The Recording and Coding Guide for the Structure Inventory and Appraisal of the Nation's Bridges (the Guide) has been revised several times in the past. This latest edition revises the Guide to convert all of the units of measurement to the International System of Units (SI). It also provides more thorough and detailed guidance in evaluating and coding specific bridge data. New items have been added to include the reporting of Federal Lands Highway Systems, each State's existing linear reference system, and the methods used to determine the load ratings. Some items in the Guide have also been expanded to provide more definitive and explicit explanations and instructions for coding. Further, more basic definitions applicable to the instructions in the Guide are provided. The changes are based on comments received on the previous Guide and the metric version draft Guide. This revised Guide should be thoroughly reviewed by each individual involved with the National Bridge Inspection Program.