49 U.S.C. § 32307 — Investigative powers

(a) General authority. To carry out this chapter, the Secretary of Transportation may (1) inspect and copy any person's records at reasonable times; (2) order a person to file written reports or answer specific questions, including under oath; and (3) hold hearings, put witnesses under oath, take testimony, and require — by subpoena or otherwise — that witnesses appear and testify and that records be produced, whenever the Secretary thinks it's needed. (b) Witness fees and mileage. A witness called under subsection (a) gets paid the same fee and travel mileage that a witness in a U.S. court would get. (c) Civil actions to enforce. To enforce a subpoena or order under subsection (a), a civil suit may be brought in the U.S. district court for the district where the Secretary's proceeding is happening. That court can punish a refusal to obey as contempt of court. (d) Confidentiality of information. Confidential information the Secretary gets under this section — the kind protected by section 1905 of title 18 — can only be shared with another federal officer or employee to help carry out this chapter. This rule does not let anyone withhold that information from a congressional committee that is authorized to have it.