Collaboration delivers I-84 project benefits
to drivers years ahead of schedule

The I-84 project encompassed nearly 13 miles, from the Hansen Interchange (junction with Idaho Highway 50) to Ridgeway Road (junction with Idaho Highway 25).

This project consolidated seven projects into three, reducing five years worth of work into two years, and in the process delivered safety and mobility benefits to area drivers years ahead of schedule. The outcome was a smoother, safer roadway for the traveling public.

This effort to consolidate $46.4 million involved the collaborative work of several parties:

- Within a year, the consultant delivered four eastbound projects. Three westbound projects were under one contract the following year.
- Crews completed both eastbound (2017) and westbound (2018) lanes within two construction seasons.

The project also exemplified a “bigger project with lower cost” approach because it allowed for buying in bulk. It saved ITD from being subject to inflation that would occur over time with a longer project.

Consolidation of the projects also vastly improved work zone safety.  The design eliminated the need for multiple crossovers and fewer changes in traffic patterns, which pose safety concerns for motorists.

The project originally called for full reconstruction, but through materials investigations, it was found that the material present was of a higher quality than the material that would have been imported for use.  This discovery allowed the project team to reduce the project scope from a full reconstruction to a base regrading with minor sections of reconstruction, which fixed geometric deficiencies. Then plantmix pavement was placed.

Not only did this save millions of dollars in project costs, but the end result was actually a stronger road.

Another important factor involving budget was the contractor's propsed elimination of the the cement-treated base, replaced instead with plant mix. 

The six planned projects finished early, and the seventh project was also added to complete work on this section of the corridor.

Published 04-05-19