Michigan Compiled Laws, Chapter 252. Highways § 252.201

(a) “Junk” means old or scrap copper, brass, rope, rags, batteries, paper, trash, rubber debris, waste, or junked, dismantled or wrecked automobiles, or parts of automobiles, iron, steel and other old or scrap ferrous or nonferrous material.

(b) “Automobile graveyard” means any establishment or place of business which is maintained, used or operated for storing, keeping, buying or selling wrecked, scrapped, ruined or dismantled motor vehicles or motor vehicle parts.

(c) “Junkyard” means an establishment or place of business which is maintained, operated or used for storing, keeping, buying or selling junk, or for the maintenance or operation of an automobile graveyard, including garbage dumps and sanitary fills.

(d) “Interstate highway” means a state trunk line highway on the national system of interstate and defense highways, as designated, or as may hereafter be so designated, by the department of state highways and approved by the United States secretary of transportation, pursuant to the provisions of title 23 of the United States code.

(e) “Primary highway” means a state trunk line highway as designated, or as may hereafter be so designated, by the state highway department, and approved by the United States secretary of transportation, pursuant to the provisions of title 23 of the United States code.

(f) “Secondary highway” means a state secondary road or county primary road.