shall be transferred to the Appalachian Regional Commission in accordance with section 104(a) of title 23, United States Code. Federal-aid highways (limitation on obligations) (highway trust fund) Funds available for the implementation or execution of Federal-aid highway and highway safety construction programs authorized under titles 23 and 49, United States Code, and the provisions of the Fixing America's Surface Transportation Act ( Public Law 114–94 ), or any successor surface transportation reauthorization Act authorizing appropriations for fiscal year 2021, shall not exceed total obligations of $61,130,000,000 (increased by $1,000,000) (reduced by $1,000,000) for fiscal year 2021: Provided , That the Secretary may collect and spend fees, as authorized by title 23, United States Code, to cover the costs of services of expert firms, including counsel, in the field of municipal and project finance to assist in the underwriting and servicing of Federal credit instruments and all or a portion of the costs to the Federal Government of servicing such credit instruments: Provided further , That such fees are available until expended to pay for such costs: Provided further , That such fees are in addition to administrative expenses that are also available for such purpose, and are not subject to any obligation limitation or the limitation on administrative expenses under section 608 of title 23, United States Code: Provided further , That for amounts subject to the obligation limitation under this heading during fiscal year 2021, the Federal share of activities undertaken pursuant to chapters 1 or 2 of title 23, United States Code shall be, at the option of the State, District of Columbia, territory, Puerto Rico, or Indian Tribe, as applicable, up to 100 percent: Provided further , That the preceding proviso does not apply to programs authorized under sections 115 and 117 of title 23, United States Code. (liquidation of contract authorization) (highway trust fund) For the payment of obligations incurred in carrying