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:

Oct. 31, 2025:

On Thursday, Nov. 6, 2025, the northbound S.D. Highway 11 to eastbound Interstate 90 exit 406 (Brandon) on-ramp will be temporarily closed for approximately four hours beginning in the afternoon. There will also be a second temporary ramp closure at the westbound I-90 exit 406 off-ramp to southbound Highway 11 for approximately four hours. Both scheduled ramp closures are weather dependent and subject to change.

Both closures are needed for crews to place permanent pavement markings. Message boards will be placed around the work zone to alert motorists of the closure.

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Oct. 27, 2025:

Sept. 15, 2025 – Oct. 15, 2025, Completed Work:
All concrete has been placed at the exit. Most permanent pavement markings have been completed from the Ash Street intersection with S.D. Highway 11 south to Redwood Boulevard. The traffic signals at Ash Street are functioning as intended. At the railroad bridge, the deck, barrier curb, and approach slabs have been poured, and most of the bridge deck falsework has been removed.

Anticipated Work Oct. 15, 2025 – Nov. 15, 2025:
Median grading and topsoil placement will continue. Remaining traffic signals are expected to become fully functional at the diverging diamond interchange, and additional permanent pavement markings will be completed along S.D. Highway 11. Gravel grading and paving of the remaining eastbound lanes are expected to be finished. Lighting installation and permanent signing will also begin or be completed.