will be determined at a future date by the Transportation Projects Commission. (May 3, 2012)

WisDOT initiated this corridor study that investigated a wide variety of alternatives that might address identified problems.

The Environmental Impact Statement (EIS) involves the analysis of several alternatives to solve traffic and safety problems along the existing route.

Preferred alternative

After considering the agency and public comments and considering the potential impacts and benefits, WisDOT decided on a multi-step approach to address the current and future needs of US 12 in the study area.

Selection of a preferred alternative

After carefully considering agency and public input, WisDOT adopted the following three-step approach to address the area’s US 12 safety and traffic issues:

  1. Officially map the preferred southern bypass route under Wis. Stat. Sec. 84.295. The preferred route is a refined Alternative 7a alignment that minimizes impacts and cost, adheres to design requirements, and meets project purpose and need.
  2. Construct interim improvements to the existing roadway focusing on operations and safety and maximizing the existing roadway’s service life.
  3. Construct Preferred Alternative 7a bypass route when safety and congestion conditions determine the improvement is a statewide priority and funding is available.

This approach recognizes that a southern bypass of Fort Atkinson will be needed in the foreseeable future and the location of the right of way should be identified and preserved to the extent possible. This will be accomplished through the official mapping process.


WisDOT’s three-step approach also acknowledges that existing 2-lane US 12 can be modestly improved such that it will meet local and regional travel needs for many more years. These near-term improvements will address safety, pavement and intersection deficiencies identified over the course of the corridor study.

To help WisDOT select the best possible southern bypass route, additional studies were conducted and Alternatives 7 and 7a were more closely examined and compared.

The layout of the proposed interchange near the Fort Atkinson Business Park was refined to maximize operations and safety. The alignment of the southern bypass routes was adjusted to avoid and minimize some of the potential impacts that were identified in the Draft EIS (DEIS). This process culminated in the selection of Alternative 7a as the preferred alternative.

This more southerly of the two bypass routes has a number of advantages:

  • Fewer wetland and woodland impacts
  • Fewer residential relocations
  • The design is safer and access management easier
  • It is expected to be less likely to stimulate unplanned development and its associated secondary environmental impacts
    • This is partly because Alternative 7a’s eastern interchange would be too distant from the municipal services needed for significant development.

The analysis and supportive evidence for selection of this alternative is contained in the technical memorandum on the dismissal of alternative 7.


This alternative will be further reviewed and documented in the Final Environmental Impact Statement (FEIS).

South bypass

WisDOT moved forward with a multi-step solution that included additional study of bypass Alternatives 7 and 7a and eliminates Alternative 1, Alternative 2b, and Alternative 3 from further consideration.

The Department’s proposal includes implementing short-term improvements similar to Alternative 1a and officially mapping a southern bypass similar to either Alternative 7 or 7a.

The mapped bypass would be constructed in the future, when safety and congestion indicate the need and funding is authorized by the State Legislature.

Alternatives studied in the Draft Environmental Impact Statement (DEIS)

A DEIS was published in December 2005. The DEIS outlined the purpose and need for improvements, several alternative courses of action and their potential environmental effects. The DEIS was circulated for public and agency review and comments were gathered.

The following map shows the alternatives Wisconsin Department of Transportation (WisDOT) investigated and documented in the DEIS.

  • Alternatives studied in DEIS
    • Alternative 1 - No action
    • Alternative 1a - Transportation Systems Management (TSM) improvements
    • Alternative 2b - One-way pair system on existing US 12 through downtown Fort Atkinson
    • Alternative 3 - Rock County N from WIS 26 to Whitewater bypass
    • Alternative 7 - South bypass
    • Alternative 7a - South bypass - wetland avoidance

A Value Planning study team reviewed all DEIS alternatives and comments, and concluded a southern bypass route would best address the stated purpose and needs. This team also recommended another version of a southern bypass alignment, named Concept J, be considered.

More detailed study of Concept J, completed in early 2008, concluded that this alternative would create more impacts, conflict with improved WIS 26 and cost more than either DEIS bypass option. Concept J has been eliminated from further consideration.

The analysis and supportive evidence for elimination of this alternative from further study is in keeping with or greater than the level of analysis and evidence that served as the basis for elimination of other alternatives considered and dismissed in the DEIS.


Before further consideration of the alternatives, WisDOT reevaluated the original traffic analysis, which was conducted earlier in the study in 2001. Traffic projections were revised using newer counts and an updated traffic model.

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WisDOT Southwest Region Office-Madison, swr.dtsd@dot.wi.gov
Last modified: June 18, 2013

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