No permit may be granted for the establishment, maintenance or operation of a junkyard any portion of which is within 1,000 feet of the nearest edge of the right-of-way of an interstate or primary highway, except the following:
1. Those which are screened by natural objects, plantings, fences, or other appropriate aesthetic means, so as not to be visible from the main-traveled way, or otherwise hidden from sight;
2. Those located within areas which are zoned for industrial use under authority of state or local law or ordinance;
3. Those located in areas which, although not zoned by authority of state or local law or ordinance, are actually used for industrial purposes as determined from actual land uses and defined by regulations prescribed by the Director and approved by the Secretary of Transportation; and
4. Those which are not visible from the main-traveled way.