I-90 Exit 46 (Elk Creek Road) Interchange Modification Study

Reason for Study:

The 2000 Intestate Corridor Study determined that the I-90 corridor between Black Hawk and Sturgis would be one of the top segments of South Dakota's Interstate System to target for improvement. The SDDOT responded by having the Interstate 90 Black Hawk - Sturgis Corridor Preservation Study completed in 2004, which determined that relocating the I-90 Exit 46 (Elk Creek Road) interchange would be the best alternative to prepare I-90 for future expansion. In 2008, an Environmental Assessment (EA) of Exit 40 to Exit 51 confirmed the need to relocate the interchange in preparation of future mainline I-90 expansion and determined a diamond configuration to be the preferred alternative for that relocated interchange.

The SDDOT has been making progress implementing the recommendations from the Interstate 90 Black Hawk - Sturgis Corridor Preservation Study. As part of that progression, the SDDOT has reached the milestone to conduct a more in depth study of the Exit 46 interchange's traffic operations, affects to the Interstate System, and request permission from the Federal Highway Administration (FHWA) to make modifications to the Elk Creek Road interchange.


Study Limits:

The study improvement corridors for the I-90 Exit 46 (Elk Creek Road) Interchange Modification Study will include:
  • Elk Creek Road from the intersection with Sturgis Road to the intersection with Glenwood Drive, approximately 0.70 miles,
  • Deer View Road from Sturgis Road to Spring Valley Road, approximately 0.75 miles,
  • Stage Stop Road from Sturgis Road to La Rue Road, approximately 0.80 miles,
  • Mainline I-90 from west of I-90 Exit 44 to east of I-90 Exit 48, approximately 4 ½ miles,
  • The ramps for the I-90 Exit 46 (Elk Creek Road) interchange,
  • The ramps for the I-90 Exit 44 (Bethlehem Road) interchange, and
  • The ramps for the I-90 Exit 48 (Stage Stop Road) interchange.
Map of Study Area


Public Involvement

The South Dakota Department of Transportation (SDDOT) has a long history of public involvement in the development of transportation plans and projects. The 2005 passage of the Safe, Accountable, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU) requires a public involvement process. In accordance with the Department's public participation document, the I-90 Exit 46 (Elk Creek Road) Interchange Options Study strives to keep the public involved with the study as much as possible. Public meetings for the study will occasionally be scheduled to collect public input, provide information and answer questions.

Public Meeting #1 - January 20, 2016

Business/Landowner Group Meetings
Given the commercial importance of the Elk Creek Road corridor and the impact improvements along the corridor could have on businesses along the corridor, separate meetings with groups of business owners and landowners along the corridor will be held.


Study Advisory Team:

Given the importance of the corridor and the potential for future development within and north of the corridor's influence area, the SDDOT has established a study advisory team to help provide input from differing points of view. The study advisory team comprises of representatives from the SDDOT, the City of Rapid City, and the Federal Highway Administration. The study advisory team will meet throughout the study period

Study Technical Memorandums:


Links to Previous Studies:


The SDDOT has retained Felsburg, Holt, & Ullevig, Inc. to perform this study. For more information or comments, please contact:


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Steve Gramm
Planning Squad Leader
605-773-3281
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