IA: Southwest Mixmaster Interchange Replacement Project

Safety Improvements Are in the Mix in West Des Moines 

Challenge: Built in the 1960’s when Des Moines’ population was less than half its current, the I-35/80/235 interchange, also known as the Southwest Mixmaster, is one of the most dangerous in the state. Going between highways requires sharp turns with short merge areas. The southbound I-35/80 to eastbound I-235 ramp was designed to handle 1,000 vehicles an hour but now carries 1,500 an hour, based on 2016 numbers. That number is expected to grow to 2,000 per hour by 2050. 

 Solution: With help from federal infrastructure investment, the Iowa Department of Transportation is upgrading this outdated interchange with new flyover ramps and road realignments. When finished, drivers will be able to exit, enter, and merge between highways more seamlessly and safely.  

What they’re saying: “This interchange has held up for many decades under significant traffic volume. But it’s past time for a revamp to enhance efficiency and ensure drivers’ safety. These federal dollars will help get the millions of people who pass through our capital city each year where they want to go.” – U.S. Sen. Chuck Grassley (R) (Des Moines Register, 09/23/2024)