Definitions for "Budget Authority"
Budget authority is that amount the law authorizes the federal government to spend for programs, projects, or activities.
Empowerment by Congress that allows Federal agencies to incur obligations that will result in the outlay of funds. This empowerment is generally in the form of appropriations. However, for most of the highway programs, it is in the form of contract authority.
Congress provides budget authority to federal agencies and programs which allows the agencies (or program administrations) to incur obligations which will result in immediate or future outlays. Budget authority for a fiscal year is like the permission for an agency to enter a contract; it is not the same thing as how much the agency will spend in that fiscal year. That amount is called outlays.