An industrial park may, subject to the approval of the Sign Committee, have one illuminated or non-illuminated directory sign, not exceeding 70 square feet in area, identifying the name of the industrial park and the names of the industries located therein, at the entrance to or location within the industrial park along a highway or road, but in no event located within or adjacent to a residential area. Such sign shall not be within 10 feet of any street right-of-way line and may be located without the industrial park only upon the property owner's written authorization of same filed with the application.