Wash. Rev. Code § 46.44.140
In addition to any other special permits authorized by law, special permits may be issued by the department of transportation for a quarterly or annual period upon such terms and conditions as it finds proper for the movement of (1) farm implements used for the cutting or threshing of mature crops; or (2) other farm implements that may be identified by rule of the department of transportation. Any farm implement moved under this section must comply with RCW 46.44.091, have a gross weight of less than sixty-five thousand pounds, and have a total outside width of less than twenty feet while being moved, and such movement must be patrolled, flagged, lighted, signed, at a time of day, and otherwise in accordance with rules hereby authorized to be adopted by the department of transportation for the control of such movements.
Applications for and permits issued under this section shall provide for a description of the farm implements to be moved, the approximate dates of movement, and the routes of movement so far as they are reasonably known to the applicant at the time of application, but the permit shall not be limited to these circumstances but shall be general in its application except as limited by the statutes and rules adopted by the department of transportation.
A copy of the governing permit shall be carried on the farm implement being moved during the period of its movement. The department shall collect a fee as provided in RCW 46.44.0941.
Violation of a term or condition under which a permit was issued, of a rule adopted by the department of transportation as authorized by this section, or of a term of this section is a traffic infraction.
RCW 46.44.140
Effective date-Severability-1979 ex.s. c 136: See notes following RCW 46.63.010.