Interstate 90 - Exit 406 (Brandon)

Project Summary:

This project includes the reconstruction of exit 406 (Brandon) with added lighting, signals, and mainline Interstate work. This project also includes three structure replacements.

The interchange will be reconstructed as a diverging diamond configuration.
Westbound Interstate 90 lanes (along with the railroad structure on I90) will be reconstructed in 2024 and the eastbound lanes (and railroad structure in 2025). The interchange itself and new structure over I90 will be reconstructed between 2024 and 2025.
S.D. Highway 11 traffic will be maintained across Interstate 90 during construction.
The westbound on-ramp and eastbound off-ramp are expected to be open to traffic for the majority of the project. Closures for the westbound off-ramp and eastbound on-ramp are planned for 2025.
Work will extend on S.D. Highway 11 down to Redwood Boulevard. That work includes adding a shared use path on the west side, approach and side street work, a retaining wall on the east side north of Ash St, and other items.

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Project Timeline:

Spring 2024 - Overall Completion Date: June 2026

Minor clean-up work to be completed in 2026

Project Updates:

March 31, 2025 - Press Release:

On Monday, April 7, 2025, a two-way traffic configuration will be placed on westbound Interstate 90 at Brandon (exit 406) as part of the Diverging Diamond Interchange (DDI) construction project. This two-way traffic configuration will be in place through the summer months as the second phase of construction is completed on this project.

The traffic diversion on S.D. Highway 11 over the Exit Bridge at I-90 will remain as one lane of traffic north and one lane of traffic south from Ash Street North. This configuration will be in place until the second half of the structure is complete. Access to businesses between exit 406 and Ash Street North will remain as only right-turn in and right-turn out.

The second phase of reconstruction includes completing the remaining on and off-ramps, the eastbound lanes of I-90, the Exit Bridge, and the replacement of the eastbound I-90 bridge over the BNSF railroad.

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March 18, 2025:

On Monday March 24, 2025, lane closures will be placed on westbound Interstate 90 at Brandon (exit 406) as part of the Diverging Diamond Interchange (DDI) reconstruction project.

The traffic diversion on S.D. Highway 11 over the Exit Bridge at I-90 will remain as one lane of traffic north and one lane of traffic south from Ash Street North. This configuration will be in place until the second half of the structure is complete. Access to businesses between exit 406 and Ash Street North will remain as only right-turn in and right-turn out.

The second phase of reconstruction includes completing the remaining on and off-ramps, the eastbound lanes of I-90, the Exit Bridge, and the replacement of the eastbound I-90 bridge over the BNSF railroad. Weather dependent, all phase two construction is anticipated to begin in early April.

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April 25, 2024:

March 26, 2024 - Dakota News Now:

Watch the full story here