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SR 99 - Intelligent Transportation Systems - Complete July 2011

Project Status - Complete
SR 99 Intelligent Transportation Systems Project Map View the entire project map.

The viaduct looking south.

Real-time traffic information tools will be operational by December 2010, before crews start significant construction of the Alaskan Way Viaduct replacement.

In January 2010, WSDOT began work to bring more real-time traffic information to drivers on SR 99, and major routes leading to SR 99 in Seattle.

As part of this work, WSDOT added:

  • More cameras to monitor traffic and locate collisions so we can clear them more quickly and reroute traffic if necessary.
  • Overhead electronic message boards like the ones you see on state highways to let you know what's happening ahead.
  • New signal timing equipment that can automatically adjust to traffic flow to get more vehicles moving on SR 99.

Highway 99 parallels I-5 and is frequently used as the route to get people and goods into and out of downtown Seattle.

Installing real-time traffic information systems now will help keep traffic moving during construction to replace the double-deck viaduct in the near future. These systems will continue to move traffic smoothly long after the viaduct is replaced.

Project timeline

  • December 2009 - Project work in both sections awarded to Signal Electric, Inc. from Kent
  • January 2010 - Construction begins on northern and southern sections of the project
  • December 2010 - Southern section of the project completed.
  • Summer 2011 - Northern section of the project completed

How You Benefit
Car GlyphRelieves Congestion
Traffic cameras and overhead electronic message signs will help keep drivers informed of backups and incidents that may affect traffic. Improved signal timing on SR 99 will more evenly distribute traffic, reducing congestion during busy times.

Partnerships & Cooperation
WSDOT and the Seattle Department of Transportation (SDOT) are working together to keep traffic and freight moving during construction of the Alaskan Way Viaduct replacement.


Financial Data for PIN 809936W
Funding Source Amount ($ in thousands)
2003 Gas Tax (Nickel Funding) $0
2005 Gas Tax (TPA) $2,539
Pre-Existing Funds (PEF) $12,655
Total $15,194

The SR 99 Intelligent Transportation Systems project is funded as part of WSDOT's Alaskan Way Viaduct and Seawall Replacement Program

  • Preliminary engineering: $2.5 million.
  • Construction: $9 million
  • Total available funding: $11.5 million

Contact Us
For questions about work happening north of the Duwamish River on SR 99 between E. Marginal Way S. (SR 99) to N. 145th Street in Shoreline, please contact:

Project Engineer John Chi
1715 228th St SE #106
Bothell, WA 98021-8445
Phone: 425-489-5402

If you have questions about work happening south of the Duwamish River on routes SR 99, SR 509 and SR 599, please contact:

Project Engineer Dave Lindberg
WSDOT Construction Office
Phone: 206.521.5624

You may also contact our public information officer:

Communications Broch Bender
Telephone: 206-805-2817
Information hotline: 1-888-AWV-LINE (1-888-298-5463)

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