(a) The following officials, in the order indicated, shall act as Secretary of Transportation, in case of the absence or disability of the Secretary, until the absence or disability ceases, or in the case of a vacancy, until a successor is appointed. Notwithstanding the provisions of this section, the President retains discretion, to the extent permitted by the law, to depart from this order in designating an acting Secretary of Transportation.

(1) Deputy Secretary.

(2) Under Secretary of Transportation for Policy.

(3) General Counsel.

(4) Chief Financial Officer and Assistant Secretary for Budget and Programs.

(5) Assistant Secretary for Transportation Policy.

(6) Assistant Secretary for Governmental Affairs.

(7) Assistant Secretary for Aviation and International Affairs.

(8) Assistant Secretary for Administration.

(9) Administrator of the Federal Highway Administration.

(10) Administrator of the Federal Aviation Administration.

(11) Administrator of the Federal Motor Carrier Safety Administration.

(12) Administrator of the Federal Railroad Administration.

(13) Administrator of the Federal Transit Administration.

(14) Administrator of the Maritime Administration.

(15) Administrator of the Pipeline and Hazardous Materials Safety Administration.

(16) Administrator of the National Highway Traffic Safety Administration.

(17) Administrator of the Research and Innovative Technology Administration.

(18) Administrator of the Saint Lawrence Seaway Development Corporation.

(19) Regional Administrator, Southern Region, Federal Aviation Administration.

(20) Director, Resource Center, Lakewood, Colorado, Federal Highway Administration.

(21) Regional Administrator, Northwest Mountain Region, Federal Aviation Administration.

(b) Without regard to the foregoing, a person directed to perform the duties of the Secretary pursuant to 5 U.S.C. 3347 (the Vacancies Act) shall act as Secretary of Transportation.