Signs only identifying the business, service or products available on the premises, provided that such signs shall not project over the property line; and shall not exceed in total area two times the lineal feet of street frontage of the establishment, not more than 40 square feet per establishment; and shall not project above the top of the parapet or, if a freestanding sign, shall not exceed 35 feet in height; and shall not be placed, maintained, displayed or lighted in such a manner as to hide from view or interfere with the movement of traffic or diminish the effectiveness of any traffic-control device. No flashing signs or rotating beacons shall be permitted.