Identification Signs. Free-standing signs may be erected to identify a shopping center and to list individual occupants, provided that not more than one such sign shall be erected for each 300 feet of frontage on a public street, and further provided that the aggregate area of all sides of any such signs shall not exceed 200 square feet. Such signs may be illuminated, but shall not be of the flashing type, shall not exceed the height of the principal building, shall not be located within 50 feet of a public street or parking area driveway or within 100 feet of the boundary of a residence zone, and shall in no way interfere with the safe functioning of any traffic control signal or directional device.