I-29 Exit 133 Interchange Interchange Modification Study

The South Dakota Department of Transportation (SDDOT), in conjunction with the City of Brookings, is conducting an Interchange Modification Study of Exit 133 on Interstate 29. This interchange provides access to the U.S. Highway 14 Bypass.

About

Due to increasing traffic and anticipated development along the U.S. Highway 14 Bypass, SDDOT plans to reconstruct the Interstate 29 Exit 133 interchange and a portion of the Highway 14 Bypass through the interchange as part of a planned project beginning in Fiscal Year 2029.

The 2020 Highway 14 – Highway 14 Bypass Corridor Study recommended that variations of a Modified Diamond Interchange be carried forward to this Interchange Modification Study for further refinement and evaluation. A Modified Diamond Interchange is very similar to the current interchange layout. However, the northbound off-ramp and on-ramp are shifted west to increase spacing between the northbound ramp terminal intersection and the 32nd Avenue intersection.

This study will determine the type and configuration of the future I-29 Exit 133 interchange, the number of lanes on the U.S. 14 Bypass reconstruction for the planned project.

Modified Diamond Interchange Alternatives from U.S. 14 – U.S. 14 Bypass Corridor Study

Alternatives will be refined as part of this study.

Quick Info

Study Goals

Create Interchange Modification Justification Report (IMJR) for the Federal Highway Administration (FHWA)
Use the transportation planning decisions and analysis, including purpose and need, identification of preliminary alternatives, and elimination of unreasonable alternatives, to inform NEPA. Document this planning information and decisions through the creation of an Environmental Screening Report (ESR) that allows decisions made in planning to be carried forward into the environmental review and National Environmental Policy Act (NEPA) processes.
Provide guidance to implement recommended improvements for future construction

Key Considerations

Stakeholder and Public Input
Constructability
Access Management
Traffic Operations
Long-Range Strategic Planning

Study Area Map

Click below to enlarge the Study Area Map.

Schedule

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Public Involvement

Public Meeting Open House

The DOT has held two public open house meetings for this project. These events were used to share project updates and receive feedback from the community. The first one was held in March 2023 and the second in November 2023. Below you can review the materials from both of these public open house meetings.