This part shall apply in any county having a population of more than three hundred thousand (300,000), according to the 1980 federal census or any subsequent federal census, and shall be inapplicable to such residential structures within the right-of-way of projects administered by the department of transportation whenever a determination has been made that such structures are of historical significance and plans for their disposition or preservation have been coordinated with and concurred in by the state historic preservation officer of the Tennessee historical commission.