Six decades after it was first constructed, the Pocatello-Chubbuck area's "Flying Y" interchange is getting a rebuild in what the Idaho Transportation Department is calling a "massive undertaking."

According to an ITD press release, "The design needs to be updated to handle greater traffic volumes and to replace aging bridges that are reaching the end of their life."

Preliminary work on the project to reconstruct the Flying Y interchange connecting Interstates 15 and 86 has begun and contractor SundtCannon has started to move equipment into the area. It is projected that construction will take three years and cost $112 million.

"When completed, approximately 900,000 cubic yards of excavation will be completed," ITD wrote in the press release. "In addition, about 225,000 tons of base material will be brought in; 111,000 tons of asphalt will be placed; and over 6,500 cubic yards of concrete will be poured. About 70,000 square feet of retaining walls will also be built throughout the project area. Finally, ITD will build eight new bridges. Four of those will use precast concrete girders and four will have steel girders. In all, nearly 5,000,000 pounds of steel will be used in the bridges. Crews will work year-round for approximately three years to complete the project."

Beginning in early August, there will be a detour for motorists traveling on I-15 northbound onto I-86 westbound. The detour will take travelers through the Northgate Interchange, then back onto I-15 South and then onto I-86 West.

Also in August, the Chubbuck Road overpass bridge will be closed and its traffic will be detoured through the Northgate Interchange. The bridge will be closed for the duration of the Flying Y project. ITD says the new Chubbuck Road design will be safer and easier to navigate.

Fixing and reconstructing aging bridges is important for Pocatello's future, according to Flying Y project co-manager Greg Roberts, because lots of "mega loads" pass through Pocatello and companies need to know that they will be able to get their products to consumers without hassle and delays.

"The aging bridges will continue to get closer and closer to the end of their design lifespan," Roberts said in the ITD press release. "They would still be functional, but weight limits would start to have to be imposed on truck traffic. That would negatively impact Pocatello's economic future."

The Fying Y project is also needed because of the Pocatello area's growth.

These days there are many houses, Highland High School, the Bannock County Event Center, The Church of Jesus Christ of Latter-day Saints temple and more in the Flying Y's vicinity that weren't there 60 years ago. Plus, the adjacent Northgate area is expected to bring in more growth.

"We can only expect traffic volume to increase and with it congestion," Roberts said. "That will cause the weave between the Pocatello Creek onramp (on I-15) and the Chubbuck exit (on I-86) to get worse. Traffic entering I-15 intending to head toward Chubbuck already has difficulty during peak times crossing all the way to the left to head west on I-86."

ITD calls the project "truly historic" and noted that it took many years and "extensive coordination" to get to this point. Throughout the process, ITD has been working with area leaders, stakeholders, law enforcement and emergency responders.

Project details are available at itdprojects.org/ projects/i-86-i-15-systeminterchange.