Traffic Impacts for Final Phase of H-Frame System Upgrades

Drivers using I-5 and State Route 900 near Boeing Field should plan for delays and prepare to use alternate routes as Seattle City Light crews work to replace overhead utilities that span the busy highways on Fri., Oct. 24 to Sat., Oct. 25. To complete this work, City Light’s traffic control contractor will close both directions of I-5 between SR 599 and Boeing Access Road, and MLK Way (SR 900) between S 129th St and Boeing Access Road. The highway closures will provide crews with the space they need to safely replace an overhead communication and lightning protection cable.

(Traffic Impact Map for Fri., Oct. 24- Sat., Oct 25)

Closure details

Fri., Oct. 24 to Sat., Oct. 25  

  • Traffic closures on both directions of I-5 between SR 599 and Boeing Access Road and SR 900 (MLK Way). The first lane will close at 9 p.m.  All lanes will be closed by midnight and reopen by 6 a.m.
  • Both directions of MLK Way (SR 900) will be closed between S 129th St and Boeing Access Road from 11 p.m. to 6 a.m. 
  • The Interurban Avenue on-ramp to northbound I-5 and the Corson Avenue on-ramp to southbound I-5 will also be closed between 10 p.m. and 6 a.m.    

 Signed detour routes will be provided. Drivers are advised to carefully follow traffic detour routes and consider using alternate routes during construction.

City Light is working to increase the electrical capacity and reliability to the Duwamish Valley with the H-Frame Replacement and Feeder Installation Project. This is the final phase of construction to replace eight outdated H-Frame structures and cables that transmit electricity on high voltage lines across I-5 due to their age and increasing electricity demand. The project will improve system safety and increase electrical reliability for customers. For more information about this project and other City Light construction projects, please visit