West Des Moines Highway Project Begins Construction

Local businesses should prepare for significant traffic slowdowns and route detours through the 2029 completion date.

Updated on Oct. 20, 2026 in Construction

Isometric editorial illustration of massive concrete bridge piers and steel beams under construction in a simplified, muted landscape. — Construction has officially commenced on the $164 million Southwest Mixmaster flyover bridge in West Des Moines, targeting completion by 2029. AI Illustration. Upload story photo >

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Construction is underway on a $164 million flyover bridge at the Southwest Mixmaster in Iowa, a move designed to replace an outdated cloverleaf ramp. The project aims to improve safety and transit efficiency for the 15,000 vehicles that use the interchange daily.

Why it matters

The project addresses a critical congestion point that has reached its design capacity, marking the first major upgrade to this intersection in over six decades. By replacing the existing loop, operators can expect more reliable commute times for logistics and personnel once the infrastructure is modernized.

The $164 million project replaces a ramp currently serving 15,000 cars daily. This investment represents the first major design change at the Southwest Mixmaster in over 60 years.

The players

Southwest Mixmaster

A major regional highway interchange serving as a primary connector for interstate traffic in the Iowa metro area.

West Des Moines

A key municipal authority overseeing the local impact of regional infrastructure and commercial transit corridors.

The details

The new bridge will carry southbound traffic from I-35/80 directly over existing lanes to eastbound I-235, eliminating the current restrictive loop ramp. Crews have begun initial earth movement utilizing heavy machinery and cranes to clear space for the new structure. The design is intended to alleviate safety concerns and capacity limitations inherent in the current configuration.

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

Market Landscape

This project marks the first major departure from the mid-century design standards that have governed the Southwest Mixmaster for over 60 years. It follows a broader regional trend of upgrading outdated highway infrastructure to handle modern traffic density.

Businesses reliant on the I-35/80 to I-235 corridor should prepare for persistent slowdowns and route changes through 2029. Logistics managers should re-evaluate delivery windows and detour capacity for fleet vehicles navigating the Southwest Mixmaster during this period.

The takeaway

The project serves as a reminder to track regional infrastructure capital plans that may affect your delivery transit costs for the next several years. Monitor local transportation department updates for specific lane closure schedules to adjust your routing and logistics planning in real time.