of less than 5,000,000 and in which less than 65 percent of National Highway System bridges are classified as in good condition: Provided further , That the Secretary shall distribute funds made available under this heading for a bridge replacement and rehabilitation program to each qualifying State by the proportion that the percentage of National Highway System bridges not classified as in good condition in such qualifying State bears to the sum of the percentages of National Highway System bridges not classified as in good condition in all qualifying States: Provided further , That the funds made available under this heading for a bridge replacement and rehabilitation program shall be used for highway bridge replacement or rehabilitation projects on public roads: Provided further , That for purposes of this heading for the bridge replacement and rehabilitation program, the Secretary shall (1) calculate population based on the latest available data from the decennial census conducted under section 141(a) of title 13, United States Code, and (2) calculate the percentages of bridges not classified as in good condition based on the National Bridge Inventory as of December 31, 2018: Provided further , That funds made available under this heading for construction of the Appalachian Development Highway System shall remain available until expended: Provided further , That a project carried out with funds made available under this heading for construction of the Appalachian Development Highway System shall be carried out in the same manner as a project under section 14501 of title 40, United States Code: Provided further , That subject to the following proviso, funds made available under this heading for construction of the Appalachian Development Highway System shall be apportioned to Appalachian States according to the percentages derived from the 2012 Appalachian Development Highway System Cost-to-Complete Estimate, adopted in Appalachian Regional Commission Resolution Number 736, and confirmed as each Appalachian