Vault: Interchanges decade ago transform
traffic landscape of Treasure Valley

The interstate system in Idaho carries about 26% of the traffic for the entire state, with I-84 between Boise and Nampa having the highest daily volumes. The daily traffic volume has grown by approximately 39% since 2009. Three key Treasure Valley interchanges that were under construction a decade ago accommodated this rapid growth.

In preparation to widen the freeway from two lanes in each direction to four in each direction, the interchanges had to be reconstructed with the center support piers moved to the edges to create more room underneath.

Orchard Interchange
The $15.1 million project began in March 2009, and the old bridge was torn down in late October of that year. The project was completed in April 2010. The reconstructed interchange has longer, wider ramps; an expanded Orchard Street bridge; and reconfigured local roads around the interchange.
 
Vista Interchange
The $17.8 million reconstructed Vista Interchange opened in summer 2010. The interchange was Idaho’s first Single Point Urban Interchange (SPUI) — since then, the Ten Mile, Meridian and Broadway interchanges have been rebuilt as SPUIs.
 
Ten Mile Interchange
Construction on the new $33.8 million SPUI interchange at Ten Mile began in July 2009 and was complete by summer 2011. Over that winter, crews built two undercrossings north and south of the interchange, and prepared to widen I-84.

AVG. GROWTH

I-84 @ Orchard Interchange
I-84 (traffic traveling under the overpass at that location): +41%
Ramps (traffic on the two on-ramps and two off-ramps): +123%
At Orchard (traffic traveling over the interchange bridge deck): +23%

I-84 @ Vista Interchange
I-84: +43%
Ramps: +118%
At Vista: +14%

I-84 @ Ten Mile (since 2012)
I-84: +30%
Ramps: +25%
At Ten Mile: +17%

Published 02-14-20