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SR 509, I-5 to 24th Avenue South – Expressway Project – Project Overview

What is included in the project?

Key features of the SR 509, I-5 to 24th Avenue South – Expressway Project include:

  • Reconstructing the I-5/SR 516 interchange
  • Building a new roadway, parallel to I-5, that connects SR 509 to Veterans Drive in Kent
  • Providing new access via Veterans Drive and a new northbound lane on I-5 between the interchange with SR 516 and the new I-5/SR 509 connection.
  • Building a new South 216th Street bridge over I-5
  • Building new and extending existing noise walls
  • Constructing new ramps that connect I-5 and SR 509 and the first mile of the new SR 509 Expressway
  • Constructing a new interchange at 24th Avenue South

Project timeline

The SR 509, I-5 to 24th Avenue South Expressway Project is the second construction contract (Stage 1b) of the SR 509 Completion Project. Construction will begin in late 2021 and end in 2025. WSDOT will complete the SR 509 Completion Project with a third construction contract (Stage 2) between 2024 and 2028. Stage 1a, which includes a new SR 99 bridge is currently under construction as part of Sound Transit’s Federal Way Link Extension light rail project.

A timeline displaying phases of work for the SR 509 completion project
The contractor is finalizing design and will start construction this year (2021). Major construction will start in 2022 and take about four years to complete.