(a) The junkyard must have been actually in existence at the time the State law or regulations became effective as distinguished from a contemplated use, except where a permit or similar specific State governmental action was granted for the establishment of a junkyard prior to the effective date of the State law or regulations, and the junkyard owner acted in good faith and expended sums in reliance thereon.

(b) There must be existing property rights in the junkyard or junk affected by the State law or regulation. Abandoned junk and junkyards, worthless junk, and the like are not similarly protected.

(c) If the location of a nonconforming junkyard is changed as a result of a right-of-way taking or for any other reason, it ceases to be a nonconforming junkyard, and shall be treated as a new junkyard at a new location.

(d) The nonconforming junkyard must have been lawful on the effective date of the State law or regulations and must continue to be lawfully maintained.

(e) The nonconforming junkyard may continue as long as it is not extended, enlarged, or changed in use. Once a junkyard has been made conforming, the placement of junk so that it may be seen above or beyond a screen, or otherwise becomes visible, shall be treated the same as the establishment of a new junkyard.

(f) The nonconforming junkyard may continue as long as it is not abandoned, destroyed, or voluntarily discontinued. Each State should develop criteria to define these terms.