BOISE, ID — Modjeski and Masters announces its selection by the Idaho Transportation Department (ITD) as the prime consultant for a new bridge project to help improve traffic over the North Fork of the Payette River in Valley County, Idaho. The team will also help determine the future of the existing Rainbow Bridge, which currently sees thousands of vehicles daily. This project marks the company’s first project for ITD.

As prime consultant, the Modjeski and Masters team will support ITD with the design of the new bridge to be built on a new alignment adjacent to the existing Rainbow Bridge, working closely with project partners Kimley-Horn, RBCI, NV5, Russo Structures, and Anderson Environmental.

The project will be challenging given its location in a narrow canyon with a significant skew, with the teams’ most critical considerations including contractor access, minimizing hillside cuts, constructability, and scheduling aspects given seasonal traffic patterns. The work will also include highway improvements on both sides of the bridge, as well as the construction of retaining walls along the steep canyon slopes in order to prevent rockslides and erosion.

In addition to the design and construction of the new bridge, the project includes environmental studies and research on the surrounding wetlands, endangered species, and cultural resources; technical studies including geotechnical and hydraulics work; community involvement such as public meetings and stakeholder groups; and determining the future of the existing Rainbow Bridge.

The contract is scheduled to last approximately three years. The preliminary design portion of the project is underway, with construction plans currently scheduled for 2028-2029.