Communications Upgrade Will Impact Traffic Sunday Morning, April 12

Drivers using state Route 99 (SR 99) just south of Boeing Field should plan for rolling slowdowns as Seattle City Light crews pull fiber optic cable over the highway Sunday, April 12, from 6 a.m. to 11 a.m.

To complete this work, City Light’s traffic control contractor will conduct a series of rolling slowdowns affecting both directions of SR 99 north and south of its intersection with South 102nd Street.  The rolling slowdowns are necessary to allow crews to safely pull the communication cable overhead in two locations without traffic underneath.

Details of Rolling Slowdowns

Sunday, April 12 from 6 a.m. to 11 a.m.

  • Up to seven 15-minute rolling slowdowns during the 5-hour period affecting both directions of SR 99/SR599 beginning southbound at its intersection with South Holden Street and beginning northbound at its intersection with I-5
  • The South Kenyon Street, South 96th Street, and Des Moines Memorial Drive South on ramps to southbound SR 99 and the South 102nd Street, Tukwila International Boulevard, and Interurban Avenue South on ramps to northbound SR 99 will be closed intermittently to ensure safety during the cable pull.
  • Drivers are advised to carefully abide by traffic restrictions and consider using alternate routes during construction. Normal traffic flow will follow once the project is complete.

City Light is enhancing the reliability of its electrical system by upgrading the communications link between two south end substations and its system control center. Besides enhancing communication capabilities by keeping the system control center in touch with substations, the new fiber optics are required to monitor lights on newly placed towers near I-5.

For more information about this project and other City Light construction projects, please visit