39 C.F.R. § 3020.122 – Hearings.

(a) Initiation. Hearings for the purpose of taking evidence shall be initiated by the issuance of a notice and scheduling order pursuant to § 3020.110.
(b) Presiding officer. All hearings shall be held before the Commission sitting en banc with a duly designated presiding officer.
(c) Entering of appearances. The Commission or the presiding officer before whom the hearing is held will cause to be entered on the record all appearances together with a notation showing on whose behalf each such appearance has been made.
(d) Order of procedure. In requests for advisory opinions before the Commission, the Postal Service shall be the first participant to present its case. Unless otherwise ordered by the Commission, the presiding officer shall direct the order of presentation of all other participants and issue such other procedural orders as may be necessary to assure the orderly and expeditious conclusion of the hearing.
(e) Presentation of the evidence—(1) Presentations by participants. Each participant shall have the right in public hearings to present evidence relevant to the Postal Service's proposal, cross-examine (limited to testimony adverse to the participant conducting the cross-examination), object, move, and argue. The participant's presentation shall be in writing and may be accompanied by a trial brief or legal memoranda. (Legal memoranda on matters at issue will be welcome at any stage of the proceeding.) When objections to the admission or exclusion of evidence before the Commission or the presiding officer are made, the grounds relied upon shall be stated. Formal exceptions to rulings are unnecessary.
(2) Written cross-examination. Written cross-examination will be utilized as a substitute for oral cross-examination whenever possible, particularly to introduce factual or statistical evidence. Designations of written cross-examination shall be served in accordance with part 3010, subpart B, of this chapter no later than three days before the scheduled appearance of a witness. Designations shall identify every item to be offered as evidence, listing the participant who initially posed the discovery request, the witness and/or party to whom the question was addressed (if different from the witness answering), the number of the request and, if more than one answer is provided, the dates of all answers to be included in the record. (For example, “PR-T1-17 to USPS witness Jones, answered by USPS witness Smith (March 1, 1997) as updated (March 21, 1997)”). When a participant designates written cross-examination, two hard copies of the documents (unfastened, single-spaced, not hole-punched) are to be included and shall simultaneously be submitted to the Secretary of the Commission. The Secretary of the Commission shall prepare for the record a packet containing all materials designated for written cross-examination in a format that facilitates review by the witness and counsel. The witness will verify the answers and materials in the packet, and they will be entered into the transcript by the presiding officer. Counsel may object to written cross-examination at that time, and any designated answers or materials ruled objectionable will not be admitted into the record.
(3) Oral cross-examination. Oral cross-examination will be permitted for clarifying written cross-examination and for testing assumptions, conclusions or other opinion evidence. Notices of intent to conduct oral cross-examination shall be filed three or more days before the announced appearance of the witness and shall include specific references to the subject matter to be examined and page references to the relevant direct testimony and exhibits. A participant intending to use complex numerical hypotheticals, or to question using intricate or extensive cross-references, shall provide adequately documented cross-examination exhibits for the record. Copies of these exhibits shall be filed at least two days (including one working day) before the scheduled appearance of the witness. They may be filed online or delivered in hardcopy form to counsel for the witness, at the discretion of the participant. If a participant has obtained permission to receive service of documents in hardcopy form, hardcopy notices of intent to conduct oral cross-examination of witnesses for that participant shall be delivered to counsel for that participant and served three or more working days before the announced appearance of the witness. Cross-examination exhibits shall be delivered to counsel for the witness at least two days (including one working day) before the scheduled appearance of the witness.
(f) Limitations on presentation of the evidence. The taking of evidence shall proceed with all reasonable diligence and dispatch, and to that end, the Commission or the presiding officer may limit appropriately:
1. (1) The number of witnesses to be heard upon any issue;
2. (2) The examination by any participant to specific issues; and
3. (3) The cross-examination of a witness to that required for a full and true disclosure of the facts necessary for exploration of the Postal Service's proposal, disposition of the proceeding, and the avoidance of irrelevant, immaterial, or unduly repetitious testimony.
(g) Motions during hearing. Except as provided in § 3020.105(a), after a hearing has commenced in a proceeding, a request may be made by motion to the presiding officer for any procedural ruling or relief desired. Such motions shall set forth the ruling or relief sought, and state the grounds therefore and statutory or other supporting authority. Motions made during hearings may be stated orally upon the record, except that the presiding officer may require that such motions be reduced to writing and filed separately. Any participant shall have the opportunity to answer or object to such motions at the time and in the manner directed by the presiding officer.
(h) Rulings on motions. The presiding officer is authorized to rule upon any motion not reserved for decision by the Commission in § 3020.105(a). This section shall not preclude a presiding officer from referring any motion made in hearing to the Commission for ultimate determination.
(i) Transcript corrections. Corrections to the transcript of a hearing shall not be requested except to correct a material substantive error in the transcription made at the hearing.
(j) Field hearings. Field hearings will not be held except upon a showing by any participant and determination by the Commission that there is exceptional need or utility for such a hearing which cannot be accomplished by alternative means.