For the purpose of promoting the public safety, health, welfare, convenience and enjoyment of public travel, to protect the public investment in public highways, and to preserve and enhance the scenic beauty of lands bordering public highways, it is hereby declared to be in the public interest to regulate and restrict the establishment, operation, and maintenance of junkyards in areas adjacent to the interstate and primary highway systems within this state. The legislature hereby finds and declares that junkyards which do not conform to the requirements of this chapter are public nuisances.