49 C.F.R. § 370.5 : Transportation — OTHER REGULATIONS RELATING TO TRANSPORTATION — FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION — FEDERAL MOTOR CARRIER SAFETY REGULATIONS — PRINCIPLES AND PRACTICES FOR THE INVESTIGATION AND VOLUNTARY DISPOSITION OF LOSS AND DAMAGE CLAIMS AND PROCESSING SALVAGE — Acknowledgment of claims

(a) Each carrier shall, upon receipt in writing of a proper claim in the manner and form described in the regulations in the past, acknowledge the receipt of such claim in writing to the claimant within 30 days after the date of its receipt by the carrier unless the carrier shall have paid or declined such claim in writing within 30 days of the receipt thereof. The carrier shall indicate in its acknowledgment to the claimant what, if any, additional documentary evidence or other pertinent information may be required by it further to process the claim as its preliminary examination of the claim, as filed, may have revealed.
(b) The carrier shall at the time each claim is received create a separate file and assign thereto a successive claim file number and note that number on all documents filed in support of the claim and all records and correspondence with respect to the claim, including the acknowledgment of receipt. At the time such claim is received the carrier shall cause the date of receipt to be recorded on the face of the claim document, and the date of receipt shall also appear in the carrier's acknowledgment of receipt to the claimant. The carrier shall also cause the claim file number to be noted on the shipping order, if in its possession, and the delivery receipt, if any, covering such shipment, unless the carrier has established an orderly and consistent internal procedure for assuring:
(1) That all information contained in shipping orders, delivery receipts, tally sheets, and all other pertinent records made with respect to the transportation of the shipment on which claim is made, is available for examination upon receipt of a claim;
(2) That all such records and documents (or true and complete reproductions thereof) are in fact examined in the course of the investigation of the claim (and an appropriate record is made that such examination has in fact taken place); and
(3) That such procedures prevent the duplicate or otherwise unlawful payment of claims.

49 C.F.R. § 370.5

83 FR 16223, 6/15/2018