Bigger isn’t always better when it comes to airport security

Opinion>Opinions - National Security The views expressed by contributors are their own and not the view of The Hill Bigger isn’t always better when it comes to airport security Comments: by Sheldon H. Jacobson, opinion contributor - 08/06/26 9:00 AM ET Comments: Link copied by Sheldon H. Jacobson, opinion contributor - 08/06/26 9:00 AM ET Comments: Link copied

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The Transportation Security Administration is moving to a full-scale deployment of computed tomography scanning equipment at airport security checkpoints. These devices provide a three-dimensional image of the content of carry-on bags, as opposed to the two-dimensional image that the previous X-ray machines provided. That means that taking items out of carry-on bags is unnecessary when scanned using this new technology.

Though the new scanners can identify threat items that older X-ray machines may have missed, such as liquid explosives, subjecting all passenger carry-on bags to this technology is misguided.

The TSA relies on a layered system to keep the air system secure. Though any one layer may be compromised, the collective security of the system relies on multiple layers to keep bad actors from inflicting harm. The overriding principle that permeates TSA operations is risk-based security, which allocates security resources commensurate with security risk — i.e., more security attention should be directed to passengers and baggage that carry greater risk.

TSA Precheck is the poster child for risk-based security. When people voluntarily provide background information, this information reduces their risk to the air system. Thus, they are given access to PreCheck airport screening lanes that provide expedited screening through security checkpoints. For those who opt in, TSA PreCheck Touchless ID lines move even faster. The tradeoff between giving up some personal privacy in exchange for expedited screening is one that many travelers welcome, making air travel more palatable for travelers and more efficient for TSA officers.

Computed tomography scanning equipment is significantly more expensive — as much as $800,000 per machine — than two-dimensional X-ray machines, which run as much as $65,000 per machine. Given that PreCheck vetted passengers are physically screened with walk-through metal detectors as opposed to millimeter wave advanced imaging technologies, which also carry a significant cost differential, this invites the question: Can PreCheck vetted passengers have their carry-on bags be subjected to two-dimensional X-ray machines versus the new scanners without sacrificing security? If the answer is yes, then using computed tomography scanners for PreCheck vetted passenger carry-on bags is over-screening, the antithesis of risk-based security.

Over-screening is like using a machete to open a peanut shell. It will do the job, but it is more than what is needed. Because the new scanners are more expensive than X-ray machines, using them when they provide no added security benefit is a waste of taxpayer dollars. In an environment where there are limited resources, reserving computed tomography scanners for passengers for whom the TSA knows the least about (non-PreCheck vetted passengers) is a more effective strategy.

Computed tomography scanning equipment also operates more slowly than X-ray machines, causing checkpoint bottlenecks as passengers wait for their carry-on bags to be screened. If the new scanners flag a bag for additional screening, this bottleneck becomes even more pronounced. Given that the administration has been focused on reducing government waste, using the new scanning equipment where it offers no benefit makes no sense.

One possible explanation for deploying these new scanners at all checkpoint lanes is in preparation to end the liquid, aerosol and gel rule, which most travelers would welcome. Yet until the leadership vacuum at the TSA is resolved — there is currently no Senate-approved administrator — and adequate evaluation is conducted, including TSA Red Team testing, this would be premature.

So what is the best use for computed tomography scanners?

The appropriate strategy is to deploy them at standard checkpoint screening lanes and leave the 2-D X-ray equipment at PreCheck lanes. Then the money saved can be used to encourage more people to enroll in Trusted Traveler programs like PreCheck so they too would be eligible to be screened in expedited lanes. This could include offering PreCheck at no cost to anyone willing to enroll in the program.

If the number of PreCheck eligible travelers screened could reach 70 percent, airport security checkpoint could offer more PreCheck lanes to ensure that the time spent at airport security checkpoints remains low. The cost savings in terms of equipment (walk-through metal detectors versus advanced imaging technologies) and personnel to staff the checkpoints would be significant. Moreover, proper risk-based allocation of resources would make the air system more secure, which is why the TSA exists: for the benefit of all travelers.

Without doubt, the new screening equipment has its place at airport security checkpoints. At this time, they do not belong at PreCheck security lanes.

Sheldon H. Jacobson, Ph.D., is a professor of computer science in the Grainger College of Engineering at the University of Illinois Urbana-Champaign. He has researched risk-based aviation security for over 30 years, contributing to the design of TSA PreCheck.

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