The standards and criteria for size of outdoor advertising authorized to be erected and maintained in zoned or unzoned commercial or industrial areas adjacent to the interstate and primary highway systems are:
(1) The maximum area of any one sign facing any one direction shall be twelve hundred square feet but which in no instance may exceed thirty feet in height and sixty feet in length including border and trim, but not supports or apron; and
(2) The maximum size limitations provided in subdivision (1) of this section apply to each side of a sign structure; and signs placed back-to-back, side-by-side, or in V-type construction with no more than two displays to each facing. Such sign structure shall be considered as one sign.