"The nation's air, land, and marine transportation systems are designed for accessibility and efficiency, two characteristics that make them highly vulnerable to terrorist attack. While hardening the transportation sector from terrorist attack is difficult, measures can be taken to deter terrorists. The dilemma facing Congress is how best to construct and finance a system of deterrence, protection, and response that effectively reduces the possibility and consequences of another terrorist attack without unduly interfering with travel, commerce, and civil liberties. Aviation security has been a major focus of transportation security policy following the terrorist attacks of September 11, 2001. In the aftermath of these attacks, the 107th Congress moved quickly to pass the Aviation and Transportation Security Act (ATSA; P.L. 107-71) creating the Transportation Security Administration (TSA) and mandating a federalized workforce of security screeners to inspect airline passengers and their baggage. […] A leading issue with regard to securing truck, rail, and waterborne cargo is the desire of government authorities to track a given freight shipment at a particular time […]. Debate over who should pay for cargo security, government or industry, and whether mandates or guidelines are the best approach to ensure industry's due diligence in protecting their supply chains are other leading issues. The Port Security Improvement Act of 2006 (P.L. 109-347) will provide grant funds for security improvements to seaports. […] Members of Congress want to know whether current federal policies, regulations, and grants could more effectively promote hazmat transportation security at reasonable costs. […]"
CRS Report for Congress, RL33512