Countering terrorism in transportation

Issues in Science and Technology, Summer 2002 by Downey, Mortimer L, Menzies, Thomas R

The curtains of mystery are there now, but not, it appears, as a deliberate strategy. The curtains need to be placed purposefully, and they need to be based on an understanding of what works to deter as well as to protect. An example of what not to do was announcing to the public that air marshals would be present on certain kinds of airplanes and not others, as Congress did in instructing the TSA to give priority to deploying marshals on nonstop, long-distance flights. Such an announcement may be counterproductive to the entire effort to prevent terrorism. Warned off one target because of uncertainty, the terrorist may very well seek another. To prevent such deflection, it is vital that deterrence strategies be thought through carefully and be well placed to protect potential targets that would be most damaging.

It is, of course, important to mix creative deterrence with creative means of intervention. Since September 11, there has been much discussion about "trusted traveler" programs. The idea is that air travelers would confirm their identities through biometric means and volunteer personal information to aviation security authorities in exchange for faster passage through checkpoints. There is a common misperception, however, that this volunteered information would be used primarily to conduct background checks on passengers and thus perhaps prompt the repeated singling out of certain groups of passengers for extra security processing that is burdensome and potentially demeaning. Another possible use for such data, however, is at the more aggregate level to crossmatch the characteristics of all travelers on individual flights, or even across a series of flights scheduled at similar times. For instance, a review of passenger manifests, coupled with other information volunteered by travelers and obtained elsewhere from airline databases, credit bureaus, and public records might reveal that several passengers seated separately on the same flight and with different planned itineraries once shared the same address, traveled together on previous flights, or paid for items using the same credit card. This circumstance might be considered unusual enough to merit closer scrutiny. At a minimum, good data on the characteristics of passenger traffic are crucial for understanding what is normal and thus what is abnormal and possibly suspect. Of course, the many ways in which such data can be used for security purposes can itself create a level of uncertainty that deters terrorists from targeting airlines.

Collaborative security

What is sure to be important in devising security strategies for each mode of transportation is an understanding of the operations and characteristics of the transportation systems themselves. Strategies and tactics developed for one mode of transportation that are modified and applied to another may yield little, if any, benefit. The inspection and screening methods used for airline passengers and baggage in controlled settings, for instance, are ill suited to other kinds of transportation that require more open and convenient access.