Permitted as a conditional use to be granted by the planning board: advertising signs. The total permitted surface display area of permitted signs shall not exceed the square footage figure produced by application of the following formula (street frontage being expressed here in linear feet): .5 times the total principal street frontage plus 1.0 times the secondary street frontage in the case of a corner lot; but in no case larger than 500 square feet in area. The height shall be not more than .50 times the length of the sign.
Advertising signs shall be limited to the number in existence on February 13, 1973 and may be replaced or relocated in permitted district within one year after the sign is destroyed or removed from the original location.