1. Bridge numbering: Tribal
Tribally-owned bridges are now required to have bridge inspections conducted and the results submitted to the FHWA for inclusion into the National Bridge Inventory(NBI).
Currently, the NBI allows 15 alpha/numeric characters in a structure #.
Historical BIA numbering: A
For uniformity purposes, the following numbering schema is proposed for Tribally-owned bridges: (Example: Cheyenne River Reservation)
A T ? ? ? ?
[ ] [ ]
[ N T T F I six-code ] [ Tribal schema ]
Only constant in ALL tribal bridges 

2. Bridge numbering: BIA
BIA-owned bridges have been required to have bridge inspections conducted and the results also submitted to the FHWA for inclusion into the National Bridge Inventory(NBI).
A (historical BIA schema)
The following numbering schema will be used for new BIA structures:
A B ? ? ? ?
The following numbering schema will be used for other BIA structures:
A B 8 ? ? ? (Pedestrian bridges)
A B 9 ? ? ? (non-NBI eligible structures)