Washington Revised Code Title 47. Public Highways and Transportation § 47.36.180. Forbidden devices--Penalty

(a) Visible from a city street, county road, or state highway and simulating any directional, warning, or danger sign or light likely to be mistaken for such a sign or bearing any such words as “danger,” “stop,” “slow,” “turn,” or similar words, figures, or directions likely to be construed as giving warning to traffic;

(b) Visible from a city street, county road, or state highway and displaying any red, green, blue, or yellow light or intermittent or blinking light or rotating light identical or similar in size, shape, and color to that used on any emergency vehicle or road equipment or any light otherwise likely to be mistaken for a warning, danger, directional, or traffic control signal or sign;

(c) Visible from a city street, county road, or state highway and displaying any lights tending to blind persons operating vehicles upon the highway, city street, or county road, or any glaring light, or any light likely to be mistaken for a vehicle upon the highway or otherwise to be so mistaken as to constitute a danger; or

(d) Visible from a city street, county road, or state highway and flooding or intending to flood or directed across the roadway of the highway with a directed beam or diffused light, whether or not the flood light is shielded against directing its flood beam toward approaching traffic on the highway, city street, or county road.