49 CFR 511.55: Final decision on appeal or review.

(a) Upon appeal from or review of an Initial Decision, the Administrator shall consider such parts of the record as are cited or as may be necessary to resolve the issues presented and, in addition, shall, to the extent necessary or desirable, exercise all the powers which he or she could have exercised if he or she had made the Initial Decision.

(b) In rendering his or her decision, the Administrator shall adopt, modify, or set aside the findings, conclusions, and order contained in the Initial Decision, and shall include in his or her Final Decision a statement of the reasons or bases for his or her action. The Administrator shall issue an order reflecting his or her Final Decision.