49 U.S.C. § 506: Authority to investigate

The Secretary of Transportation may begin an investigation under this chapter on the initiative of the Secretary or on complaint. If the Secretary finds that a rail carrier, motor carrier, motor carrier of migrant workers, or motor private carrier is violating this chapter, the Secretary shall take appropriate action to compel compliance with this chapter. The Secretary may take action only after giving the carrier notice of the investigation and an opportunity for a proceeding. A person, including a governmental authority, may file with the Secretary a complaint about a violation of this chapter by a carrier referred to in subsection (a) of this section. The complaint must state the facts that are the subject of the violation. The Secretary may dismiss a complaint the Secretary determines does not state reasonable grounds for investigation and action. However, the Secretary may not dismiss a complaint made against a rail carrier because of the absence of direct damage to the complainant. The Secretary shall make a written report of each proceeding involving a rail carrier or motor carrier conducted and furnish a copy to each party to that proceeding. The report shall include the findings, conclusions, and the order of the Secretary. The Secretary may have the reports published for public use. A published report of the Secretary is competent evidence of its contents.