Interstate 55 Bridge Replacement at Loughborough Avenue and Weber Road in St. Louis

What is the problem?

The Loughborough Avenue bridge over Interstate 55 in the city of St. Louis needs to be replaced as part of the ongoing work of keeping the state highway system in good repair. When replaced, it will be updated to meet current standards. The bridge is 69 years old and was rehabilitated roughly 40 years ago The interchange hasn’t been updated since the interstate was constructed in 1956. 

Vehicle sizes and speeds have changed significantly since the 1950’s so a replacement would include bringing the bridge up to current standards. In addition, the city of St. Louis needs to replace the Loughborough Avenue bridge over the railroad tracks just to the west for the same reasons.  It makes sense to replace both of these bridges at the same time to minimize impacts to drivers and to get a better finished product.  MoDOT is partnering with the city to complete these bridges at the same time.

The Weber Road bridge over Interstate 55 also needs to be replaced. That bridge is also roughly 60 years old and was rehabilitated about 40 years ago.  This bridge will also be replaced and adjusted to meet current standards for the interstate, which includes minor alignment changes to the ramps themselves.

What is the proposal at Loughborough?

Any work at this area would not start until late 2027. MoDOT and the city of St. Louis will remove and replace both the bridge over the interstate and the bridge over the railroad tracks at the same time. With a full replacement, now is the time to raise the bridge to meet Federal standards, accommodate the needs of all future users, and look for any safety enhancements that can be made. 

Based on the city’s current bike and pedestrian planning, a shared use path is being considered in the plans on the south side of the bridge. Two possible safety improvements that are currently being considered are moving the northbound exit ramp off Idaho to meet Loughborough directly, and possibly using a roundabout-style interchange at the ramp terminals. 

Why is the City of St. Louis replacing the Loughborough Bridge over the railroad tracks to the west of I-55? 

The bridge, which was built in the 1950s, needs to be brought up to current standards to meet traffic and safety needs. 

What are the impacts?

Both bridges at Loughborough (the bridge over the interstate and the city’s bridge over the railroad tracks) will be closed for a period as the bridges are removed and replaced.  Although we don’t have a specific timeline, doing it this way will reduce the amount of time it takes to complete the work on the bridges and the new interchange. Trying to keep one lane open as crews work through this project is less safe for both the people traveling through the work and for the construction crew and will take more than twice as long. We will work to stagger the ramp closures to reduce the impact of the work to all Loughborough users. We are still working through details on the plans which will help determine how long each ramp will be closed. 

Will the City’s project be done at the same time as MoDOT’s project? 

Yes, the current plan is a partnership between MoDOT and the city of St. Louis to complete both projects at the same time to limit the overall impacts to businesses, residents and other roadway users in the area.

Why could a roundabout-style of interchange be a good idea for Loughborough?

Roundabouts are one of the safer types of intersections, as they reduce the chance for both head-on and side-impact crashes, which are the most likely to cause serious injuries and fatalities. Without signals, waiting times can be reduced.  In a roundabout, traffic only goes one direction, so drivers yield to traffic to their left that is in the roundabout. Pedestrians generally use a sidewalk around the roundabout, and only have to cross one lane of traffic going in one direction, which tends to be safer for them as well. In this situation, this type of interchange helps all users move efficiently and safely.  The roundabout can be built large enough for emergency vehicles to safely and efficiently make it through, as well as tractor-trailers heading to the businesses in Loughborough Commons and elsewhere. Another benefit unique to Loughborough is that a roundabout design would eliminate the angled path cars currently have to take through the signalized intersections to continue straight on Loughborough across the interstate.