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US-95: Culdesac Canyon Passing Lane

Construction in the canyon over the next seven years will add an 11-mile passing lane from Winchester to Culdesac for southbound drivers to provide safer opportunities to pass.

Phase 2 ongoing
Corridor cost
More than $50 million
Traffic impacts
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Corridor plans

The Idaho Transportation Department is in the process of adding a passing lane for southbound drivers on Winchester Hill through the canyon. Work started in 2016 and will take several years to complete.


Construction costs are expected to be more than $50 million. Once completed, the passing lane will be 11 miles long. Culverts and other structures will be upgraded to be more fish-friendly as well.

Resurfacing in 2021

Three sections of US-95 totaling eight miles in the canyon from milepost 273 to Culdesac will be resurfaced in 2021 to address deteriorating pavement between the already-planned phases to add a passing lane.

Construction photos from 2019 to 2020

Photos show progress on construction over the last two years. The aerial photo was provided by Barnes Inc.

Photo of construction on US-95 in Culdesac Canyon in 2019 Photo of construction on US-95 in Culdesac Canyon in 2019 Photo of construction on US-95 in Culdesac Canyon in 2019 Aerial photo provided by Barnes Inc. of blasting and drilling efforts on US-95 Culdesac Canyon construction in 2020 Photo of the unpaved future passing lane in Culdesac Canyon
Passing lane added between mileposts 289 - 290.5
Asset 5
Spring 2019 - Fall 2020
Construction to add a passing lane between mileposts 279 - 282
Asset 5
Passing lane to be added between mileposts 283 - 286
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Passing lane to be added between mileposts 296 - 289
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Passing lane to be added between mileposts 282 - 283
Asset 5

Downloads & Resources

Asset 5

Season 1 ends

About 1.5 miles of new passing lane was completed but not paved.

Season 1 summary
Asset 5
April 2019

Daytime blasting

Although most complete closures of US-95 will be scheduled at night, during the second week of April, traffic will be stopped in both directions to allow the construction of an equipment access trail above the rock slope. Rock and other debris will be pushed off the slope into a catchment area for cleanup. Drivers should expect delays of at least 15 minutes; if rock falls onto the road, delays could become longer as crews remove it.

Asset 5
March 2019

Signage and guardrail work begins

Expect reduced speeds now that contractors are on scene to replace signage and guardrail.

Construction overview


The final season of Phase 2 is underway, with the first closure for blasting scheduled March 12. Read more.

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US-95 Culdesac Canyon: contact us

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