Motorists traveling between the Montana state line and Ranchester, Wyo., will notice the road is a little smoother than it was a year ago.
The Wyoming Department of Transportation and its contractor, Croell Inc., began working on the westbound lane of Interstate 90 in late March 2025, focusing on repairing five slope failures along a 6-mi. stretch of shoulder.
A slope failure happens when the underlying soils, commonly clay, become overly saturated and lose their "sticky" factor and give way to gravitational pull. Most of these clays are sitting on a shale base, offering little to no resistance for the clay to adhere to. The soil becomes too heavy and follows the path of least resistance and falls away from the slope, encroaching into the shoulder of the highway and potentially into the lane of travel.
To repair these slopes, the contractor cut away the failing soils, created benches and backfilled those benches with scoria. The lightweight scoria allows moisture to drain through the slope without becoming saturated. Contractors removed more than 180,000 cu. yds. of failed soil and replaced that with more than 170,000 cu. yds. of scoria at these locations.
In addition to the slope repair work completed, WYDOT milled and overlayed 6 mi. of the westbound lane and was able to complete paving of just over 2 mi. of the eastbound lane — originally scheduled to be completed next year. Two bridges were removed and replaced with box culverts, and the Parkman Exit bridge decks were repaired.
Year two work, scheduled for 2026, will include realigning approximately 4 mi. of the eastbound lane from mile marker 3.9 to 8.0. This realignment is required to accommodate multiple slope failures that have been encroaching on the shoulder for several years. Two additional bridges will be removed and replaced with box culverts within the realignment road section.
Jake Whisonant, District 4, Sheridan resident engineer, was pleased with the amount of work Croell was able to complete this year.
"The contractor and their subs moved through year one's scope efficiently and were also able to complete some additional paving of the eastbound lane to this year, which will lighten up the remaining schedule," he said.
Work is anticipated to start back up in March of 2026, weather permitting.
