Three major bridge reconstruction projects in Chicago are set to cause significant traffic disruptions and extended commute times for residents and commuters. These closures, affecting key routes into and out of the Loop, are expected to last for years, impacting both vehicle and public transit users.
Key Takeaways
- Three major bridges – Chicago Avenue, Lake Street, and Cortland Street – are closing for long-term reconstruction.
- Closures will significantly affect traffic flow and public transit commutes in and out of the Loop.
- The Cortland Street Bridge project began in September 2025 and will last 18 to 24 months.
- The Chicago Avenue Bridge closure started in late September 2025, with work expected until December 2026.
- The Lake Street Bridge will close in October 2025, with reconstruction planned until January 2028.
Cortland Street Bridge Project Underway
The reconstruction of the Cortland Street Bridge over the north branch of the Chicago River commenced on Monday, September 22, 2025. This project is projected to span between 18 and 24 months. During this period, vehicle traffic in both directions is prohibited between Mendell Street and Kingsbury Street. Pedestrian access will be limited, with only one sidewalk remaining open until winter 2025.
The city's plan for the Cortland Street Bridge includes several key upgrades. Workers will replace the bridge deck, the steel floor system, and the counterweights. New concrete-filled grating, railings, and lighting will also be installed. Additionally, the bridge houses are scheduled for renovation.
Cortland Street Bridge Facts
- Start Date: Monday, September 22, 2025
- Estimated Duration: 18 to 24 months
- Closure Area: Vehicle traffic between Mendell Street and Kingsbury Street
- Pedestrian Access: One sidewalk open until winter 2025
Detours are in place to manage the flow of traffic around the Cortland Street Bridge closure. Eastbound vehicle traffic is being redirected south on Ashland Avenue, then east on North Avenue, and finally north on Clybourn Avenue to rejoin Cortland Street. For westbound traffic, the detour directs drivers south on Clybourn Avenue, west on North Avenue, and north on Ashland Avenue before returning to Cortland Street.
Understanding Bascule Bridges
Many Chicago bridges, including the Lake Street Bridge, are bascule bridges. These movable bridges have a counterbalanced span that pivots upward to allow marine traffic to pass. Their complex mechanical systems and structural components require specialized maintenance and reconstruction, leading to extended closure periods.
Chicago Avenue Bridge Reconstruction Begins
The Chicago Avenue Bridge, located over the Chicago River, is now fully closed to all traffic between Larabee and Peoria streets. This closure began on Monday, September 29, 2025. It forms part of a larger, ongoing project to reconstruct both the bridge and the adjacent Halsted Street viaduct.
City officials have outlined the scope of this significant undertaking. The existing temporary bridge structure will be removed. It will be replaced with a permanent tied-arch bridge. This project also includes the creation of a new riverwalk connection beneath the bridge. The entire Chicago-Halsted viaduct will undergo a full replacement.
"These projects represent critical investments in our city's infrastructure," a city spokesperson stated. "While we understand the inconvenience, these long-term closures are necessary to ensure the safety and longevity of our vital bridge network."
Extensive Upgrades for Chicago Avenue
Beyond the bridge itself, the project encompasses several other improvements. Traffic signals in the area will be modernized, and a new traffic signal will be installed at the intersection of Chicago Avenue and Jefferson Street. Street lighting will be replaced across the project zone. Additionally, new dedicated bike lanes are planned for Halsted Street, and CTA bus lanes will be created on Chicago Avenue to improve public transit efficiency.
The work on the Chicago Avenue Bridge is expected to continue until December 2026. Eastbound traffic will follow a detour via Ashland Avenue, Division Street, and LaSalle Street to return to Chicago Avenue. Westbound traffic will be redirected via Orleans Street, Division Street, and Ashland Avenue to reconnect with Chicago Avenue.
Chicago Avenue Bridge Project Details
- Start Date: Monday, September 29, 2025
- Estimated Completion: December 2026
- Key Components: New tied-arch bridge, riverwalk connection, viaduct replacement, traffic signal upgrades, bike and bus lanes.
Lake Street Bridge Closure Scheduled
The Lake Street Bridge, spanning the south branch of the Chicago River, is scheduled for a complete closure to both vehicle and pedestrian traffic starting Monday, October 6, 2025. The closure will affect the segment between Canal Street and Wacker Drive. This reconstruction project is anticipated to be the longest of the three, with work expected to last until January 2028.
Despite the extensive closure for vehicles and pedestrians, CTA Green and Pink Line train service across the bridge will largely continue without interruption. However, two planned shutdowns for train service are scheduled for Fall 2026 and Spring 2027 to accommodate specific phases of the construction.
Lake Street Detour Routes
Drivers traveling eastbound on Lake Street will be detoured from Desplaines Street to Washington Street, then to Franklin Street, before returning to Lake Street. Westbound traffic will be rerouted from Wacker Drive to Madison Street, then to Jefferson Street, and finally back to Lake Street. Pedestrians will be directed to use a detour via Canal Street to Wacker Drive on Randolph Street, according to city officials.
Lake Street Bridge Closure Summary
- Start Date: Monday, October 6, 2025
- Estimated Completion: January 2028
- Impact: Full closure for vehicles and pedestrians; CTA train service mostly uninterrupted, with two planned shutdowns.
Impact on Chicago Commuters and Traffic
These three simultaneous bridge closures are expected to have a significant impact on traffic flow throughout downtown Chicago and surrounding areas. The Chicago Avenue and Lake Street bridges are particularly important arteries for drivers and CTA users commuting from the city's West and Northwest Sides into the Loop.
Commuters should prepare for longer travel times and consider alternative routes or modes of transportation. Public transit users, while largely unaffected by the Lake Street train service, may experience delays due to increased bus traffic on detour routes.
The city encourages residents and visitors to plan their journeys in advance, stay informed about the latest detour information, and allow extra time for travel. Updates on these projects will be provided regularly by the Department of Transportation.
