I-535 Blatnik Bridge

Duluth, Minn., and Superior, Wis.

Frequently Asked Questions

Why are you replacing the bridge? The Blatnik Bridge is critical to the Port of Duluth-Superior. Built in 1961, it is in poor condition, has weight restrictions and traffic safety issues and is nearing the end of its service life. Without replacement, the current Blatnik Bridge is predicted to close by 2030. Constructing a new bridge will address aging infrastructure, improve safety and better accommodate oversize/overweight freight. Slated to begin construction in fall 2026, the new bridge was planned to follow the Twin Ports Interchange project in Duluth to avoid having multiple major traffic impacts at the same time. While the two states share in costs, process and decision making, MnDOT leads projects relating to the Blatnik Bridge project, and WisDOT leads projects relating to the Bong Bridge.

What is the cost, and how are MnDOT and WisDOT paying for it? The total project cost estimate for replacing the bridge is $1.8 billion, including inflation. In early 2024, MnDOT and WisDOT received $1.06 billion in federal funding in bipartisan IIJA funds from the Multimodal Project Discretionary Grant under the MEGA and INFRA program categories. The two agencies will split the remaining costs and have earmarked $400 million each for the project.

What is the timeline for new construction? Timeline is preliminary design from now until 2026, final design is 2026-27 and phased construction is fall of 2026-31, with complete bridge closure for approximately four years beginning in early 2027. This timeline could change once a contractor is hired in 2026.

What is the projected service life of the new bridge? Once completed, the new bridge’s expected service life is 100 years.

Why do we need two bridges? Two bridges between Duluth and Superior are important for reducing traffic backups, accommodating freight movements and aiding in emergency response. Having two bridges also minimizes disruptions to traffic in the event one bridge is closed due to an emergency or needed maintenance. More information on why two bridges. (PDF)

Why is it being built on the same alignment? MnDOT and WisDOT evaluated more than 25 alternatives and narrowed the list to five for deeper review. We are moving forward with building on the existing alignment with a shared-use path and a new interchange in Superior. Following the existing alignment will cost less, take less time to construct, minimize environmental impacts and help reduce construction delays/hazards for the travelling public. More information on the alignment. (PDF)

What about a tunnel? Tunnels were considered during the evaluation process. They did not move forward for further evaluation due to depth for the shipping channel and the entrance and exit grades would be too steep. Tunnels of this length would also exclude oversize loads and vehicles carrying hazardous materials. Due to air quality concerns, a single tunnel would not allow for bicycles and pedestrians.

Will there be a multi-use trail? Yes. The plan for the new bridge includes a 12-foot-wide multi-use path along the bridge.

How many workers are anticipated on the project? While the number of workers is unknown at this time, about 1.5-1.75 million labor hours is estimated to complete the project.

Why are you changing the Wisconsin approach? Traffic volumes have grown significantly since the existing bridge and interchange were constructed more than 60 years ago, which has led to increased crashes, congestion, poor operations and redirection of traffic. The new interchange will eliminate the need for the traffic signal on Hwy 53 at the approach to the bridge and reduce the amount of traffic currently using local streets to avoid the congestion that the existing structure has created. Having an interstate (I-535) end on a city street is very unusual. Changes to the Wisconsin side also will encourage slower speeds for traffic entering the city and provide a direct connection from Hwy 53 to the bridge.

What are/were public input opportunities? MnDOT and WisDOT have hosted multiple public meetings since project planning began in 2020. The public was also invited to contribute feedback throughout the Environmental Assessment process, which included studying bridge alignment alternatives. Every in-person public meeting included a recording posted online for those who were unable to attend in person. There will be many more opportunities to attend public meetings in the future.

Why does the bridge have to be closed during a portion of construction? During the environmental process where MnDOT and WisDOT studied the various alternatives, it was determined that constructing the bridge on the same alignment is most beneficial. This will minimize right-of-way impacts and costs, minimize disturbance of contaminated materials and allow for a shorter construction timeline. It also reduces the risk of constructing and demolishing bridges next to each other while traffic is present.

