Contractor resources

Project delivery

WSDOT will manage project construction for the I-90 - SR 18 Interchange Improvements and Widening project through a design-build contract. With design-build, we execute a single contract with one entity (the design-builder) for design and construction services. Please note the preferred alternative selected by WSDOT includes a diverging diamond interchange and widening SR 18. This includes a "base scope" option, and two "base scope plus" options. More information about the base scope, the base scope options, deadlines and more project and contract information is available on the project's contract ad and award webpage. 

Procurement schedule

  • Request for Qualifications (RFQ) issued: June 30, 2020
  • Statement of Qualifications due: Aug. 27, 2020
  • Request for Proposals issued: Oct. 21, 2020
  • Proposals due: Jan. 26, 2021
  • Announce Apparent Best Value Proposer: March 17, 2021
  • Estimated Notice To Proceed (NTP): April 21, 2021

*Please note these dates are approximate and subject to change

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Additional resources

WSDOT Contracts and Awards:
To request project materials like plans and surveys, please visit:


General contractor information

Project information