Keller Associates, Inc.

US 95, Electrical Substation to Smith Creek

Idaho Transportation Department

OVERVIEW

Keller Associates provided complete roadway design services for the reconstruction of US 95, north of Moscow, ID, furthering the Idaho Transportation Department’s goal of upgrading Idaho’s primary continuous north-south highway. This 6.5 mile segment runs through difficult rolling and mountainous terrain along numerous creeks and waterways in Latah and Benewah Counties and within the Coeur d’Alene Tribe Reservation.

CHALLENGE

The existing roadway had sharp curves and poor sight distance in many areas. There were limited passing opportunities and slow truck traffic because of the steep grades over the Marsh Hill Summit. There are sensitive creeks and drainages alongside much of the highway.

SOLUTION

Keller Associates optimized the new alignment to avoid wetlands and creeks where possible and looked to balance earthwork quantities within the project corridor. The earthwork design addressed over 1.3 million cubic yards of excavation, with cuts and fills as high as 150 feet and 100 feet, respectively. Climbing lanes were incorporated over the Marsh Hill Summit to ease slow traffic concerns, and turn lanes were built at the new county roadway intersections. Other interesting project components included the protection of adjacent creeks, relocation of a historic cabin, enhancement of 6 acres of wetlands, and extensive right-of-way. The project construction cost was about $12 million.



			Electrical Substation

			Downtown Revitalization

			Roadway Rehabilitation


	• Rural Highway Design • Drainage • Erosion Control • Utility Relocation • Right-of-Way Plans • Signing & Pavement Marking • Construction Traffic Control Plans • Environmental Services • Wetland Mitigation Site Design • Historic Cabin Relocation • Construction Services to ITD