25 CFR § 170.228
Can a Tribe use TTP funds to leverage other funds or to pay back loans?
February 24, 2021
(a) A Tribe can use TTP funds to leverage other funds.
(b) A Tribe can use TTP funds to pay back loans or other finance instruments (including those provided through an agreement with another Tribe) that were used for a project that:
(1) The Tribe paid for in advance of the current year using non-TTP funds;
(2) Was included in FHWA-approved TTPTIP; and
(3) Was included in the NTTFI at the time of construction.