Advertisements and signs shall not be displayed within one hundred feet of any public park, state forest, playground or cemetery, or within fifteen feet from the outside line of any highway outside the thickly settled or business part of a city or town, except upon the walls of a building in which the goods advertised are offered for sale or the business advertised is conducted, and except signs erected by the state or a town or city which solely indicate highway directions, traffic regulations and dangerous places. No provision of this section shall affect any ordinance or regulation established by any municipality.