Detailed Design Phase of the Project

On November 17, 2017 the Federal Highway Administration (FHWA) approved implementation of a Diverging Diamond Interchange for the I-29 Exit 77 (41st Street) interchange. Then on February 23, 2018, FHWA approved the environmental documentation for the project. These steps allowed the South Dakota Department of Transportation (SDDOT) and the City of Sioux Falls (City) to move forward into the detailed design phase of the project.


A contract for detailed design services was signed on June 15, 2018 with HDR Engineering, Inc. and Confluence to perform engineering and landscaping design services, respectively, for the project.


The detailed design phase will include construction plans for the project roadways, retaining walls and bridge.


Detailed Design Phase Objectives

  • Prepare roadway and bridge plans for construction

  • Work with landowners on property purchases

  • Educate the public on how to drive the Diverging Diamond Interchange

Project Overview


Click here for a more detailed map of the project.