WYDOT’s I-90 Montana State Line Project – Year one completed

SHERIDAN, WY – Motorists traveling between the Montana state line and Ranchester 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 I-90 in late March of this year focusing on repairing five slope failures along a six-mile 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 over 180,000 cubic yards of failed soil and replaced that with over 170,000 cubic yards of scoria at these locations. 

In addition to the slope repair work completed, WYDOT milled and overlayed six miles of the westbound lane and were able to complete paving of just over two miles 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 four miles 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.

District 4, Sheridan Resident Engineer, Jake Whisonant, 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.”

Work is anticipated to start back up in March of 2026, weather permitting. 

 

 

 

 

 

 

*Photo: An aerial drone photo showing a portion of the I-90 Montana State line project where a bridge is being replaced by a box culvert and three slope failure repairs are shown.