An Administrative Law Judge in the Department of Transportation Office of Hearings will be designated by the Department's Chief Administrative Law Judge to preside at hearings required by statute, or directed to be held under the Administration's discretionary authority in hearings not required by statute, in rotation so far as practicable, unless the Administration shall designate one or more of its officials to serve as presiding officer(s) in hearings required by statute, or member(s) of the staff in proceedings not required by statute.