49 CFR § 209.6 - Requests for admission.
(a) A party to any proceeding under subpart B, C, or D of this part may serve upon any other party written requests for the admission of the genuineness of any relevant documents identified within the request, the truth of any relevant matters of fact, and the application of law to the facts as set forth in the request.
(b) Each matter of which an admission is requested shall be deemed to be admitted unless, within 30 days after receipt of the request, the party to whom the request is directed serves upon the party requesting the admission a written answer under oath or objection addressed to the matter, signed by the party.
(c) The sworn answer shall specifically admit or deny the matter or set forth in detail the reasons why the answering party cannot truthfully admit or deny the matter. If an objection is made, the reasons therefor shall be stated.
(d) Any matter admitted under this section is conclusively established unless the presiding official permits withdrawal or amendment of the admission for good cause shown.
(e) Upon motion, the presiding officer may order any party to respond to a request for admission.