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:
May 20, 2026:
Anticipated work from May 15, 2026, to June 15, 2026: The contractor will continue construction of two twin box culverts and installation of new pipe culverts. Loose gravel and grooved pavement will be present throughout the project until asphalt paving is complete.
Asphalt milling will continue along the 13-mile segment between the east and west entrances of Custer State Park, with paving operations to follow. Asphalt paving will start Monday, June 1, 2026, and is tentatively scheduled for completion by Independence Day. Flaggers, a pilot car, and temporary traffic signals will be in place at active work locations.
Completed work from April 15, 2026, to May 14, 2026: Guardrail was removed and asphalt milling began on U.S. Highway 16A. Motorists should be aware of grooved pavement surfaces. Work continued on two twin box culverts using temporary traffic signals. Asphalt paving was placed over new pipe culvert replacement areas.
The Custer State Park Wildlife Loop Road realignment and box culvert within the previous two-mile closure both received the first lift of asphalt. The project completion date is Oct. 30, 2026.