49 C.F.R. § 1.21
(b) The delegations of authority in subpart C (Office of the Inspector General) and subpart D (Operating Administrations) of this part do not extend to the following actions, authority for which is reserved to the Secretary or the Secretary's delegatee within the Office of the Secretary:
(1) General transportation matters.
(2) Legislation, rulemakings, and reports.
(3) Budget and finance.
(4) Personnel.
(iv) Approval of the following actions relating to Schedules A, B, C, or D (5 CFR part 213) and noncareer executive assignment positions or incumbents, except for actions under Schedules A and B limited to one year or less at grade GS-9 or lower, or an equivalent level:
(5) Security.