For purposes of this part, the following definitions shall apply:

(a) Junkyard. (1) A Junkyard is 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. This definition includes scrap metal processors, auto-wrecking yards, salvage yards, scrap yards, autorecycling yards, used auto parts yards and temporary storage of automobile bodies and parts awaiting disposal as a normal part of a business operation when the business will continually have like materials located on the premises. The definition includes garbage dumps and sanitary landfills. The definition does not include litter, trash, and other debris scattered along or upon the highway, or temporary operations and outdoor storage of limited duration.

(2) An Automobile Graveyard is an 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. Ten or more such vehicles will constitute an automobile graveyard.

(3) An Illegal Junkyard is one which was established or is maintained in violation of State law.

(4) A Nonconforming Junkyard is one which was lawfully established, but which does not comply with the provisions of State law or State regulations passed at a later date or which later fails to comply with State regulations due to changed conditions. Illegally established junkyards are not nonconforming junkyards.

(b) Junk. Old or scrap metal, rope, rags, batteries, paper, trash, rubber, debris, waste, or junked, dismantled, or wrecked automobiles, or parts thereof.

(c) Main traveled way. The traveled way of a highway on which through traffic is carried. In the case of a divided highway, the traveled way of each of the separated roadways for traffic in opposite directions is a main traveled way. It does not include such facilities as frontage roads, turning roadways, or parking areas.

(d) Industrial zones. Those districts established by zoning authorities as being most appropriate for industry or manufacturing. A zone which simply permits certain industrial activities as an incident to the primary land use designation is not considered to be an industrial zone. The provisions of part 750, subpart G of this chapter relative to Outdoor Advertising Control shall apply insofar as industrial zones are concerned.

(e) Unzoned industrial areas. An area where there is no zoning in effect and which is used primarily for industrial purposes as determined by the State and approved by the FHWA. An unzoned area cannot include areas which may have a rural zoning classification or land uses established by zoning variances or special exceptions.