Public Invited to 41st Street DDI Educational Event at Empire Mall in Sioux Falls.

Public Invited to 41st Street DDI Educational Event at Empire Mall in Sioux Falls.

For Immediate Release:  Friday, May 10, 2024

Contact:  Kirk Henderson, Project Engineer, 605-367-5680

SIOUX FALLS, S.D. – The public is invited to an educational open house to learn about the Diverging Diamond Interchange (DDI) that is being built at the intersection of 41st Street and Interstate 29 in Sioux Falls. Construction began on the DDI in 2022. The DDI configuration will be in place at the end of May. Additional landscaping and concrete work on the islands will be completed this summer.

The open house will be held from 4-7 p.m. on Wednesday, May 22, 2024, in the former Verizon store at The Empire Mall, located at 5000 W. Empire Pl. Individuals can enter through the door on the left-side of the food court canopy outside or directly left of the food court entrance inside. Information about how to navigate the DDI and a walkable demonstration mat will be available. The project team will be available to answer questions. This will be the second operational DDI in the state of South Dakota. Construction on others are underway throughout the state.

The diverging diamond was chosen because of its safety features, along with the greater capacity and efficiency that it provides for the traveling public. It will reduce the conflict of left-hand turn movements and meet the needs of all road users to accommodate large trucks, pedestrians, and bicyclists. In total, the project includes more than $44 million in infrastructure improvements. Project elements includeon- and off-ramp improvements, new traffic signals, and lighting to support the new DDI, along with pedestrian and bicycle improvements. The project demonstrates a strong collaborative partnership among a broad range of stakeholders. The project was developed through the coordinated efforts of the South Dakota Department of Transportation (SDDOT), the City of Sioux Falls, and the South Dakota Division Office of the Federal Highway Administration.  

This is a priority corridor for the city and state as I-29 and 41st Street are vital routes for commuters and local traffic, and 41st Street is the most heavily traveled street in Sioux Falls and the state of South Dakota. Diverging Diamond Interchanges (DDIs) have been shown to increase capacity and safety, reduce congestion, and minimize the cost of new infrastructure. Advantages include:

  • Improved safety by reducing the number of ways vehicles can collide (14 compared to 26 for a conventional diamond interchange);
  • Increased capacity by eliminating the left turn signal and allowing traffic to flow more efficiently through the interchange;
  • Reduced delays and congestion;
  • Meeting the needs of all users (motorists, large trucks, pedestrians, and bicyclists); and,
  • Reduced construction costs due to smaller bridges.

For additional details, visit the project website at For updates on major traffic changes, subscribe to a free text-in service. To subscribe, simply text “41stDDI” to 605-566-4041. Subscribers can unsubscribe at any time. For commuter route information, please call the project hotline number at 605-884-7189.

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