Seattle ATMS i-5/I-90/SR-520

Smooths traffic flow and reduces rear-end crashes.

Quick Facts

  • One of the first Active Traffic Management Systems (ATMS) in US

  • Spans three major freeways in Seattle and Bellevue area: I-5 northbound, SR 520, and I-90 eastbound

  • Includes variable speed limit signs, variable message signs, and lane-use control

  • Includes nearly 300 dynamic message signs


  • The ATMS informs motorists of closures, changes in lane configurations, and traffic incidents along the freeways leading into downtown Seattle

  • Total collisions are down 6.5% to 8.5% compared to other similar freeways

Our Work

  • Served as lead design firm responsible for the design of field devices, software and the communications network used by WSDOT to manage freeways leading into downtown Seattle

  • Prepared systems engineering documents and the test plan for all new devices

  • Communications: Designed fiber backbone to provide center-to-field communications, including the fiber splices, field connections for each device, and the Ethernet communications network

  • Signs: Designed the installation of over 250 signs using a combination of sign gantries and existing structures to support the signs

  • Field Devices: Designed other field devices for management of the lane control and variable speed zone messaging used to help manage traffic flows, including CCTV surveillance cameras and vehicle speed and volume detection devices

Privacy Policy

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