Subject to availability of funding, Tribal transportation facilities must be maintained under either:
(a) A standard accepted by BIA or FHWA (as identified in the official Tribal Transportation Program guide on either the BIA transportation Web site at http://www.bia.gov/WhoWeAre/BIA/OIS/Transportation/index.htm or the Federal Lands Highway - Tribal Transportation Program Web site at http://flh.fhwa.dot.gov/programs/ttp/guide/), or
(b) Another Tribal, Federal, State, or local government maintenance standard negotiated in an ISDEAA road maintenance self-determination contract or self-governance agreement.