49 CFR §604.33

1. (a)Notwithstanding any other provision under this part, FTA may initiate its own investigation of any matter within the applicability of this part without having received a complaint. The investigation may include, without limitation, any of the actions described in § 604.32.
2. (b)Following the initiation of an investigation under this section, FTA sends a notice to the entities subject to investigation. The notice will set forth the areas of FTA's concern and the reasons; request a response to the notice within 30 days of the date of service; and inform the respondent that FTA will, in its discretion, invite good faith efforts to resolve the matter.
3. (c)If the matters addressed in the FTA notice are not resolved informally, the Chief Counsel may refer the matter to a Presiding Official.