U.S. Highway 16A - From two miles east of Custer to Jct. S.D. Highway 36
Project Summary:
The project consists of the replacement of various pipe culverts on U.S. Highway 16A that have exceeded their useful life. Additional work on the project includes removing and replacing existing asphalt surfacing, repairing in-slope erosion adjacent to the highway, and improving the intersection of U.S. Highway 16A and Wildlife Loop Road.
The project also consists of the replacement of a concrete arch culvert that has exceeded its useful life.
Project Updates:
June 26, 2026:
Anticipated Work: June 27, 2026 – July 15, 2026:
The contractor will continue guardrail and pavement marking installation, along with project cleanup activities. Flaggers, pilot cars and temporary traffic signals will be in place at active work locations. The project's final completion date is Oct. 30, 2026. However, all major construction activities are anticipated to be completed by mid-July 2026. No work will be performed from Friday, July 3, 2026, through Sunday, July 5, 2026. Permanent seeding operations will be completed after Aug. 1, 2026.
May 15, 2026 – June 26, 2026: Completed Work:
Construction of the two twin box culverts was completed, including backfilling operations. All 13 miles of asphalt paving throughout the project area were completed. Installation of guardrail and pavement markings began.
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May 29, 2026 - Press Release:
Beginning Monday, June 1, 2026, asphalt paving will begin on the U.S. Highway 16A mainline in Custer State Park. Pilot cars and flaggers will be used. Motorists should expect delays. The 13 miles of mainline asphalt overlay paving will run from the Custer State Park east entrance to the west entrance. Paving is tentatively scheduled for completion on Wednesday, July 1, 2026.
Crews will not be working on the project over the Fourth of July holiday weekend. Following the holiday weekend, crews will apply a flush and sand seal to the same 13 mile stretch. This operation is expected to be complete by Saturday, July 11, 2026.
After asphalt paving operations are finished, new guardrail will be installed. It will take approximately three weeks to complete.
Current work consists of multiple pipe culvert replacements and backfilling two box culverts. These operations use temporary traffic signals and flaggers.