The primary purpose of bridge inspections is to ensure public safety. The secondary purpose is to preserve the remaining life in our structures through the early detection and addressing of deficiencies.

Federal law governs the requirements of the TxDOT Bridge Inspection Program. The United States Code (23 U.S.C.144) requires that the Transportation Secretary establish and maintain inspection standards for the proper inspection and evaluation of all highway bridges for safety and serviceability. These requirements are spelled out in the Code of Federal Regulations in 23 Highways Part 650, Subpart C, known as the National Bridge Inspection Standards (NBIS). The NBIS describes purpose, applicability, definition of terms, bridge inspection organization responsibilities, qualification of personnel, inspection intervals, inspection procedures, inventory procedures, and supporting references.

On May 6, 2022, the 2022 NBIS Final Rule was published in the Federal Register. Most of the regulations became effective on June 6, 2022, with several provisions becoming effective 24 months after, on June 6, 2024. The full implementation of the regulations and collection of data in accordance with the Specifications for the National Bridge Inventory (SNBI) will require transitional steps and Federal Highway Administration (FHWA) oversight until the full implementation of SNBI data collection in March 2028. TxDOT will utilize the FHWA Transition Tool for transitioning data from the 1995 Coding Guide format to SNBI format and will begin collecting SNBI data for new fields and temporarily coded fields, designated by “T”, beginning January 2024. The SNBI data items will consist of new Item IDs (i.e., Item 58 – Deck will become “B.C.01 – Deck Condition Rating”).

Federal Highway Administration (FHWA) has developed the 23 Metrics for the Oversight of the National Bridge Inspection Program. These metrics are a data-driven, risk-based assessment of the performance of state bridge inspection programs and compliance with the NBIS. Each year, TxDOT's Bridge Inspection Program is reviewed by the FHWA for compliance with these metrics.

TxDOT's Bridge Inspection Program has evolved since the first formal bridge inspection program in Texas began in 1975. Today, data recorded for Texas bridges exceeds that required by the FHWA. A detailed description of the data recorded is contained in the TxDOT Coding Guide. The SNBI supersedes the 1995 Recording and Coding Guide for the Structure Inventory and Appraisal of the Nations Bridges (1995 Coding Guide) and the TxDOT Coding Guide.