Interstate 270 Corridor Upgrades in St. Louis

Frequently Asked Questions

What is being done in this area? 
MoDOT is rehabbing or replacing bridges that were not included in the I-270 North Design-Build project. That includes the I-270 bridges over Route 367 (Rehab or Replacement), over Bellefontaine Road (Replacement Only), over the BNSF railroad (Rehab Only) and the Lilac Bridge over I-270. The project also includes the rehab or replacement of the Dunn Road bridge over BNSF railroad, as well as the expansion of I-270 from two continuous lanes to three from Lilac to Route H. Modifications to the ramps at Lilac will also be made. Finally, the project includes culvert rehabilitation near Route AC and the resurfacing of I-270 from Route 367 to Chain of Rocks Bridge.

When will work begin?
The projects are currently scheduled to begin construction in 2026.

How long will the work take?
Construction will proceed through the 2028 construction season.

Will all the work be done at the same time?
No, it is anticipated the projects will be split into two projects with one beginning in 2026 and the other in 2028. An exact timeline of when the projects will be done will be available closer to construction beginning.

What is the cost of the project? 
To complete all of the projects, the current STIP has allocated approximately $50 million. The breakdown of costs is as follows:

• $32 million is for the I-270 bridges
• $13 million is for the replacement of the Lilac interchange and the addition of a third lane on I-270
• $3 million is for resurfacing

Why wasn’t this work done with all the other construction in the area? 
The work was not all done at one time due to funding constraints from both the total amount of construction dollars needed and the sources of the funding. The Chain of Rocks Bridge project was funded jointly by MoDOT and IDOT and was constructed out of sequence with the improvement of the I-270 North Design-Build project.