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Congress should set a specific date for the completion of these plans and

hold the Department of Homeland Security and TSA accountable for achiev-
ing them.

The most powerful investments may be for improvements in technologies

with applications across the transportation modes, such as scanning technolo-
gies designed to screen containers that can be transported by plane, ship, truck,
or rail. Though such technologies are becoming available now, widespread
deployment is still years away.

In the meantime, the best protective measures may be to combine improved

methods of identifying and tracking the high-risk containers, operators, and
facilities that require added scrutiny with further efforts to integrate intelligence
analysis, effective procedures for transmitting threat information to transporta-
tion authorities, and vigilance by transportation authorities and the public.

A Layered Security System
No single security measure is foolproof.Accordingly, the TSA must have mul-
tiple layers of security in place to defeat the more plausible and dangerous forms
of attack against public transportation.

· The plan must take into consideration the full array of possible enemy

tactics, such as use of insiders, suicide terrorism, or standoff attack.
Each layer must be effective in its own right. Each must be supported
by other layers that are redundant and coordinated.

· The TSA should be able to identify for Congress the array of poten-

tial terrorist attacks, the layers of security in place, and the reliability
provided by each layer.TSA must develop a plan as described above
to improve weak individual layers and the effectiveness of the layered
systems it deploys.

On 9/11, the 19 hijackers were screened by a computer-assisted screening sys-
tem called CAPPS. More than half were identified for further inspection, which
applied only to their checked luggage.

Under current practices, air carriers enforce government orders to stop cer-

tain known and suspected terrorists from boarding commercial flights and to
apply secondary screening procedures to others.The "no-fly" and "automatic
selectee" lists include only those individuals who the U.S. government believes
pose a direct threat of attacking aviation.

Because air carriers implement the program, concerns about sharing intel-

ligence information with private firms and foreign countries keep the U.S. gov-
ernment from listing all terrorist and terrorist suspects who should be
included. The TSA has planned to take over this function when it deploys a
new screening system to take the place of CAPPS.The deployment of this sys-
tem has been delayed because of claims it may violate civil liberties.

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