IDAHO CITY, Idaho, Sept. 10, 2026 — Rehabilitation work on the Mores Creek Bridge along State Highway 21 is set to begin Sept. 11, as the Idaho Transportation Department moves forward with a project designed to preserve the 73-year-old bridge and extend its service life.
The approximately nine-month project will keep the bridge open throughout construction. Crews will complete the work on one half of the structure at a time, with traffic reduced to a single lane through the work zone.
Temporary traffic signals or flaggers will control vehicles at both ends of the bridge. Motorists should anticipate delays of up to 15 minutes during active construction periods. Wide loads traveling to Lowman or Idaho City will need to use State Highway 55 during the project.
The rehabilitation program will address several maintenance needs affecting the Mores Creek Bridge. Crews will clean and repaint steel components to help protect them from corrosion, replace bridge deck seals and repair deteriorating concrete.
The project will also address erosion around the bridge, helping protect the structure and surrounding infrastructure from further deterioration.
The bridge was originally constructed in 1953 and has received multiple maintenance and preservation treatments over its service life. Rather than pursuing full replacement, the current work is intended to extend the bridge's useful life by approximately 26 years.
The project reflects an infrastructure preservation strategy focused on maintaining existing transportation assets before more extensive replacement becomes necessary.
Keeping the bridge operational while crews work in stages will allow traffic to continue using SH-21, although travelers should plan for reduced speeds, lane restrictions and temporary delays.
ITD is advising motorists to use caution through the work zone and check current road conditions before traveling. The rehabilitation is expected to remain active for roughly nine months as crews complete structural maintenance and preservation work.
Rehabilitation projects such as the Mores Creek Bridge work can extend the useful life of aging transportation infrastructure while postponing the need for full reconstruction. For Idaho's highway network, targeted repairs to structural steel, concrete, deck seals and erosion areas can help maintain bridge reliability and preserve a critical route for local and regional traffic.
Source: Idaho Transportation Department.
