Wash. Rev. Code § 47.52.131
When the department is planning a limited access facility through a county or an incorporated city or town, the department or its staff, before any hearing, shall give careful consideration to available data as to the county or city's comprehensive plan, land use pattern, present and potential traffic volume of county roads and city streets crossing the proposed facility, origin and destination traffic surveys, existing utilities, the physical appearance the facility will present, and other pertinent surveys and, except as provided in RCW 47.52.134, shall submit to the county and city officials for study a report showing how these factors have been taken into account and how the proposed plan for a limited access facility will serve public convenience and necessity, together with the locations and access and egress plans, and over and under crossings that are under consideration. This report shall show the proposed approximate right-of-way limits and profile of the facility with relation to the existing grade, and shall discuss in a general manner plans for landscaping treatment, fencing, and illumination, and shall include sketches of typical roadway sections for the roadway itself and any necessary structures such as viaducts or bridges, subways, or tunnels.
Conferences shall be held on the merits of this state report and plans and any proposed modification or alternate proposal of the county, city, or town in order to attempt to reach an agreement between the department and the county or city officials. As a result of the conference, the proposed plan, together with any modifications, shall be prepared by the department and presented to the county or city for inspection and study.
RCW 47.52.131