In late 2001, Congress passed the Aviation and Transportation Security Act of 2001 (ATSA). Among other things, the ATSA created the Transportation Security Administration (TSA) as an agency within the Department of Transportation (DOT). Passage of the Homeland Security Act of 2002 one year later created the Department of Homeland Security (DHS) and transferred TSA to its authority in an attempt to centralize and streamline interactions between agencies involved in critical infrastructure protection.
In 2007, Congress passed the Implementing Recommendations of the 9/11 Commission Act (9/11 Commission Act), which implements many of the recommendations made by the 9/11 Commission following the September 11, 2001 attacks. Among other things, the 9/11 Commission Act directed national strategies for public transportation and rail security.