What does design-build delivery method mean? Because MnDOT is the lead agency on this project, there are three different delivery methods MnDOT uses for construction projects: Design-Bid-Build, Design-Build and Construction Manager/General Contractor. The design-bid process was chosen for the Blatnik Bridge project, which means MnDOT and WisDOT define the standards and general specifications expected for the bridge project and then hire a contractor to design and construct the bridge to satisfy those requirements. This process was chosen for the Blatnik project for efficient coordination between the design team and the construction team, a lower cost and more innovative design and construction. More information on design-build.

What will the new bridge look like? What is the design? This currently is unknown. The new bridge will be either a tied-arch bridge (similar to the Bong Bridge) or a cable-stay bridge (similar to the Martin Olav Sabo Bridge in Minneapolis). A visual quality committee has been formed to give guidance on colors, textures, railing, lighting, landscaping, pier caps, interpretive signage and other features of the bridge. More details will be known when a contractor has been hired through the design-build process.

Will any businesses or homes be displaced because of construction? The project is displacing four businesses in Wisconsin and partially displacing one other business. WisDOT real estate staff have or are negotiating with all property owners.

Are any roadway improvements planned before the bridge is closed to traffic? Knowing adjustments to traffic are going to need to be made to keep traffic flowing during construction, MnDOT and WisDOT studied multiple routes in Duluth and Superior and have identified proposed changes, including resurfacing segments of roadway, installing temporary traffic signals and adjusting turn lanes. These could be improved once the design-build contractor is selected. More information on traffic. (PDF)

Where will traffic be routed if a crash or weather close the Bong Bridge? Project officials are coordinating with emergency responders in Minnesota and Wisconsin to minimize such impacts and to develop a plan in advance of the Blatnik closure. In the unlikely event a closure of the Bong Bridge would be necessary, the closest two alternative crossings are southwest of the Bong Bridge – the Oliver Bridge, which carries Minnesota Hwy 39 and Wisconsin Hwy 105 over the St. Louis River, and an unnamed bridge that carries Minnesota Hwy 48 and Wisconsin Hwy 77 over the St. Croix River between Hinckley, Minn., and Danbury, Wis.

Will any dredging be occurring as part of the project? Dredging of the St. Louis River isn’t anticipated for the removal and replacement of the Blatnik Bridge. However, if dredging is required, Minnesota and Wisconsin will coordinate with all necessary agencies.

Will construction impact boat and ship traffic? The Port of Duluth-Superior is the largest on the Great Lakes, and industries in both states rely heavily on boat and ship access. Construction will be staged to allow for boat and ship traffic to continue during bridge replacement.

What is the history of the Blatnik Bridge? The High Bridge was constructed from 1958-61, opening to traffic in 1961. It replaced a swinging toll bridge around the same location that carried vehicle and rail traffic. It was renamed the John A. Blatnik Bridge in 1971. It was widened and strengthened in 1992-93 and repaired in 2013-14 and again in 2016. It was built to support loads totaling 154,000 pounds, but over the years, that weight restriction has been reduced to 80,000 pounds. Historic photos.

Will the new bridge still be called the Blatnik Bridge? When the bridge first opened to traffic in December 1961, it was known as the High Bridge. The bridge was named in honor on U.S. Rep. John A. Blatnik, who championed the project, on Sept. 24, 1971. Blatnik died a little more than 30 years after the structure was opened. Because a new bridge is being constructed, the name could be changed, but this would require an act of Congress. John A. Blatnik was born in Chisholm and worked as a chemistry teacher there after college. From 1940-44, he served in the Minnesota State Senate, and in 1946, he was elected to Congress representing Minnesota’s 8th District in the northeastern part of the state. Re-elected 13 times, he was active in transportation, serving as chairman of the Public Works Committee (now known as the Transportation and Infrastructure Committee) and shepherded the Federal Water Pollution Control Act, or the Clean Water Act, to passage. When the new bridge is built, Congress will name it, not the two states.