In the United States, the licensing of prehospital emergency medical providers (emergency medical technicians) (EMTs) and oversight of emergency medical services are governed at the state level. Each state is free to add or subtract levels as each state sees fit. Therefore, due to differing needs and system development paths, the levels, education requirements, and scope of practice of prehospital providers varies from state to state. Even though primary management and regulation of prehospital providers is at the state level, the federal government does have a model scope of practice including minimum skills for EMRs, EMTs, Advanced EMTs and Paramedics set through the National Highway Traffic Safety Administration (NHTSA).