CSAH 21 Downtown Prior Lake Reconstruction, Scott County, Minnesota

CSAH 21 Downtown Prior Lake Reconstruction

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Scott County, Minnesota


“This is the first meeting I have been to where I felt heard; not only heard, but listened to—I had my questions answered directly.”

– Participant of the Corridor Visioning Group

The TH 13/CSAH 21 intersection and CSAH 21 corridor in downtown Prior Lake lacked capacity to move traffic safely and efficiently. The corridor had been studied multiple times over the last two decades without identifying a solution supported by all stakeholders. While a recommended plan was adopted by the board of commissioners in 2005, significant concerns were raised and major conflicts existed between access and mobility, roadway classification, and community needs.

Recognizing this history, Bolton & Menk led an innovative and comprehensive public engagement effort using various outreach formats. Our work included a visioning study, the goals of which were to engage the public, build trust between governing agencies and the public, and develop a solution that could be supported by stakeholders. The visioning study was used to level the playing field, start over, and identify important community values.

As part of the larger vision, we focused our efforts on creating a road to downtown Prior Lake, not through it. The intersection reconstruction project evaluated potential improvements to the 13/21 intersection and those in close proximity, in particular CH 21/Main Avenue and CR 21/Arcadia Avenue. It also considered traffic impacts on surrounding streets, including to pedestrian safety and accessibility. Because Minnesota Valley Transit Authority (MVTA) and the community had a long-term desire to expand transit service to downtown Prior Lake, Bolton & Menk also considered how to reconfigure existing transit stops to reduce conflicts between vehicles and pedestrians attempting to cross CR 21 and the transit users and providers.

Our flexible approach was key to project success. After several months of identifying and evaluating concepts, conducting public engagement, and coordinating with applicable agencies, a single vision was adopted by MnDOT, Scott County, and the City of Prior Lake. The ultimate configuration was two ¾ intersections, which improved mobility while preserving access. It also included two roundabouts flanking downtown Prior Lake and Main Avenue, which improved traffic movement and increased safety by slowing drivers through the heavily traveled area of pedestrians and bicyclists. It also provided improved aesthetics to the downtown area by creating a sense of a destination when traveling between the roundabouts. Bolton & Menk also converted the existing transit stops into bus pull-offs. We relocated them slightly to fit within the slower traffic area and integrated them into the downtown streetscape. They are now within a short walking distance to public parking areas, and the enhanced pedestrian crossing across CH 21 at Main Avenue will further help facilitate travel of all types in this community.





  • Great Lakes District of the Institute of Transportation Engineers – 2021 Transportation Achievement Award – Traffic Engineering
  • Institute of Transportation Engineers – 2021 Transportation Achievement Award – Traffic Engineering
  • American Council of Engineering Companies of Minnesota – 2020 Honor Award
  • City Engineers Association of Minnesota – 2020 Project of the Year Honorable Mention
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