Missouri Route 370 Bridge Rehabilitation in St. Charles and St. Louis Counties

What is the purpose of this project?

The Route 370 Discovery Bridges over the Missouri River will undergo a major bridge rehabilitation project starting in winter 2026. This project is expected to be completed in fall 2027. 

Major river crossings like the Route 370 Discovery Bridge are very important to the efficient flow of traffic between St. Louis and St. Charles counties. Each bridge carries approximately 25,000 vehicles per day.

How will the work be completed? 

Starting in winter 2026, weather permitting, crews will construct median crossovers to split traffic on the eastbound and westbound bridges to complete the bridge rehabilitation. 

What are the traffic impacts?

During the project, MoDOT will maintain two through lanes in each direction of Route 370, with two of the westbound lanes temporarily shifted to the eastbound bridge. A  temporary barrier wall will separate both directions of traffic. 

Drivers can expect a work zone speed limit of 50 mph, narrowed and shifted lanes through the limits of the work zone.  The work zone is anticipated to lead to some backups during peak commuting times, so motorists are encouraged to avoid those times if possible.

Drivers can use the I-70 Blanchette Bridge, Route 364 Veterans Memorial Bridge or the I-64 Boone Bridge to cross between St. Louis and St. Charles counties as an alternate route. 

Will the shared use path remain open during the bridge work?

The shared used path on the Westbound Bridge will be closed during the bridge rehabilitation. Both the Katy Trail North in St. Charles County and the Missouri Greenway North Trail in St. Louis County  will remain open during the bridge rehabilitation project.