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ITD prepares to bid $100 million overhaul of ‘Flying Y’ interchange

The Idaho Transportation Department plans to accept bids soon for an estimated $100 million overhaul of the “Flying Y” interchange that joins Interstate 15 and Interstate 86.

ITD Engineer Manager Eric Staats, said the work will be bid in early 2022, and construction is planned to commence in the late summer.

ITD also launched an unrelated study on Wednesday examining the logistics of widening I-15 one section at a time from Pocatello to Idaho Falls. Though the Flying Y project will include two lanes, Staats said the bridges will be designed to leave room for a third lane, with an eye to the future.

Some of the existing bridges have ramps with a single lane.

Construction of the new interchange is expected to take more than two years, wrapping up in early 2025, Staats said. ITD has been working on the design for the past seven years.

Engineering was done in-house, and the project encompasses roadway, ramp and bridge upgrades, as well as the addition of a pedestrian and bicycle path.

“We’re pretty excited. It’s a big project right in our backyard,” Staats said.

ITD has already budgeted for the project, so progress won’t be contingent on obtaining any grants or additional funding. Nonetheless, Staats said the state is in an “unprecedented place” regarding the availability of federal funding for infrastructure projects. The federal government recently passed a $1.2 trillion infrastructure bill, and obtaining some of that funding for work on the Flying Y would free up funds for other projects, he explained.

Staats explained the project is needed both to improve traffic flow and to update aging bridges and infrastructure. Though the bridges are still in serviceable condition, he said they were built in the 1960s, have been rehabilitated a couple of times already and are reaching the end of their expected lifespan.

Regarding traffic flow, Staats said the major problem the project will correct is the short distance motorists who enter I-15 at the Pocatello Creek Road exit have to cross lanes and merge onto the I-86 exit to the left.

“You don’t have a lot of time, and there are just more cars out there than there used to be,” Staats said.

The project will move northbound lanes of I-15 slightly to the west, toward the southbound lanes, allowing ITD to move the I-86 exit to the right-hand side. The improvements will remove the need for motorists to change lanes and jockey for position, Staats said.

“It should be much more intuitive — a much easier movement,” he said.

Eight bridges will be constructed, including a couple of new structures to realign northbound I-15, crossing over ramps, similar to the current design of the southbound lanes at the Flying Y.

Currently, Chubbuck Road passes over I-15. The project will move Chubbuck Road to ground level and route I-15 onto a bridge above it, which should be more convenient for oversized loads that are currently too large to pass under Chubbuck Road.

Chubbuck Road will be wide enough below the bridge to accommodate a sidewalks and bike lanes, enabling pedestrians and cyclists to access the Portneuf Wellness Complex.

Based on input from a public meeting on the project hosted in 2017, ITD is also partnering with the Portneuf Greenway Foundation on building a 10-foot-wide recreational pathway within ITD’s right-of-way connecting Pocatello Creek Road to the Portneuf Wellness Complex. Staats said the Portneuf Greenway plans to connect the new trail to another segment of trail from Monte Vista Road to Pocatello Creek Road as part of a larger vision to build a continuous trail from the city’s north end to its southern end.

ITD intends to create an informational video on the project and has additional information posted at http://arcg.is/fLHDK.


By JOHN O’CONNELL, Idaho State Journal