RCW 46.04.62250Signal preemption device.'Signal preemption device' means a device that is capable of altering the normal operation of a traffic control signal. Any such device manufactured by a vehicle manufacturer is not a signal preemption device for purposes of this section if the primary purpose of the device is any purpose other than the preemption of traffic signals and the device's ability to alter traffic signals is unintended and incidental to the device's primary purpose.[ 2005 c 183 s 1.]
Washington Legal Code