Interstate 64/70 and U.S. Route 61 Interchange Improvements

What is the current problem?

Motorists experience significant delays and traffic backups navigating this interchange during peak traffic periods. Specifically, westbound I-70 and westbound I-64 experience high levels of traffic congestion during the afternoon rush hour approaching and traveling through the interchange and extending as far west as Wentzville Parkway on I-70. In addition, the current interchange design is outdated as I-70 traffic increases and the western area of St. Charles County has grown exponentially in the last 20 years.

Why is this project needed?

The I-70/I-64 interchange serves a large amount of traffic volume daily, with additional growth anticipated in the future.  Currently, approximately 75,000 vehicles use I-64 south of the interchange daily, while U.S. 61 carries over 60,000 per day.  As both a major east-west interstate of national importance, and a commuter route connecting western St. Charles County to the rest of the St. Louis region, I-70 serves 85,000-90,000 vehicles per day.  A large percentage of existing and future traffic includes tractor trailers, lending to the importance the interchange with respect to freight movement.

During the morning rush hour, traffic is significantly higher along eastbound I-70 and southbound U.S. Route 61. During the evening rush hour, traffic is higher traveling westbound on I-70 and I-64.

The most severe congestion occurs during afternoon drive time at the interchange. Traffic on I-64 westbound is consistently congested between Route 364/Route N and Route K, while congestion on I-70 extends between 2 and 4 miles east of the interchange with the longest backups in the vicinity of Lake St. Louis Blvd.

The afternoon bottleneck causes stop and go traffic on westbound I-70 and I-64, leading to safety issues at the interchange.

From 2015 to 2019, 837 crashes occurred, averaging 167.4 crashes per year. The most common type of crash was rear-ending collisions.

The interchange also experiences several sections where weaving occurs, including westbound I-70 between I-64/U.S. Route 61 and Route Z, I-70 westbound to northbound U.S. 61, and southbound U.S. Route 61 transitions to eastbound I-64.