Free Standing Business Signs. One sign for each principal building, provided the total sign area shall not exceed one square foot for each lineal foot of road frontage. Where more than one road frontage exists, additional signs may be placed on such frontage but they shall be computed separately based on the above formula. In no instance shall the total road frontage on more than one road be used to compute the sign area permitted on any single road. Similarly, no one sign regardless of the amount of road frontage shall exceed 200 square feet. No sign shall exceed the building height limit of this zone, nor shall any part of any sign structure, supporting members or sign face be placed closer than 25 feet to any street line, or 50 feet from the point of intersection of any two street lines.