The Uniform System of Accounts (USOA) is the basic reference document for the National Transit Database. It contains the accounting structure required by Federal Transit laws (previously Section 15 of the Federal Transit Act). Federal Transit Administration (FTA) implemented minor structural changes to the accounting requirements and reporting system in a Federal Register notice published on October 11, 2016. The changes reflected in that notice will become effective in FY18. This document is the current USOA and should be used for NTD reporting through FY17.