The $435 million project reconstructs the system-to-system interchange of I-535 and US 53 with I-35 in Duluth, Minnesota.

Formerly known as the “can of worms”, the Duluth project is a massive multi-phase effort that will untangle the current system by incorporating safety improvements while replacing aging infrastructure on this northernmost point of I-35. The interchange experiences an average of 80,000 vehicles each day, of which 5,320 are classified as heavy commercial. A significant goal of the project is to improve the movement of freight and goods between the ports of Duluth, Minnesota, Superior, Wisconsin, and the upper Midwest.

Key project elements include:

  • interchange reconfiguration and geometric safety improvements
  • stormwater treatment and system improvements
  • geotechnical soil stabilization and load transfer platforms
  • utility relocations and improvements
  • creek realignments
  • local roadway upgrades.
Duluth interchange construction

Construction work on the I-35 interchange in Duluth

Interchange of I-525 and US 53 with I-35

Interchange of I-535 and US 53 being constructed in summer 2022







Alliant’s multi-year involvement began in 2016 with a preliminary engineering design effort.

Following preliminary design, MnDOT selected the Construction Manager/General Contractor (CMGC) alternative delivery method for the project. Alliant was part of a CMGC design team selected for final design of the roadway elements of the project. We completed the challenging and fast-paced design in 19 months generating a total of four separate work packages let for construction.

Alliant team members coordinated extensively with the CMGC contractor to solicit input on design features resulting in enhancements to the staging approach, location of bridge foundations, and refinement of the challenging geotechnical improvements. Alliant led the development of complex 3D models that aided design and are currently being used by the CMGC contractor for efficient construction of the project through machine control grading systems. Construction began in January 2021 and is anticipated to be completed November 2024.

From highway engineering to surveying and landscape architecture, our entire team has contributed to this project. As we watch it progress through construction, we continue to be amazed at how infrastructure projects can so positively impact a community and the traveling public.

Drone footage taken September, 2022.


Photos and videos provided by MnDOT.