School bus shelters for school children where used for or constructed to carry advertising matter, when approved by the superintending school committee of the town in which they are located, and upon payment of applicable license and permit fees may be placed or maintained outside the right-of-way and carry not more than 2 panels each thereon for the identification of sponsors. No such panel shall exceed 32 square feet or extend beyond the sides of such shelter and at least 60 percent of its area must be devoted to public service, safety or other noncommercial use. Each such shelter shall, to the satisfaction of the superintending school committee, be constructed of durable material, with concrete floor raised above ground level, kept clean, well painted or otherwise suitably maintained at all times and kept free from snow, or the commissioner may order its removal.