Pub. L. 647 as amended, (33 U.S.C. 511-523) commonly referred to as the “Truman-Hobbs Act” provides for the alteration of railroad and highway bridges when found unreasonably obstructive to navigation. Section 6 of that Act establishes policies for the apportionment of such bridge alteration costs. Public Law 89-670, transferred to the Secretary of Transportation from the Secretary of the Army the responsibility for administration of the Act. Pursuant to this responsibility, the Secretary of Transportation has established implementing procedures based on those previously adopted and utilized by the Chief of Engineers prior to 15 October 1966. This regulation adapts these cost apportionment procedures, found in reference § 277.3(c), to Corps of Engineers planning.