Crews installed high-tech electronic signs on I-90 and SR 520 between Seattle and Bellevue.
WSDOT crews installed a series of electronic speed-limit and lane status signs over each lane on the SR 520 and I-90 bridges over Lake Washington. They include:
- SR 520 - There are 19 sign locations between I-5 and 130th Ave NE in Bellevue. This includes new sign bridges and signs that will be mounted on existing structures.
- I-90 - There are 25 sign locations between I-5 and 150th Avenue SE. This also includes new sign bridges and signs that will be mounted on existing structures.
The signs post variable speed limits that help warn drivers of backups ahead and smooth out traffic as it approaches a lane blocking incident. The overhead signs can also quickly close entire lanes and provide warning information to drivers before they reach slower traffic.
This advance notification and variable speed limits helps reduce collisions that cause backups and stop-and-go traffic.
The SR 520/I-90 Active Traffic Management Project helps make these cross-lake corridors safer by reducing the numbers of congestion-related collisions, such as side-swipe or rear-end collisions.
Active traffic management tools have proven effective at reducing collisions and improving traffic flow in Europe. This technology has resulted in several benefits including a 30 percent reduction in injury collisions.
Partnerships & Cooperation
This safety project is an important part of the Lake Washington Urban Partnership, which is a partnership between WSDOT, King County and the Puget Sound Regional Council.
This $42 million federally funded program is financed through the FHWA Urban Partnership .
Jennifer Charlebois, P.E.
WSDOT Project Engineer
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