This rulemaking would update the Indian Reservation Roads Bridge Program (IRRBP) regulations at 23 CFR 661. These updates will align the regulatory language with the statutory language changes made by section 1119 of MAP-21 and section 1118 of the FAST Act, including changing the name of the program to the Tribal Transportation Program (TTP). This update will also delete the structurally deficient, functionally obsolete, and sufficiency rating language to align the Tribal Transportation Bridge Program terminology for bridge conditions with the terminology used for State DOTs in the Federal-aid Highway Program to provide a consistent means of classifying and referring to bridge condition. Finally, this rulemaking would update the eligibility requirements for bridge rehabilitation or replacement and would provide clarifications to the Tribal Governments when submitting a bridge application.