I-80’s 1st Avenue exit in Coralville, scheduled for replacement in 2023, will be Johnson County’s first diverging diamond. That will be a year after I-380 at Tower Terrace Road becomes the first such exit in eastern Iowa.
The interesting thing about this plan (link to lots of renderings here) is incorporation of a trail crossing. The trail, on the east side of the interchange, will have underpasses at three places:
- Under a new connection between the Iowa River Landing area and 1st Avenue, approximately where the eastbound ramps meet 1st today. This will be a new intersection between the ramps (closer to I-80) and the present stoplight at 9th Street. The future street connection has a paving stub west of Von Maur/north of the UIHC clinic parking ramp already.
- Under the eastbound onramp to I-80, after which the trail takes a huge bend eastward for a pedestrian bridge and comes back.
- Under all four lanes of 1st Avenue at the westbound ramps, which means the tunnel is even longer than it would be to simply go under four lanes. The tunnel goes from the southeast corner of the westbound ramp junction to the northwest corner near the Hampton Inn.
The exit will serve the arena whose naming rights deal hasn’t been disclosed because of Coralville’s assertion that actually a nonprofit that the city created made the deal, not the city, and therefore it’s not public record.