Construction Starts on $164 Million Iowa Flyover

A new bridge project in West Des Moines aims to replace an aging cloverleaf ramp to improve daily traffic flow.

Updated on Oct. 20, 2026 in Construction

Isometric editorial illustration of a steel bridge girder section being lifted by a crane over a highway interchange. — Construction crews have started work on a $164 million flyover bridge in West Des Moines to improve traffic flow on I-35/80. AI Illustration. Upload story photo >

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Crews have officially begun construction on a $164 million flyover bridge at the Southwest Mixmaster in Iowa. The project marks the first major design change at the location in more than 60 years and seeks to replace a cloverleaf ramp that has reached its design capacity.

Why it matters

The current interchange is considered a dangerous location, and the new bridge is expected to provide more reliable commute times for the 15,000 cars that use the ramp daily. The project addresses long-standing infrastructure limitations as the ramp capacity has been surpassed by modern traffic demands.

The project represents a $164 million investment in local infrastructure to replace a 60-year-old design. More than 15,000 vehicles currently traverse the existing cloverleaf ramp on a daily basis.

The players

Southwest Mixmaster

This is a major highway interchange in the Des Moines metro area that serves as a critical junction for regional traffic.

The details

Workers have deployed two cranes at the site to begin initial earth movement for the structure, which will carry southbound traffic from I-35/80 to eastbound I-235. The new bridge serves to bypass existing lanes, aiming to alleviate congestion at a site identified as a hazardous intersection in the metro area.

Construction on the flyover bridge began in October 2026.
The project is expected to be completed by 2029.

Market Landscape

This project marks a significant departure from 1960s era highway design standards by replacing an outdated cloverleaf ramp with a modern flyover structure. It positions local infrastructure to handle modern traffic volumes that have long exceeded the capacity of older regional highway designs.

Drivers using the Southwest Mixmaster should prepare for ongoing slowdowns, detours, and recurring lane changes throughout the multi-year construction process. Residents can anticipate a safer, more reliable commute once the bridge opens to traffic in 2029.

The takeaway

Large-scale infrastructure projects require significant patience as commuters adapt to long-term traffic pattern shifts. Planning your route in advance during the multi-year build can help minimize daily travel delays.