Public authorities are agencies created by governments to engage directly in the economy for public purposes. They differ from standard agencies in that they operate outside the administrative framework of democratically accountable government. Since they generate their own operating income by charging users for goods and services and borrow for capital expenses based on projections of future revenues, they can avoid the input from voters and the regulations that control public agencies funded by tax revenues.
Institutions built on the public authority model exist at all levels of government and in every state. A few of these enterprises, such as the Tennessee Valley Authority and the Port Authority of New York and New Jersey, are well known. Thousands more toil in relative obscurity, operating toll roads and bridges, airports, transit systems, cargo ports, entertainment venues, sewer and water systems, and even parking garages. Despite their ubiquity, these agencies are not well understood. Many release little information about their internal operations. It is not even possible to say conclusively how many exist, since experts disagree about how to define them, and states do not systematically track them.
One thing we do know about public authorities is that, over the course of the 20th century, these institutions have become a major component of American governance. Immediately following the Second World War, they played a minor role in public finance. But by the early 21st century, borrowing by authorities constituted well over half of all public borrowing at the sub-federal level. This change means that increasingly the leaders of these entities, rather than elected officials, make key decisions about where and how to build public infrastructure and steer economic development in the United States