West Des Moines, IA – Construction kicked off Monday night on the Southwest Mixmaster, a critical interchange that links Interstates 80, 35 and 235 on the west side of the metro area. The $146 million project, funded by the Iowa Department of Transportation, is slated to take about three years and will modernize a junction that has served drivers for more than six decades.
Phase one: overnight lane closures and asphalt work
Drivers on the southbound lanes of I‑80/35 will encounter temporary closures as crews begin the first phase of work. Overnight crews are applying new asphalt to reinforce the roadway and prepare it for the larger structural changes to come. “This is just the tip of the iceberg. So there will be a lot more changes coming over the next three to four years,” said Kasi Province, the Iowa DOT resident construction engineer overseeing the renovation.
New flyover bridge to replace outdated cloverleaf
The centerpiece of the project is a new flyover bridge, similar in design to the East Mixmaster bridge in Des Moines and the Highway 30 bridge in Ames. The flyover will route southbound traffic from I‑80/35 directly onto eastbound I‑235 toward downtown, eliminating the aging cloverleaf interchange that currently forces drivers into a short‑distance “zipper merge” where entering traffic must quickly blend with exiting vehicles.
Province explained, “It’ll limit the congestion, and it will make a lot more traffic efficiency and safety for the folks. So they don’t have to do that zipper merge anymore.” The new design is expected to smooth traffic flow as interstate usage continues to grow in the region.
Future work: piers, diverging diamond and lane widening
The DOT plans to begin constructing the large concrete piers that will support the flyover bridge next spring, with the bridge itself targeted for completion by 2030. In addition, lane widening on I‑80/35 just north of the Mixmaster is scheduled for later this year. Crews have already placed new steel beams for a wider bridge over Hickman Road, and a new diverging diamond intersection beneath the interstate is slated to begin construction next year.
Province asked motorists to stay patient and practice safety while the work proceeds: “Please, just be safe through those areas. And have patience with us as we construct this.” The project reflects a broader state effort to upgrade aging infrastructure, improve travel times, and enhance safety for families and commuters throughout central Iowa.
What this means for local families
For West Des Moines residents, the renovation promises smoother commutes, reduced travel delays, and a safer driving environment—benefits that align with the community’s focus on strong families and reliable neighborhoods. While temporary inconveniences are expected during construction, the long‑term payoff includes fewer traffic snarls and a modern interchange that can accommodate future growth.
The Southwest Mixmaster project underscores the Iowa DOT’s commitment to investing in critical transportation assets that support local economies, keep families moving, and uphold the constitutional right of citizens to travel safely and efficiently.
Original reporting: KCCI Des Moines — read the source article.
