Me. Stat. tit. 23 § 1912
In adopting regulations relating to locations for official business directional signs, the commissioner shall take into consideration such factors as the effect upon highway safety, the convenience of the traveling public and the preservation of scenic beauty. [1981, c. 318, §1(RPR).]
When appropriate, because of the number of signs at one location, the signs shall be displayed in tiers or on panels. Subject to the traffic safety regulations adopted by the commissioner for the purposes of this chapter, the commissioner shall also specify by regulation the general types of locations where such posts, signs or panels may be erected and maintained, and the size, shape, lighting and other characteristics of the panels and posts, including the locations of signs thereon. [1981, c. 318, §1(RPR).]
23 M.R.S. § 1912