"Authorized emergency vehicle" means any vehicle of any fire department, police department, sheriff's office, coroner, prosecuting attorney, Washington state patrol, ambulance service, public or private, which need not be classified, registered or authorized by the state patrol, or any other vehicle authorized in writing by the state patrol.
RCW 46.04.040
Construction-Application of rules-Severability-1987 c 330: See notes following RCW 28B.12.050.