U.S. Highway 12 - S.D. Highway 1806 and S.D. Highway 63
Project Summary:
U.S. Highway 12 - From 12 Miles East of McLaughlin to West of Mobridge
Full-depth reclamation, completed in 2025, and asphalt concrete surfacing on U.S. Highway 12 is being done to eliminate the existing reflective cracking and rough joints on the existing road. Undercutting and subgrade reconstruction through the heave area on S.D. Highway 1806 is being done to eliminate the existing pavement heaving and restore a normal crown to the highway. This work, combined with the milling and asphalt concrete resurfacing of S.D. Highway 1806, S.D. Highway 1806P and S.D. Highway 63 will restore a normal crown to the highways and provide for a smooth pavement surface. Guardrail is being replaced on all routes with bridges to improve safety, and culverts are being repaired as necessary to ensure proper drainage and extend the life of the roadway.
U.S. Highway 12
In 2025, work on the highway included 3-4” of Cold Milling followed by reclaiming of 3-5” of inplace asphalt concrete and 4-5” of granular material. Once this material is reshaped and compacted, 4-5 ½” of Asphalt Concrete will be placed.
S.D. Highway 1806
Heave Area repair (south of bridge over railroad) will include removal of the top 3 feet of surfacing and subgrade material, reworking and compacting the subgrade material, placing 9” of Base Course and finally resurfacing with 4” of Asphalt Concrete.
S.D. Highway 1806 south of U.S. Highway 12, S.D. Highway 1806 north of U.S. Highway 12, S.D. Highway 1806 Spur Route to Wakpala, and S.D. Highway 63 north of McLaughlin
Resurfacing of these four routes will include 1” of Cold Milling followed by one 2” lift of asphalt concrete.
All Routes
Culvert repair will be done on all five routes and guardrail will be replaced at all bridge locations.
Project Updates:
April 17, 2026 - Anticipated Work:
Spring work started the week of April 13 with culvert replacement east of the Oak Creek Bridge and base-course reinforcement north of the Wakpala School on S.D. 1806. Work on the slide repair on Highway 1806 south of U.S. Highway 12 has also started and should be nearly complete by the end of April. Culvert repair work will continue on Highway 1806 north of Highway 12.
Anticipated Work in May 2026:
Culvert replacement and subgrade repairs on Highway 1806 north of Highway 12 should be completed in May. Slide repair on Highway 1806 south of Highway 12 should also be completed in May.
The second lift of asphalt concrete will be placed on Highway 12 west of Mobridge. Milling and asphalt-concrete resurfacing will also take place in May on the following routes: Highway 1806 south of Highway 12, Highway 1806 north of Highway 12, the Highway 1806 Spur into Wakpala, and S.D. Highway 63 north of McLaughlin.
--
On Monday, April 13, 2026, a project is scheduled to begin on U.S. Highway 12 from Mobridge west approximately 15 miles and on S.D. Highway 1806 both north and south of Highway 12. The Highway 12 project will primarily involve pipe and guardrail corner improvements on the shoulders of the highway.
On Highway 1806 north of Highway 12, work will include mainline pipe installations and short grading sections. Traffic will be reduced to one-half width in these work zones during daytime hours, with flaggers and a pilot car guiding the traveling public.
On Highway 1806 south of Highway 12, work will focus on a slide repair. Traffic will be controlled with stop signs through the work zone. At times during the daytime, flaggers and a pilot car will guide the traveling public.
Commuters should be alert through the entire work zone for workers adjacent to moving traffic, construction vehicles entering and exiting the work zones, and changing traffic patterns.
Nov. 21, 2025:
Oct. 15, 2025 – Nov. 15, 2025:
Completed Work: On U.S. Highway 12, the contractor completed final shaping and priming. Paving of the first lift of asphalt concrete was finished on Oct. 30. Permanent pavement markings were placed and completed on Nov. 5.
Anticipated Work Nov. 15, 2025 – Dec. 15, 2025: No additional work is planned for the remainder of the season. Work is expected to resume in spring 2026 and will include completion of pipe work and placement of the final lift of asphalt concrete on U.S. Highway 12; cold milling, asphalt concrete resurfacing, and pipe work on S.D. Highway 1806 (north of U.S. 12) and S.D. Highway 1806P (Wakpala Spur) and S.D. Highway 63 (north of McLaughlin); and cold milling and asphalt concrete resurfacing on S.D. Highway 1806 (south of U.S. 12).