I-29 Corridor Study


The SDDOT has the responsibility to develop and maintain the interstate and highway system throughout the state. As part of their continuous monitoring and management the SDDOT has identified the section of I-29 from US 18 (Exit 62) through the Tea interchange (Exit 73) as a corridor in need of a major rehabilitation or replacement within the next eight years. Evaluation of potential needs in the I-29 corridor goes beyond the mainline pavement condition to include the critical cross routes that may bridge the mainline or in the future may warrant an interchange with I-29.

Corridor Map

I-29 Corridor Study Map – Click to view.

Many of the structures crossing I-29 are original to when the interstate was first constructed and are nearing the end of their useful life. These include the following bridges and/or interchange structures:

  • 281st Street bridge over I-29
  • Exit 64 Interchange (SD44) structure
  • 278th Street bridge over I-29
  • Exit 71 Interchange (273rd Street) structure

Proximity of this I-29 segment to the Sioux Falls metro area enhances the desire to look at not only the current conditions, but the longer-term travel needs as metro growth continues. The Lincoln County comprehensive plan and the future land use plan for the area that is included in the 2040 Long-Range Transportation Plan both anticipate nodes of commercial growth occurring at the cross routes with access to I-29 and expansion of communities that will influence travel within the I-29 corridor and each of the cross routes.

Tea is anticipated to continue growing east to I-29 with a combination of residential and commercial uses. Harrisburg is farther from I-29 and its growth will likely influence the SD 115 corridor more directly than I-29; however, there is the expectation that east-west travel between I-29 and Harrisburg will increase over time. Growth in these two communities, along with Worthing and Lennox to the south of the Sioux Falls metro, generates the need to include each of the cross routes with structures and those that may warrant structures in the future.

Study Process

The corridor study process, shown in theĀ  diagram below, is divided into 5 steps:

  • Current and Future Conditions: SDDOT will review current traffic operations, roadway pavement conditions, and crashes to characterize where issues currently exist. Additionally, traffic will be projected to 2045 and used as the basis for identifying what the future may look like.
  • Define Design Criteria: Ideas of what needs to be built or rebuilt in the corridor and how changes may look requires a set of criteria regarding the role various routes play in the network and how routes may look to support the role.
  • Develop Concepts: The SDDOT will identify a series of intersection and segment improvements that directly address resolving deficiencies observed today and through the 2045 horizon year.
  • Screen Alternatives: The SDDOT will apply a set of evaluating measures in reviewing the range of alternatives so there is consistency in the process of defining what needs to be built and/or rebuilt.
  • Proposed Improvements: The product of the study will be a list of improvements that address condition, operations and safety deficiencies in the corridor. These will include improvements to I-29 and cross routes to the interstate.