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 1950s so a replacement would include bringing the bridge up to modern 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 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 raising the bridge and minor adjustments to the ramps themselves.

What is the proposal at Loughborough?

Work in 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. Crews will raise the bridge to meet Federal standards, accommodate the needs of all future users, and improve safety. Based on the city’s current bike and pedestrian planning, a shared use path is being included in the plans on the south side of the bridge. The northbound ramp from the interstate will be moved from Idaho Avenue to connect directly to Loughborough to eliminate interstate traffic driving on city streets. This will mean, however, that Idaho Avenue will no longer connect to Loughborough, on either side of the intersection.  Idaho Avenue will become two-way between Haven and Loughborough and Blow and Loughborough. 

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 around 14 months as the bridges are removed and replaced.  Fully closing the bridges to replace them 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. Replacing the Weber bridge is estimated to take about 8 months and will include various ramp closures as well.

What kind of pedestrian accommodations will be made during work?

There are roughly 200 pedestrian trips per day using the Loughborough bridge to cross over the interstate to Loughborough Commons, and the nearest crossing is more than 3 blocks away at Koeln. The department did look at putting in a temporary pedestrian crossing; however, accessibility issues, utility lines and the roadway layout between the east and west side of the interstate made that impractical. The department is interested in hearing ideas from the community to address pedestrian crossings, which may include shuttle services or coupons for ride-hailing services or delivery services.

Are you still considering a roundabout?

No.  As MoDOT engineers worked through the design process, they determined that a roundabout would not fit into the available space well, while incorporating the other elements that the department has heard from the community are important.

Why wasn’t this work done at the same time as the I-55 bridge work?

Removing and replacing Loughborough during the interstate bridge work would have placed undue strain on the community.  Although ramps were closed (in only one direction at a time), closing the bridge across the interstate would have significantly impacted traffic crossing between the east and west sides of Loughborough, forcing traffic to take routes that were already congested by traffic detouring around various interstate ramp closures. In addition, since we had lanes closed on the interstate for the shifted traffic for the bridge work, it would have made it challenging to do the Loughborough bridge foundation work (which requires additional work on the sides and middle of the interstate) around the lane closures.  

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

Yes, the current plan is that MoDOT will partner with the city of St. Louis and oversee the contract for both bridges to limit the overall impacts to businesses, residents and other roadway users in the area.

The following general themes were shared by the public during an August 24, 2026 public meeting at the Carondelet Branch of the St. Louis Public Library and online through September 9, 2026.   A– MoDOT will take the information that was shared during the public meeting and make any final changes to the plans, before putting the contract out for bid sometime in late 2027.  Work on the project should start shortly after the project is awarded. You can view the full summary of the public meeting here: Loughborough and Weber bridges over I-55 public meeting summary.

The following concerns were shared during the public meeting:

Potential impacts to the Carondelet Connector/Greenway:

The Carondelet Connector should stay open for most of the time, except when work is going on directly overhead – such as bridge demolition, girder setting or concrete work.

Increased traffic on other arterial corridors:

There will be increased traffic on several city arterial routes due to this traffic.  Fortunately, detour routes for the Weber and the Loughborough bridge do not use the same routes, so they complement each other, even if both bridges are underway at the same time. 

Work during the evening or overnight:

Since both projects are in residential areas, work hours will, most likely, be during the day – probably about 7 a.m. to 7 p.m. depending on weather.  There will be times, especially when there is work directly over the interstate, such as demolition or girder setting, that requires a full closure of the interstate for a weekend, that residents can expect nighttime work.  There may also be nighttime work when concrete is placed for the bridge deck, depending on temperatures.

Impact to through traffic on I-55:

For the most part, the impact to through traffic on I-55 should be minor.  One lane will be closed in each direction as crews are working on the foundations for the bridge – either the inside (left)  lane when they are working on the middle of the bridge or the outside (right) lane when they are working on the portions of the foundation near Loughborough. There will be times where the interstate will be closed for a weekend to remove the old bridges, and may be times when the interstate is closed for short periods when the girders are being placed for the new bridge.

Concerns about vibrations impacting residences or businesses:

MoDOT will ask the contractor to monitor any potential vibrations during the construction process especially around the Loughborough bridge work to avoid causing significant vibrations during construction. 

Access from Weber to southbound Interstate 55:

Since there is a full interchange at Bayless, it would interfere with any access to Weber to the south, making it unsafe for people to enter or exit the interstate at either Weber or Bayless.