49 CFR § 390.15 - Assistance in investigations and special studies.
(a) Each motor carrier and intermodal equipment provider must do the following:
(1) Make all records and information pertaining to an accident available to an authorized representative or special agent of the Federal Motor Carrier Safety Administration, an authorized State or local enforcement agency representative, or authorized third-party representative within such time as the request or investigation may specify.
(2) Give an authorized representative all reasonable assistance in the investigation of any accident, including providing a full, true, and correct response to any question of the inquiry.
(b) Motor carriers must maintain an accident register for 3 years after the date of each accident. Information placed in the accident register must contain at least the following:
(1) A list of accidents as defined at § 390.5 of this chapter containing for each accident:
(i) Date of accident.
(ii) City or town, or most near, where the accident occurred and the State where the accident occurred.
(iii) Driver Name.
(iv) Number of injuries.
(v) Number of fatalities.
(vi) Whether hazardous materials, other than fuel spilled from the fuel tanks of motor vehicle involved in the accident, were released.
(2) Copies of all accident reports required by State or other governmental entities or insurers.