One of Iowa’s most traveled interchanges — the point that Highway 218, Interstate 80 and Interstate 380 all meet — is nearing a five-year, $300 million overhaul.
But before major construction on the Johnson County interchange begins in 2019, state and local officials are planning several road improvements to ease the inevitable traffic problems caused by the massive interchange project.
All told, a widening project in Coralville, road updates near Tiffin and the construction of a new, roughly a $15 million interchange at I-380 in North Liberty are planned to be near completion before major construction on the 50-year-old cloverleaf interchange starts.
“They’re all driven by that I-80/I-380 interchange,” said Cathy Cutler, transportation planner with the Iowa Department of Transportation’s District 6 office in Cedar Rapids.
For more than a year, state and North Liberty officials have been crafting plans for a Forevergreen Road/I-380 interchange, which would provide a crucial detour during the later I-80/I-380 cloverleaf project.
Cutler said the state will take on the cost of constructing a $13.1 million diamond interchange where I-380 and Forevergreen Road meet.
Widening and adding turn lanes to Forevergreen Road will help the avenue better handle the added traffic entering and exiting the interstate. That portion of the project is expected to cost another $6 million, with the city and state still working on a cost sharing agreement, said North Liberty spokesman Nick Bergus.
The state will pay upfront costs, with the city paying back a portion.
Cutler said the project likely will be bid out this July, with preliminary work possible this fall.
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Bergus said the addition of a Forevergreen Road interchange will greatly benefit the growing community, which currently has only one interchange with I-380, at Penn Street. The addition of a second will give the city more flexibility in the eventual upgrading to the Penn Street interchange.
“We’ve done really about as much as we can to improve Penn Street, which has a lot of traffic. ... Without a second interchange, we’ve really been unable to take any look at widening that,” Bergus said. “It’s pretty critical to us, it will help us grow.”
The bulk of the project is expected to be completed in 2019.
In nearby Tiffin, plans are coming together to update Park Road, which runs parallel to I-380 between Forevergreen Road and Highway 6.
Tiffin City Administrator Doug Boldt said the Forevergreen Road intersection will bring “a significant amount of additional traffic” to the local road.
And there is significant development — commercial, residential and mixed use — eyed for Park Road, so planning is underway to convert it from two lanes of gravel to four lanes of pavement.
The current plan, which hasn’t reached the Tiffin City Council for approval, is to pave Park Road from Forevergreen Road down about halfway. A temporary hard surface could be installed for the remainder of the road until it reaches Highway 6, Boldt said.
One of Coralville’s main roads is expected to take on extra traffic once major construction begins on the nearby I-80/I-380 interchange.
Ellen Habel, assistant city administrator, said a Coral Ridge Avenue widening effort was not originally tied to the interchange project, but city officials soon decided to fast-track the plan.
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“We wanted to get this project finished before the 80/380 project started,” Habel said. “I think people are very eager for this next phase to be complete.”
The project is scheduled to be bid in January 2018, but that could get moved forward to this December, she said.
The $7.1 million project — with about $1.7 million of that coming from the state — will widen Coral Ridge Avenue — also known as Highway 965 — from two lanes to four between Holiday and Forevergreen roads.
Turn lanes, a median and updated traffic signals will be added.
The Iowa DOT’s Cutler said the aforementioned projects will be critical in handling shifting traffic flows — for both emergency vehicle routes and standard construction detours — caused by the five-year overhaul of the I-80/I-380 interchange.
Work on I-80/I-380 is scheduled to begin in 2019 with major traffic impacts in 2020 and 2021, Cutler said.
While lanes of traffic on I-80, I-380 and Highway 218 will remain open, Cutler said some of the existing loop ramps will close at times — with some detours in place for several months or more.
“It’s going to have traffic impacts,” she said. “There will be, I would say, entire construction seasons that traffic could be detoured.”
Cutler said detours still are being finalized.
When complete, the interchange’s cloverleaf-style ramps, which have been host to rollovers and incidents over the years, will be replaced by a sweeping, modern-style design called a turbine intersection.
“Safety really is the driving factor behind this,” Cutler said.
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