Special Studies
Statewide Studies
Expressway Feasibility Studies
Eastern Dakota and Pierre to I-90 Expressway Executive Summary
Eastern Dakota and Pierre to I-90 Expressway Feasibility Complete Study
Interchange Justification Studies
I-29 Exit 75 / I-229 Exit 1A and 1B (System Interchange; Sioux Falls)
I-90 Exit 396/I-29 Exit 84 (System Interchange; Sioux Falls)
I-90 Exit 400/I-229 Exit 10 (System Interchange; Sioux Falls)
Corridor Studies
Decennial Studies:
2010 Decennial Interstate Corridor Study Phase 1 Final Report (16MB)
2010 Decennial Interstate Corridor Study Phase 2 Final Report (12MB
2010 Decennial Interstate Corridor Study Phase 3 Final Report (10MB)
2020 Decennial Interstate Corridor Study Phase 3 Report
Local Studies:
Interstate Studies:
I-229 Major Investment Corridor Study
I-190 Corridor / Silver Street Interchange Study in Rapid City
Highway Studies:
S.D. Highway 115 Corridor Study
U.S. 14/U.S. 83/S.D. 34 Missouri River Bridge Replacement Study
U.S. Highway 14A (Colorado Boulevard) Corridor Study Including I-90 Exit 14 in Spearfish
U.S.16 (Mount Rushmore Road/8th Street) Corridor Study through Rapid City
Area Studies
Vermillion Pavement Management Plan (Coming Soon)
No Current Studies
Studies without a link are available upon request from the planning squad leader below.
Contacts
© 2026 State of South Dakota. All Rights Reserved.
Becker-Hansen Building
700 E. Broadway Ave.
Pierre, SD 57501
Modern Logic
Region & Area Offices
Travelers
© 2026 State of South Dakota. All Rights Reserved.
Becker-Hansen Building
700 E. Broadway Ave.
Pierre, SD 57501
Modern Logic
