Projects

US-95 Culdesac Canyon Passing Lane

A southbound passing lane will provide safer opportunities to pass south of Lapwai.

US-95 Culdesac Canyon Passing Lane

A southbound passing lane will provide safer opportunities to pass south of Lapwai.

Overview

By adding passing opportunities and upgrading infrastructure along US-95 through Culdesac Canyon, this project will improve safety and mobility to meet current environmental and transportation standards. Planned improvements include a 11-mile southbound uphill passing lane from milepost 279 to 290 and replacing culverts to improve fish passage.

Rural highway curves through a forested canyon with roadside delineators in the foreground and mountains in the distance.

Corridor plans

This project in Culdesac Canyon will add a southbound passing lane and replace existing culverts to improve fish passage in the area. Construction began in 2016 and is being completed in phases over several years.

  • Phase 1

    Completed construction between mileposts 289 and 290 in 2016.

  • Phase 2

    Expanded US-95 by adding over two miles of passing lane and replaced nine aging metal culverts between mileposts 279 and 282 in 2020.

  • Phase 3

    Construction on the Rock Creek Culvert was substantially completed in 2022. Work will resume in summer 2026 to complete the culvert and construct approximately three miles of southbound passing lane between mileposts 283 and 286.

  • Phase 4

    This phase extends the southbound passing lane three miles between mileposts 286 and 289 and construction is anticipated to start in 2028.

  • Phase 5

    This phase will extend the southbound passing lane between mileposts 282 and 283 and construction is anticipated to start in 2030.

A map graphic shows the phased construction timeline for the U.S. Highway 95 Culdesac Canyon Project between Culdesac and Winchester. Completed sections from 2016 and 2020 are shown in green, a 2026 construction segment is highlighted in orange, and future phases scheduled for 2028 and 2030 are shown in black. The map also marks Reubens, county boundaries, railroad bridges and directions toward Lewiston and Grangeville.

FAQ

Construction in Culdesac Canyon was suspended in 2022 following an inadvertent fish take on Lapwai Creek during in-stream work activities. The Idaho Transportation Department has continued coordinating with the National Marine Fisheries Service and other federal partners to meet environmental requirements and secure updated permits needed to resume work safely and responsibly.

Since then, the dewatering strategy has been improved for in-water work to help protect fish during construction, which includes on-site coordination with the Nez Perce Tribe to relocate the fish away from active construction zones before in-water work begins.

ITD anticipates resuming work in June 2026 following the completion of the permitting process. Crews will finish the Rock Creek culvert, construct new retaining walls, and install riprap supports along the corridor.

This section of US-95 includes steep grades and limited passing opportunities, which can contribute to congestion and risky passing maneuvers. The additional lane is intended to improve traffic flow and reduce unsafe passing along the corridor.

Contact

Howard.Cooley@itd.idaho.gov

Project News