No outdoor advertising shall be erected or maintained beyond 660 feet of the nearest edge of the right of way of the interstate or primary highways in this state outside of urban areas so as to be visible and intended to be read from the main traveled way, except the following:

(1) Directional and other official signs and notices;

(2) Signs advertising the sale or lease of the property upon which they are located;

(3) Signs advertising activities conducted or maintained within 100 feet from the nearest part of the activity as the dimensions of said activity are determined by department regulations, which regulations need not take into consideration the property lines of said activity; and

(4) Directional signs, displays, and devices about goods and services in the specific interest of the traveling public located in a defined area or areas approved by the United States Secretary of Transportation.