49 CFR 5.73: Avoiding bias.

Consistent with all applicable laws and ethical standards relating to recusals and disqualifications, no Federal employee or contractor may participate in a DOT enforcement action in any capacity, including as ALJ, adjudication counsel, adversarial personnel, or decisional personnel, if that person has:

(a) A financial or other personal interest that would be affected by the outcome of the enforcement action;

(b) Personal animus against a party to the action or against a group to which a party belongs;

(c) Prejudgment of the adjudicative facts at issue in the proceeding; or

(d) Any other prohibited conflict of interest.