49 CFR §389.25

The Administrator may initiate any further rulemaking proceedings that he/she finds necessary or desirable. For example, interested persons may be invited to make oral arguments, to participate in conferences between the Administrator or his/her representative at which minutes of the conference are kept, to appear at informal hearings presided over by officials designated by the Administrator at which a transcript or minutes are kept, or to participate in any other proceeding to assure informed administrative action and to protect the public interest.