SR 527 became a state highway during the 1964 highway renumbering, in which the Washington State Department of Transportation (WSDOT) replaced the previous system of Primary and Secondary Highways with a new system called State Routes, which is still in use today.
SR 527 became a state highway during the 1964 highway renumbering. The Washington State Department of Transportation (WSDOT) replaced the previous system of Primary and Secondary Highways with a new system. This new system was called State Routes in the 1964 highway renumbering. State Routes is still in use today.