Project Overview

Sundt is completing the widening of a 3.9-mile stretch of I-15 to three lanes in each direction as part of a multi-year program to widen a 51-mile-long corridor between Pocatello and Idaho Falls. The team’s scope of work includes improving interchange ramps, replacing bridges and machine underpasses and increasing vertical clearance for overpasses.

The two major structures integrated into the highway design are a 2.5-mile road bridge and a machine pass, an underpass specifically designed to allow farm machinery and equipment to pass through. The project includes 15,000 feet of concrete median barrier separating the northbound and southbound lanes. This will be the first time that concrete median barrier has been slip formed on an ITD project. The median walls vary in height from 6.5 feet to 12 feet tall and use over 12,000 cubic yards of concrete to construct. At its completion, the project team will install nearly 325,000 tons of aggregate base to the roadway.

This project ties into the ITD I-15 System Interchange, starting with the widening where the interchange left off and continuing to expand to the north. The lane widening began amid ongoing work to the north by another contractor as well as at the I-15 System Interchange, requiring careful coordination among the three sites.

In collaboration with ITD, Sundt was able to rephase the project and expedite the schedule, and they will complete near the end of 2026.