A local authority may mark or paint the surface of any street or highway under its jurisdiction, or of any state highway, with the approval of the Department of Transportation, with lines, arrows, or other suitable symbols for the purpose of directing visitors and tourists to local points of interest. No such marking shall be of a color or configuration which, as determined by the Department of Transportation, would cause it to be confused with an official traffic control device.
Ca. Veh. Code § 21374