I-29 Corridor Study

The Interstate 29 Corridor in the northwest reaches of the Sioux City metropolitan area serves the state of South Dakota and its local communities. We have the opportunity through an I-29 Corridor Study to establish a long-term plan that both modernizes the corridor while maintaining its versatility.

Study Background

The Interstate 29 (I-29) Corridor Study covers Union County, South Dakota, and includes portions of the interstate, interchanges, and cross streets within the urban boundary for the communities of North Sioux City and Dakota Dunes.

Over 11 miles of I-29 is due for major rehabilitation or reconstruction in the 2030 to 2035 timeframe. Past studies have identified the need for potential interchange improvements at exit 1 (Dakota Dunes Boulevard), exit 2 (River Drive), and exit 4 (Northshore Drive).

A potential exit 5 interchange was added to the I-29 Corridor Study in response to recent flooding events near exit 4 in North Sioux City. A possible location for the exit 5 interchange is being evaluated to enhance resiliency and provide an alternative route during future flooding events.

An implementation schedule is needed for I-29 construction projects throughout the corridor. An initial public meeting was held in 2023 to gather public feedback on the corridor vision and exits.

Interstate 29 Corridor Study Project Locations

I-29 between Exit 2 and 4, 4 and 5, 5 and 9, and 9 to the project limits

Cross-Section: Maintain existing urban 4-lane divided freeway
Description: Rehabilitation of pavement along I-29
Traffic Operations Year of Congestion: 2090, except for 2070 for exit 2 or 4
Pavement/Bridgework needed in next 5 years: No
Cost for between exit 2 and 4: $19.9 million to $29.8 million
Cost for between exit 4 and 5: $13.5 million to $20.3 million
Cost for between exit 5 and 9: $37.2 million to $55.7 million
Cost for between exit 9 and project limits: $21.5 million to $32.3 million

330th Street / I-29 Interchange (Exit 9)

Cross-Section: Maintain existing urban 4-lane divided freeway
Description: Modify ramp configurations for safety. Address when pavement on I-29 declines near Exit 9.
Traffic Operations Year of Congestion: 2090
Pavement/Bridgework needed in next 5 years: No
Cost: To be determined

Westshore Drive / I-29 Interchange (Exit 5)

Cross-Section: Maintain existing urban 4-lane divided freeway
Description: Rehabilitation of Westshore Drive bridge. New interchange remains as a design alternative.
Traffic Operations Year of Congestion: 2090
Pavement/Bridgework needed in next 5 years: No
Cost: To be determined

Northshore Drive / I-29 Interchange (Exit 4)

Cross-Section: Maintain existing urban 4-lane divided freeway
Description: Reconstruct interchange to improve traffic flow and safety. Modify ramp configurations and signalize intersections as needed. Remaining interchange improvements include relocation of interchange north.
Traffic Operations Year of Congestion: 2035
Pavement/Bridgework needed in next 5 years: No
Cost: $62 million to $88 million

River Drive in North Sioux City

Cross-Section: To be determined
Description: Improve River Drive to support local access needs and enhance connectivity to I-29. Consider intersection modifications for better traffic flow.
Traffic Operations Year of Congestion: 2030
Pavement/Bridgework needed in next 5 years: No
Cost: To be determined

I-29 Exit 1 to Exit 2

Cross-Section: 6-lane divided - Urban Freeway
Description: Reconstruct and widen I-29 to accommodate projected traffic volumes. Improve pavement conditions and address operational deficiencies by adding auxiliary lanes.
Traffic Operations Year of Congestion: 2075
Pavement/Bridgework needed in next 5 years: Yes
Cost: $18.4 million to $27.6 million

I-29 - Big Sioux River Bridges

Cross-Section: 6-lane divided - Urban Freeway
Description: Reconstruct and widen Big Sioux River Bridges to improve structural capacity and accommodate future traffic needs.
Traffic Operations Year of Congestion: 2035
Pavement/Bridgework needed in next 5 years: Yes
Bridge Cost: $18.4 million to $27.6 million
Total Cost: $39.1 million to $58.6 million

Northshore Drive in North Sioux City

Cross-Section: Collector/Arterial to I-29 Freeway
Description: Improve Northshore Drive to support local access needs and enhance connectivity to I-29. Consider intersection modifications for better traffic flow. The Northshore Bypass Project is also included for updates in this area.
Traffic Operations Year of Congestion: 2035
Pavement/Bridgework needed in next 5 years: No
Cost: $22 million to $25 million (not including Northshore Bypass Project)

River Drive / I-29 Interchange (Exit 2)

Cross-Section: 6-lane divided - Urban Freeway
Description: Reconstruct interchange to improve traffic flow and safety. Modify ramp configurations and signalize intersections as needed. Improvements for interchange area include improvements to North Derby Lane.
Traffic Operations Year of Congestion: 2030
Pavement/Bridgework needed in next 5 years: No
Cost: $13 million to $45 million

Dakota Dunes Boulevard / I-29 Interchange (Exit 1)

Cross-Section: 6-lane divided - Urban Freeway
Description: Reconstruct interchange to improve traffic flow and safety. Modify ramp configurations and signalize intersections as needed.
Traffic Operations Year of Congestion: 2023
Pavement/Bridgework needed in next 5 years: No
Cost: $37 million to $59 million

Interstate 29 Corridor Study Area

Study Objectives

The need for this study was identified by the Study Advisory Team (SAT), which is comprised of state, regional, local, and federal agencies, based on a number of factors. The SAT and project team have established the following objectives for the study:

Determine a future vision for I-29 mainline infrastructure

Determine potential interchange concepts that meet study advisory team objectives

Create an implementation schedule for I-29 construction projects throughout the corridor

Prepare partner agencies for future environmental study, permitting, and design

Schedule

Project Kickoff - January 2023
Corridor Vision Complete - May 2023
Exit 1, Exit 2 and Exit 4 Stakeholder and Public Meeting #1 - July 2023
Corridor Needs Complete - November 2023
Solutions Identification Complete - January 2024
Design Concepts Complete (Exits 1 and 2) - May 2024
Flooding Event Near Exit 4 - June 2024
Regional Priorities Took Precedence over I-29 Study - Summer 2024
Coordination of Northshore Bypass/Exit 4 Next Steps - Fall 2024
Exit 5 Kickoff - January 2025
Exit 5 Concept Design - Ongoing 2025
Exit 5 Stakeholder and Public Meeting #1 (Public Feedback on Design) - September and October 2025
Public Meeting #2 (Feedback on I-29 Mainline and All Cross-Streets Exits) - February and March 2026
Study Recommendations on Design and Construction Sequences - April 2026
I-29 Corridor Study Completion - May 2026

Get Involved

Upcoming Events

There are no upcoming events at this time.

Exit Concepts

Past Events

A public meeting open house was on Thursday, Oct. 9, 2025, at the North Sioux Community Center in North Sioux City, SD. The goal of this meeting was to share design options for the I-29 corridor, allow the public the opportunity to collaborate with the project team on the design options, and provide information about future corridor projects and development. This input will help the study team to document key community needs to address in design and to validate the timeline for future infrastructure projects associated with I-29.

Archived Meeting Materials