SIOUX FALLS — Federal, state, and local leaders celebrated the completion of the Interstate 29 and 41st Street Diverging Diamond Interchange in Sioux Falls on Tuesday.

The interchange is now a fully operational DDI, with all lanes of traffic open. This project was developed through the coordinated efforts of the South Dakota Department of Transportation, 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. Data shows that 41st Street is the most heavily traveled street in Sioux Falls and throughout South Dakota.

The 41st Street DDI is the second interchange of its kind in South Dakota. In addition to the completed DDI on LaCrosse Street on Interstate 90 in Rapid City, four more are planned or under construction, including three in the Sioux Falls area. The other DDI project locations are: Interstate 229 and Benson Road (Sioux Falls), 85th Street and I-29 (Sioux Falls/Tea/Lincoln County), I-90 and state Highway 11 (Brandon), and I-90 and Pennington County Highway 1416 (Box Elder).

The 41st DDI project has been more than 10 years in the making and includes more than $35.5 million in roadway improvements. Project elements include on and off-ramp improvements, traffic signals, and lighting to support the new DDI, along with pedestrian and bicycle access improvements.

Guests who participated in the media presentation/ribbon-cutting event included:

• U.S. Rep. Dusty Johnson
• Sioux Falls Mayor Paul TenHaken and City of Sioux Falls Public Works Director Mark Cotter
• SDDOT Secretary of Transportation Joel Jundt
• U.S. Sen. John Thune staffer Benjamin Ready
• U.S. Sen. Mike Rounds staffer Keith Moore
• Sioux Falls city elected officials, state officials, state legislators, members of the Transportation Commission, and 41st Street project planning and operations/contractor team members

Diverging diamond interchanges have been shown to increase capacity and safety, reduce congestion, and minimize the cost of new infrastructure. Additional advantages include:

• Improved safety by reducing the number vehicles conflict points (14 compared to 26 for a conventional diamond interchange like the original I-29/41st Street interchange)
• Increased capacity by eliminating the left turn signal and allowing traffic to flow more efficiently through the interchange
• Reduced delays and congestion
• Advanced ability to meet the needs of all motorists, pedestrians and bicyclists
• Reduced construction costs due to smaller bridges

The 41st Street DDI will help enhance safety and address future travel needs and growth. These issues were included as part of the 2010 South Dakota Decennial Interstate Corridor Study and the 2012 I-29 exit 77-41st Street Crossroad Corridor Study.

For additional project details including drone photos, infographics, project statistics, and video animation demonstrating how to navigate the DDI, visit the project website at https://www.41stddi.com.

For additional information about the ribbon-cutting event, contact Julie Stevenson, SDDOT strategic communications coordinator, at 605-773-2898 or via email at Julie.Stevenson@state.sd.us or BryAnn Becker Knecht, HDR strategic communications manager, at 605-782-8172 or via email at BryAnn.BeckerKnecht@hdrinc.com.