SR 520 - Floating Bridge and Landings Project - Sentinel lights

What are the sentinels?

The new SR 520 floating bridge has four large towers, called “sentinels,” that mark the east and west ends of the world’s longest floating bridge. The tallest one, at the bridge’s east end, rises 123 feet above the lake’s surface. These towers not only add an architectural flair to the bridge, but also serve a critical function, allowing crews access to the bridge’s pontoon platform for maintenance.

photo of the SR 520 floating bridge at dusk, with one of its four towers, or sentinels, lighted in blue

Sentinel lighting

We illuminate the sentinels from dusk to dawn with LED lights. Teal is the standard color. Many color combinations are possible, though, which allows us to change the display color to commemorate holidays or support public events or causes of community significance.

How to request a color change

If you are interested in changing the sentinel lights for a public event or cause, please fill out our Sentinel Lighting Change Request Form (pdf 425 kb) and submit it to NWPublicAffairs@wsdot.wa.gov. Sentinel light changes are intended to recognize holidays and national and local campaigns, organizations and events of public significance. We cannot accommodate requests related to private events or political or religious events or campaigns. Details about the lighting policy and request process are listed in the request form (pdf 425 kb).