Tamarack Road/I-494 Interchange

Woodbury, Minnesota

To reduce congestion of the rapidly growing area, the City of Woodbury asked SRF to design an interchange at I-494 and Tamarack Road. This $12 million project included a four-lane divided roadway and a bridge over I-494. Before beginning the interchange design, SRF performed a comprehensive update to the original I-494 Access Study – we updated previous traffic forecasts and operations analyses to confirm the need for the interchange. The analyses also included the proposed reconstruction of the I-494 interchange at TH 120/Valley Creek Road to the south.

The proposed interchange design and roadway geometrics were developed to optimize the traffic operations and reduce delays. Intersection analyses and freeway weaving conditions were thoroughly studied to quantify the future condition of the roadway.

SRF also documented changes in environmental conditions via a revised Study Report and prepared new interchange access request documents for the Metropolitan Council and the Federal Highway Administration.

Because of the wetlands and a sensitive stand of tamarack trees that border the interstate, the roadway system was aligned to the north and the bridge was extended 300 feet to avoid impacts to the swamp. During the design phase, SRF also coordinated with multiple agencies, including the City of Woodbury, MnDOT, and Corps of Engineers.

The I-494/Tamarack Road interchange provided additional freeway access connecting a significant east-west arterial roadway through Woodbury to the interstate system. The project efficiently balanced traffic demands on the local roadway system, resulting in reduced travel time and congestion and safer traffic operations.

Well thought-out design and construction staging strategies and a comprehensive set of plans and specifications led to a construction bid $2 million below estimated construction costs. The cost savings enabled the City of Woodbury to construct several additional roadways adjacent to the interchange.

This project exemplifies blending science, agency participation and innovative design to meet the needs of the community while protecting the environment.




  • 2004 MSPE Seven Wonders of Engineering Award

CLIENT: City of Woodbury