Department of Defense Instruction 1000.27: Mass Transportation Benefit Program (MTBP) [open pdf - 134KB]
"This Instruction: a. Establishes policy, assigns responsibilities, and sets procedural guidance consistent with the authority provided in DoD Directive 5124.02 (Reference (a)) for the administration and management of the MTBP as directed by section 7905 of title 5, United States Code (U.S.C.), and Executive Order 13150 (References (b) and (c)). b. Incorporates and supersedes previous Deputy Secretary of Defense guidance (Reference (d)). This Instruction applies to OSD, the Military Departments, the Office of the Chairman of the Joint Chiefs of Staff and the Joint Staff, the Combatant Commands, the Office of the Inspector General of the Department of Defense (IG DoD), the Defense Agencies, the DoD Field Activities, and all other organizational entities within the Department of Defense (hereafter referred to collectively as the 'DoD Components')."
DoD Directive 1000.27; DoDD 1000.27