The Hood Canal floating bridge closes May 1 for a six-week project to replace the eastern half of the bridge.
The Transportation Department has been urging travelers between the Kitsap and Olympic peninsulas to prepare for the disruption.
The $500 million project will replace pontoons and make other improvements on the older half of the bridge that opened in 1961.
The Transportation Department says the 8,869-foot bridge is the longest floating bridge in the world over saltwater.
The Associated Press