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project changes saved $170,000

Work at busy Lewiston intersection
improves traffic flow, reduces delays

The intersection of US-12, 21st Street, E Main Street, and G Street in Lewiston is one of the busiest in the entire region, with more than 50,000 vehicles per day using the intersection. It is also a gateway to workers and patrons of the area’s largest employers. It plays an important role in the community, so it required unique planning.

Challenges were numerous. The four roads converged to create a five-legged intersection that was home to many crashes. There were pedestrian-vehicle conflicts, and the reality of driver movements were often different than what was expected.

In the past five years, there have been 34 crashes at the intersection, including rear-end crashes, head-on crashes and sideswipes. In addition to heavy truck traffic from industrial mills east of the intersection, nearby businesses generate significant traffic. These businesses include Clearwater Paper, Idaho Forest Group, and Lewiston’s primary commercial business district along 21st Street.

District 2 reconstructed and realigned the intersections in an $8 million project. D2 also partnered with the city on $1 million of improvements to storm sewer and potable water facilities.

“We used new concrete to resist rutting caused by heavy commercial truck traffic and will save maintenance time and effort,” explained ITD north-central Project Manager Curtis Arnzen. “The pavement in this location prior to the project had heavy rutting and was a continual maintenance problem.”

Horrocks Engineers was contracted to provide construction engineering and inspection services.

Construction of the intersection was completed within budget and five weeks early. The completed project will reduce delays by approximately 30%. Without these improvements, delays at the intersection would cost the traveling public more than $25,000 per day by 2041 in time spent away from work, gas consumed while idling, etc.

Throughout construction, the project continually received positive feedback and support from the public. In an online opinion poll on the Lewiston Tribune homepage, more than 78% of responders gave the project a grade of A or B.

Two change orders were executed prior to construction to save the project $170,000 —a 60-inch storm sewer pipe was used in lieu of 72-inch storm sewer pipe for a savings of $84,400, and a mechanically stabilized earth retaining wall was used instead of two soldier-pile retaining walls, saving $86,000.