During a recent flight through a Texas international airport, my experience at its airport security checkpoint exposed a major problem with the Transportation Security Administration (TSA) operations.
When I passed through the PreCheck lane, the line was backed up so that the TSA Officers (TSOs) could not authenticate passenger IDs in a timely manner. The bottleneck was caused by the computed tomography (CT) screening device that was used to screen passenger carry-on bags. The time used to screen such bags was so excessive that the line was grinding to a near stop.
Unfortunately, the situation was worse than first imagined.
Once passing through the magnetometer, the majority of carry-on bags were being pulled aside for secondary (additional) screening. A small sample of carry-on bags that I observed put the percentage selected for secondary screening at around 60 percent.
The likelihood that such a high percentage of bags contained a prohibited item is so small that the problem was either the image that the CT screening device was projecting, or the TSO’s skill set being inadequate to make informed real-time decisions to pull the bag for secondary screening.
The TSA has spent more than $2 billion for these new screening devices. However, there are additional costs of using CT devices for carry-on bags, independent of the direct costs to purchase and maintain them.
The most obvious is that it is slowing checkpoint passenger flow to a point as to congest checkpoints. Any time people congregate in large numbers on the nonsterile side of checkpoints, security risks are elevated.
The secondary screening is also requiring TSOs to resolve every such bag, which most certainly were false alarms. Yet false alarms are expensive. Most importantly, they distract TSOs from what could be more critical risks that may be less obvious to detect.
To justify all such costs requires benefits beyond what the previous X-ray devices provided.
The CT screening devices were justified because they could obtain three-dimensional images of carry-on bags, an improvement over the two-dimensional images provided by X-ray devices. But enhanced functionality alone is insufficient to justify a new technology. The functionality must produce improved performance, as measured by enhanced efficiency or stronger security, or both.
The CT screening devices permit travelers to leave more belongings in their carry-on bags. For those undergoing enhanced screening through standard security lanes, this means less time unpacking their bags. However, if the CT screening devices are slower in processing carry-on bags so that passengers are congregating in the screening area, any such benefits are certainly diminished, and perhaps even completely evaporate.
The situation gets even worse in PreCheck lanes. PreCheck passengers do not need to remove belongings from their carry-on bags. So by adding CT screening devices to these lanes, the TSA has added an unnecessary technology enhancement that does not improve security, while slowing down the processing of passengers, making them less efficient.
The one advantage of CT screening devices is that they can better assess liquids for explosives. As a result, some airports in the UK have relaxed the 100 milliliter liquid requirement.
Explosives pose the biggest threat to the air system. Other prohibited items, like knives and firearms, may cause damage and even result in lives lost. However, such prohibited items pose little risk to destroy an airplane in flight, much like what was experienced on 9/11.
It is reasonable to expect that the relaxation of the 3-1-1 liquid ban is on the TSA’s agenda. The first group that should be eligible to bring larger liquid and gel containers (beyond 3 ounces) are PreCheck vetted passengers. The only benefit that justifies the expense of CT screening devices in PreCheck lanes is that they will be the first group permitted to bring full size tubes of toothpaste, 10-ounce bottles of shampoo and sun block and half-liter bottles of water through security.
Given that there is an autumn lull in air travel until the holiday season, this is the time to sort out the use of CT screening devices. A short-term fix is that every airport with CT screening devices can train a dedicated group of TSOs to man such devices. This will reduce the number of bags that require secondary screening, easing the burden on all TSOs and improving the flow of passengers through checkpoints.
Given the surge in passenger volume during the holiday season, any adjustments that can improve passenger flow while maintaining air system security is a win for all stakeholders. It is conceivable that on some day before the end of 2023, the TSA will screen more than 3 million passengers. Preparing for such extreme numbers is critical to reduce bottlenecks that serve no one’s interests.
The TSA is committed to CT screening devices. They are also committed to biometrics using facial recognition technology to authenticate passenger identity. The former is more accepting by the public, yet provides limited security benefits (unless they impact the liquid limitations). The latter draws suspicion by some, while it provides significant security benefits.
If the TSA wants to maintain and enhance its reputation among the traveling public, it must provide a secure and efficient checkpoint process. Rethinking how CT screening devices are being deployed and used is critical.
Sheldon H. Jacobson, Ph.D., is a professor of Computer Science at the University of Illinois at Urbana-Champaign. He applies his expertise in data-driven risk-based decision-making to evaluate and inform public policy. He has studied aviation security for over 25 years, providing the technical foundations for risk-based security that informed the design of TSA PreCheck.