23 CFR §661.17

1. (a)For bridge replacement or rehabilitation, TTF bridges are required to meet the following:
   1. (1)Must meet the definition of a TTF bridge;
   2. (2)Be classified as a Tribal transportation facility;
   3. (3)Be classified as in poor condition, have low load capacity, or need highway geometric improvements;
   4. (4)Be recorded in the NBI maintained by FHWA;
2. (b)For new bridge construction, TTF bridges are required to meet the following:
   1. (1)Be classified as a Tribal transportation facility;
   2. (2)Be a public bridge that meets the definition of a TTF bridge and recorded in the NBI after project completion.