Eastbound I-80 on-ramp reopens as 1st Avenue interchange nears completion

Work on a diverging diamond interchange in the heart of the Iowa River Landing in Coralville is entering its final stages.

The eastbound 1st Avenue on-ramp to Interstate 80 reopened on Wednesday, a milestone in the 1st Avenue interchange project, which has added a bridge, altered traffic patterns, and created new, resurfaced highway exit and entrance ramps.

The eastbound on-ramp closed on June 3 and was expected to remain impassable through mid-August. All four exit and entrance ramps are open after being resurfaced and restructured to match the current traffic pattern.

The previously closed right lane after 9th Street, near Trader Joe's, reopened as an entry point to Interstate 80.

Crews will put the finishing touches on the eastbound and westbound off-ramps in the coming weeks, with work set to wrap by the end of August. According to the city's release, the project is approximately 80% done and on target to be completed by the end of the year.

Drivers can access the interstate on-ramps without using a traffic signal, according to the city's release.

More: Parking rates at ramps, meters will increase in Iowa City beginning July 1. What to know

Work is nearly complete on area's first diverging diamond

When the $42 million project began in March 2023, traffic navigated a two-lane bridge near the highly trafficked, fast-developing Iowa River Landing.

In the 16 months since, a second bridge was built and the traffic pattern was drastically rearranged for the Iowa City metro's first "diverging diamond" interchange, which aims to improve safety and traffic flow.

In diverging diamonds, drivers are directed to the opposite side of the road near on- and off-ramps. The Iowa Department of Transportation said the design "eliminates conflicts where traffic crosses," reducing the likelihood of collisions while providing a more efficient means of navigation.

This is because, for example, drivers exiting the highway and turning left need only pull into the closest lane rather than crossing traffic.

The Coralville interchange at 1st Avenue (between 9th Street and Holiday Road) is one of the busiest in the Iowa City metro area, leading to the heart of Coralville, the Iowa River Landing and Xtream Arena to the south, and residential areas to the north.

A separate pedestrian and cycling bridge and tunnel were also built.

One-lane traffic will continue on the two bridges in each direction until the project is complete. The finished diverging diamond will make use of two-lane traffic in each direction, matching 1st Avenue to the north and south.

More: Diverging diamond traffic pattern debuts at 1st Avenue interchange. Here's how it'll work:

Ryan Hansen covers local government and crime for the Press-Citizen. He can be reached at [email protected] or on X, formerly known as Twitter, @ryanhansen01.

This article originally appeared on Iowa City Press-Citizen: Coralville's diverging diamond nearly complete as eastbound ramp opens