(a) An Agency employee engaged in the performance of investigative, advocacy, or prosecutorial functions in a proceeding under § 385.15, § 385.113, § 385.327, § 385.423, § 385.711, § 385.911(e), § 385.913(e), § 385.1009(d), or § 385.1011(d) may not, in that case or a factually-related case, discuss or communicate the facts or issues involved with, or otherwise advise or assist, the Agency decisionmaker or personnel advising the Agency decisionmaker, except as counsel or a witness in a public proceeding, or if the same facts and information are provided to all the parties involved in the matter. The prohibition in this paragraph (a) also includes the staff of those covered by this section.

(b) As used in this section, decisionmaker means the FMCSA official authorized to issue a final decision in the applicable proceeding listed in paragraph (a) of this section.

(c) Nothing in this part shall preclude Agency decisionmakers or anyone advising an Agency decision-maker from taking part in a determination to launch an investigation or issue a complaint, or similar preliminary decision.