49 U.S.C. § 502 — General authority

(a) The Secretary of Transportation must carry out this chapter. (b) The Secretary may: (1) look into and report on how rail carriers and motor carriers manage their businesses; (2) look into and report on the business of anyone who controls, is controlled by, or shares common control with those carriers, to the extent it relates to that carrier's management; and (3) get whatever information from those carriers and people the Secretary decides is necessary. (c) In applying this chapter to motor carriers, motor carriers of migrant workers, and motor private carriers, the Secretary may: (1) meet and hold joint hearings with state authorities; (2) cooperate with state authorities and use their services, records, and facilities; and (3) make cooperative agreements with a state to enforce state and federal highway-safety laws and regulations related to highway transportation. (d) The Secretary may subpoena witnesses and records related to a proceeding or investigation under this chapter, from anywhere in the United States, to the designated location. If a witness disobeys a subpoena, the Secretary, or a party to the proceeding or investigation, may ask the federal district court for that judicial district to enforce it — and the court may punish disobedience of its order as contempt of court. (e) In a proceeding or investigation, the Secretary may take a witness's testimony by deposition and order the witness to produce records. A party to a proceeding or investigation already at issue on petition and answer may also take a witness's deposition and require the witness to produce records. If a witness won't be deposed or produce records, the Secretary may subpoena the witness to do so. Walking through the deposition rules: a deposition may be taken before a federal judge, a U.S. magistrate judge, a district court clerk, or a state supreme or superior court judge, a city's mayor or chief magistrate, a county court or common-pleas judge, or a notary public who is not a lawyer for, or interested party in, the case. Before taking a deposition, the party (or that party's attorney) proposing to take it must give the opposing party, or that party's attorney of record, reasonable written notice stating the witness's name and the time and place of the deposition. The witness's testimony must be given under oath, must be transcribed, and the transcript must be signed by the witness. If the witness is in a foreign country, the deposition may be taken before an officer or person the Secretary designates, or one the parties agree on in a written stipulation filed with the Secretary, and it must be filed with the Secretary promptly. (f) Every witness summoned before the Secretary, or whose deposition is taken under this section, and the person taking the deposition, are entitled to the same fees and mileage reimbursement paid for similar services in the courts of the United States.