WSDOT is starting construction on the SR 509, I-5 to 24th Avenue S. – Expressway Project in 2022. This project is part of WSDOT’s effort to extend the SR 509 highway from where it currently ends by Sea-Tac International Airport to Interstate 5.
How to participate
This online open house details the project’s key features and benefits. It also provides an opportunity to share your feedback. Please visit each page to learn more about the project and make any comments on the Comments and Survey Page. We also hope you will take a few minutes to complete the brief survey on that same page.
This online open house will remain active between January 25 and March 5, 2021.
What is the SR 509 Completion Project?
The SR 509, I-5 to 24th Avenue S. – Expressway Project is part of the greater SR 509 Completion Project, scheduled for completion in 2028. The SR 509 Completion Project will ultimately extend SR 509 to I-5 in SeaTac and add a southern access route to Sea-Tac International Airport to allow drivers to bypass I-5, SR 518, and local streets.
When finished, SR 509 will provide new access to the airport and will help get freight off local streets. Along with the SR 99 tunnel improvements, WSDOT will provide a critical north-south alternative to I-5 through Seattle and King County.