This is an excerpt from a contract being let July 19, showing the I-35 flyover in red and grading work in tan.
Grading in the southwest and northeast corners of the northeast mixmaster in Des Moines, and the new I-35 flyover bridge, are among the construction projects in the July 2022 Iowa DOT letting.
This is “Stage 3A” of the plan, which advances the new eastbound I-80 to northbound I-35 flyover bridge, westbound I-80 to northbound I-35 exit ramp, and eastbound I-80 to southbound I-235 exit ramp. The flyover itself is 2650 feet long — half a mile plus 10 feet.
There was a public meeting about this stage of the project nearly five years ago (PDF here) (Des Moines Register story here). The real start, though, might be considered to be the NE 54th Avenue bridge replacement just to the north of the mixmaster in 2016. At that time, transportation engineer specialist David Evans told trade publication Construction Equipment Guide that the bridge “is probably the longest span bridge not over water in Iowa.” It appears to me that the flyover bridge or one of the other two in the final build-out of the plan could replace it.
I believe there are five left exits remaining in the state of Iowa. This mixmaster project and the I-29/I-480 project that started last year will eliminate two of them.