(a) Tribes must either:
(1) Use the approved standards referred to in § 170.454; or
(2) Request approval for any other road and highway bridge construction standards that are consistent with or exceed the standards referred to in § 170.454.
(b) For designing and building eligible intermodal projects funded by the TTP, Tribes must use either:
(1) Nationally recognized standards for comparable projects; or
(2) Tribally adopted standards that meet or exceed nationally recognized standards for comparable projects.