TSA is responsible for security relating to civil aviation, maritime and all other modes of transportation, including transportation facilities, and is the lead agency for security at airports, ports, and on the nation’s railroads, highways, and public transit systems.

TSA directs Federal security screening operations for passenger air transportation and intelligence information related to transportation security; managing and carrying out program and regulatory activities; discovering, preventing and dealing with threats to transportation security; research and development activities related to enhancing transportation security; coordinating inter-modal transportation security, including aviation, rail, other surface transportation, and maritime transportation; and overseeing most transportation-related responsibilities of the Federal government during a national emergency.