9.-(1) The powers conferred by this Law in respect of the erection of hoardings and the display of advertisements shall be exercisable only in the interests of amenity and public safety.
(2) When exercising such powers the Council or the Commissioner or the Improvement Board, as the case may be-
(a) shall, in the interests of amenity, determine the suitability of the site for the erection of hoardings for the display of advertisements under the provisions of this Law in the light of the general characteristics of the locality, particularly the presence therein of any feature of historic, architectural, cultural, scenic or similar interest; and when assessing the general characteristics of a locality the Council or the Commissioner or the Improvement Board, as the case may be, may disregard any advertisements therein already being displayed;
(b) shall, in the interests of public safety, have regard to the safety of persons who may use any road affected or likely to be affected by the erection of any hoarding or the display of any advertisement; and shall in particular consider whether any such hoarding or advertisement is likely-
(i) to obscure or hinder the ready interpretation of any road traffic sign; or
(ii) to obstruct the sight line of any bend, corner or road junction; or
(iii) to take the attention of drivers of vehicles away from a road at any point where special attention is required,
but without prejudice to their powers to have regard to any other material factor.