49 CFR § 554.7 - Investigation priorities.
(a) Compliance investigation priorities are reviewed annually and are set according to the following criteria:
(1) Prior compliance test data;
(2) Accident data;
(3) Engineering analysis of vehicle and equipment designs;
(4) Consumer complaints; and
(5) Market share.
(b) Defects inputs are reviewed periodically by an appropriate panel of engineers in consultation with the Office of Chief Counsel to determine whether a formal investigation should be opened by the Office of Defects Investigation.