1st Avenue & I-80 Interchange

Diverging Diamond Interchange
The Iowa Department of Transportation plans to reconstruct the interchange at I-80 exit 242 and 1st Avenue with a diverging diamond interchange (DDI).

The existing interchange at I-80 exit 242 is the original configuration constructed in the 1960s when I-80 was built through Iowa. The new diverging diamond interchange will provide safety improvements and is designed to handle projected traffic volumes.

I-80 1st Ave Diverging Diamond IDOT


  • The project is anticipated to start in fall 2022. 
  • The roadway and bridge work is expected to be complete after two construction seasons.
  • Final trail, landscaping, erosion control, and other related work will occur in the third year.

Traffic Impact
The project will utilize staged construction, including temporary pavement. There will be limited brief closures with no planned large disruption of traffic on 1st Avenue or I-80.


  • Grade-separated pedestrian trail, underpasses, and a trail bridge over I-80
  • Parallel acceleration and deceleration lanes on I-80
  • Accommodates the potential future widening of I-80
  • Two independent bridge structures to replace the existing bridges over I-80 in addition to the pedestrian bridge
  • An intersection at 11th Street/Iowa River Landing Place
  • Retaining walls, storm sewers, ditching/culverts, traffic signals, and pedestrian underpasses

The projects is funded in part by a U.S. Department of Transportation BUILD grant, with the remaining costs programmed in the Iowa DOT's five year plan.

Learn More
Iowa Department of Transportation
Iowa DOT project website

Watch Video: Navigating the Diverging Diamond Interchange