DEPARTMENT: Transportation
FILE TYPE: Regular Action
TITLE
title
Authorization To Submit Recommended Design Alternative To Minnesota Department Of Transportation For Interchange Improvements At County State Aid Highway 50/5 And Interstate 35 In City Of Lakeville, County Project 50-33
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PURPOSE/ACTION REQUESTED
Receive an update and authorize submittal of the staff-recommended design alternative to the Minnesota Department of Transportation (MnDOT) to improve the County State Aid Highway (CSAH) 50/5 interchange with Interstate 35 (I-35) in the City of Lakeville.
SUMMARY
To provide a safe and efficient transportation system, staff proceeded with work on County Project 50-33 under Contract No. DCA21560, authorized by Resolution No. 24-204 (April 23, 2024), which also confirmed the use of State of Minnesota grant funds to reimburse contract costs. The project is consistent with the adopted Capital Improvement Program and project development needs at the junction of I-35 and CSAH 50/5 in Lakeville (Attachment: Project Location Map). County Project 50-33 will address roadway safety and mobility needs at the major junction, including replacement of County and City roadway infrastructure and bridges. Limited reconstruction along I-35 will also be included.
County staff presented a project update to the Physical Development Committee on November 19, 2024, reporting on preliminary design work underway in partnership with the City of Lakeville and the Minnesota Department of Transportation (MnDOT). The interchange project is planned for 2028-2029 construction, with current project management goals addressing the need to submit a recommended geometric layout to MnDOT for review by February 1, 2025, as encouraged by Minn. Stat § 161.178 Transportation Greenhouse Gas Emissions Impact Assessment.
County staff and the consultant have now completed further studies of project alternatives and held the second public open-house meeting on December 19, 2024. Continued public outreach has also included communications with owners and tenants adjacent to the interchange project area.
The recent presentations to the Physical Development Committee, to local and state elected officials, and to the public have focused on two interchange design alternatives (Attachment: Interchange Alternative Layouts). The two alternatives are:
• The Modernized Diamond, which includes a new 174th Street local-roadway connection, closing 175th Street access east CSAH 50, as first mapped in recommendations from 2004 by Dakota County and City of Lakeville.
• The Diverging Diamond, which includes an improvement to the existing 175th Street local roadway connection east of CSAH 50. This alternative includes options for routing pedestrian/bicyclist trails through the interchange under the I-35 bridges, with trails on the sides of CSAH 50 or a single trail in the center median of CSAH 50.
Based on detailed review of preliminary design alternatives, staff recommend submitting the Diverging Diamond interchange alternative to MnDOT for further technical review by February 1, 2025. The submitted design will be formatted as a study layout following MnDOT procedures and will include one of the two trail-routing options based on further review. The recommended design will be subject to further study and revisions after the MnDOT submittal, will be presented in funding program applications, and will be subject additional formal approvals. Staff recommend the Diverging Diamond alternative because it will provide a more efficient and safer layout for increasing traffic using the interchange compared to the Modernized Diamond and to other alternatives considered. The Diverging Diamond alternative also helps to limit property impacts and construction costs.
The recommended study layout will include modifications to other intersections on the CSAH 50/5 corridor, will add auxiliary lane capacity along northbound I-35, and will address the feasibility and recommendations for multi-use trail routings and crossing features. Staff will facilitate additional reviews and stakeholder outreach as more details are determined for the project’s recommended design, cost estimate, funding sources, and approval issues. Additional County Board updates or approvals will be included when necessary.
RECOMMENDATION
recommendation
The County Engineer recommends authorizing submittal of the staff-recommended design alternative as a study layout to MnDOT to improve the CSAH 50/5 interchange with I-35 in the City of Lakeville.
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EXPLANATION OF FISCAL/FTE IMPACTS
The 2024 Transportation Capital Improvement Program Adopted Budget included an approved budget in the amount of $6,240,000. State of Minnesota Local Road Improvement Program (LRIP) Grant funds were awarded to Dakota County in a 2021 state appropriation, and $1,466,232 from the LRIP Grant was applied to the current consultant contract under a reimbursable program (Dakota County Contract No. DCA21726 with MnDOT). A federal earmark of $5.04M was also awarded to County Project 50-33 in 2023 and must be matched with 20 percent of local funds and obligated by September 30, 2026. Additional funding sources will be pursued to address costs through construction planned for 2028-2029. Preliminary construction estimates projected to 2028 range from approximately $50 million to $60 million, not including right-of-way costs.
☐ None ☒ Current budget ☐ Other
☐ Amendment Requested ☐ New FTE(s) requested
RESOLUTION
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WHEREAS, to provide a safe and efficient transportation system, Dakota County is proceeding with County Project (CP) 50-33; and
WHEREAS, CP 50-33 includes the preliminary engineering design of improvements at the interchange of County State Aid Highway 50 (CSAH 50) and Interstate 35 (I-35) in Lakeville; and
WHEREAS, the interchange project is planned for 2028-2029 construction, with current project management goals addressing the need to submit a recommended geometric layout to the Minnesota Department of Transportation (MnDOT) for review by February 1, 2025, per Minn. Stat § 161.178 Transportation Greenhouse Gas Emissions Impact Assessment; and
WHEREAS, County staff and engineering consultants have completed technical studies of project alternatives, working with the City of Lakeville and MnDOT, and completed two public meetings on September 9 and December 19, 2024; and
WHEREAS, County, City, and MnDOT staff evaluated efficient and safe service for increasing traffic when evaluating design alternatives, as well as other criteria including opportunities to limit property impacts and construction costs; and
WHEREAS, Staff recommend submitting the Diverging Diamond interchange alternative to MnDOT for further technical review by February 1, 2025, formatted as a study layout following MnDOT procedures.
NOW, THEREFORE, BE IT RESOLVED, That the Dakota County Board of Commissioners hereby authorizes the County Engineer to submit the Diverging Diamond interchange alternative to the Minnesota Department of Transportation for further technical review by February 1, 2025, formatted as a study layout.
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PREVIOUS BOARD ACTION
24-204; 4/23/24
ATTACHMENTS
Attachment: Project Location Map
Attachment: Interchange Alternative Layouts
Attachment: Presentation Slides
BOARD GOALS
☒ A Great Place to Live ☐ A Healthy Environment
☐ A Successful Place for Business and Jobs ☐ Excellence in Public Service
CONTACT
Department Head: Erin Laberee
Author: Doug Abere