Only official traffic control signs may be placed in the state highway right-of-way. All other signs, including campaign signs, are prohibited and may be removed by Washington State Department of Transportation (WSDOT) maintenance crews.

Temporary political signs are allowed on private property with no fee or permit requirement. For a campaign sign to be legally posted such that it is visible from a state highway, the property owner must give consent, and the signs must comply with state and local requirements.

WSDOT advises that utility poles are typically located inside and near the edge of right-of-way and that fence lines are often at the edge of right-of-way, to separate the right-of-way from private property. If a campaign sign is located between a utility pole and the paved edge of the roadway or on the highway side of a parallel fence line, it will most likely be removed.

WSDOT must develop and maintain a publicly available map that indicates all locations where temporary political campaign signs are permitted to be placed along any main-traveled way of the interstate system, primary system, or scenic system across the state. The map must include:

• all department-owned or managed land;
• all locations where signs are prohibited because of a state highway right-of-way;
• any adjoining private or public land where signs are not prohibited due to proximity to an interstate system, primary system, scenic system, or state highway right-of-way; and
• any department-owned or managed land where signs are permitted.

The map must be available on WSDOT's website and prominently placed for public access.

WSDOT may not remove any sign unless the map indicates that the sign is placed in a prohibited area.