where cost estimates exceed $25,000, to be performed within the United States, except Alaska, without the specific approval in writing of the Secretary of Defense setting forth the reasons therefor. 102. Funds made available in this title for construction shall be available for hire of passenger motor vehicles. 103. Funds made available in this title for construction may be used for advances to the Federal Highway Administration, Department of Transportation, for the construction of access roads as authorized by section 210 of title 23, United States Code, when projects authorized therein are certified as important to the national defense by the Secretary of Defense. 104. None of the funds made available in this title may be used to begin construction of new bases in the United States for which specific appropriations have not been made. 105. None of the funds made available in this title shall be used for purchase of land or land easements in excess of 100 percent of the value as determined by the Army Corps of Engineers or the Naval Facilities Engineering Command, except: (1) where there is a determination of value by a Federal court