Any junkyard lawfully in existence on April 6, 1967, which is within 1,000 feet of the nearest edge of the right of way and visible from the main traveled way of any public road on the interstate or federal-aid primary system, shall, whenever feasible, be screened by the department so as not to be visible from such public road. Such junkyards may be screened at locations either on the right of way of such public road or on property acquired by the department for that purpose outside such right of way. Whenever the commissioner determines that it is in the best interest of the state, the department may acquire, pursuant to any of the procedures for property acquisition set forth in Article 1 of Chapter 3 of this title, such property or interests therein outside existing public road rights of way as may be necessary to provide adequate screening of such junkyards.