306C.15  Acquisition of signs.
  The department shall acquire by purchase, gift, or condemnation, and shall pay just compensation upon the removal of any of the following advertising devices which are not in conformity with the provisions of this division:
  1.  Advertising devices lawfully in existence on July 1, 1972.
  2.  Advertising devices lawfully in existence on land adjoining any highway made an interstate, freeway primary, or primary highway after July 1, 1972.
  3.  Advertising devices lawfully erected on or after July 1, 1972, but which subsequently become nonconforming.
  4.  Any advertising device erected on the mistaken or negligent advice of any official or employee of the state of Iowa as to the interpretation, effect, or operation of this division, chapter 306B, or rules promulgated by the department.
[C73, 75, 77, 79, 81, §306C.15]