The End Of Long Airport Security Lines?

Duke University researchers believe they’ve found ways to screen luggage and people quickly and safely, even in the face of evolving security risks.

It’s easy to lose perspective when it comes to air travel. “Everybody on every plane should just constantly be going wow!” Louis CK said in his famous “miracle of flight” rant. “You’re sitting in a chair in the sky.” What’s upsetting even to those of us who appreciate this wisdom is just how easy it is to lose perspective in an airport–and no place erodes our patience faster than the security line.


Airport security will always be a tricky balance between speed and assurance. Every air traveler demands complete safety, which means zero-give-or-take-zero security mistakes, which means a cautious screening approach, which means long lines and potential missed flights, which means temporarily forgetting demands about safety. There’s a loop of frustration here that’s hard to avoid.

That doesn’t mean the pain is beyond relief. With funding from the Department of Homeland Security, some Duke University researchers believe they’ve found ways to expedite the security process using new optical technology. These advances could help officials screen luggage and people quickly and safely, even in the face of evolving risks.

“Right now the fact that resolving any of these threats involves a lot of time and manpower leads to not only slower lines but also a lot of extra expense,” Joel Greenberg of Duke’s Imaging and Spectroscopy Program tells Co.Design. “Boiled down, our goal is to increase the detection capabilities and decrease the false-alarm rates so that everybody’s happier in the end.”

Greenberg’s work focuses on creating a new generation of luggage scanners. Right now most airport luggage machines measure “transmitted” X-rays–meaning some X-rays go straight through an object but others are absorbed or scattered by it. If a knife goes through the scanner, for instance, the blade absorbs or scatters the rays, leaving a shadow in that shape for security agents to spot.


That’s great for knives and other weapons with distinct configurations. It’s not nearly as effective for detecting more advanced threats, especially liquid explosives. (As Greenberg puts it, current scanners can’t distinguish toothpaste from C-4.) That limitation has a direct impact on air travelers: large volumes of liquid can’t be taken through the security line, and small volumes must be unpacked and placed in separate three-ounce bags to minimize the threat.

The machines being designed at Duke not only measure the X-ray transmission but also measure the X-ray scatter. That scatter signal provides molecular, energy-sensitive information about the object in question–including a variety of liquids. Any older machines capable of processing these scatter signals would have needed hours to do so; the latest technology does the job in real time, boosted by a technique called “compressed sensing,” which enables parallel measurements to occur at once.

“So the upshot is, we think that we can translate scatter imaging, which has this wealth of new information that allows you to learn so much more about your object, into a practical technology,” says Greenberg. “Whereas people have been trying to do that for the last couple decades and have not really been successful.”

This test object scanner, created at Duke, is capable of processing scattered X-ray signals as well as typical transmitted signals. Courtesy of the Duke Imaging and Spectroscopy Program.

Success, in this case, might translate into a security line that’s faster for travelers and cheaper for security officials and safer for all. On the front end, the researchers envision a process by which people place their entire bag on the scanning belt–liquids, laptops, etc.–without pausing to remove certain items. On the back end, agents would see the traditional image transmission plus perhaps a threat indicator that alerted them (via colored flags) of potentially harmful liquid substances.

“From a real technological point of view, we’re going to go just as fast, but we’re going to learn a thousand times more information,” Greenberg says.


Of course, the airport security experience is about more than scanning luggage. The fundamental insights at the heart of this research will help screen passengers, too. Other Duke researchers are building imaging systems that scan bodies in motion–a model that could replace the current millimeter wave scanners that require travelers to stand still as the lens rotates and records information. In the extreme ideal scenario, passengers might even be able to walk straight to a gate through a corridor that scanned them for threats.

The question on every traveler’s mind is: when. A few North Carolina Congressmen got a sneak peek at the technology earlier this month, and Greenberg says Homeland Security officials will get to see a prototype in action early next year. If all goes well, there should be a flurry of industry activity in the next year or two to get things off the ground (in a manner of speaking).

Put another way, we might only be a few years away from being able to complain about the miracle of speedy security. Can’t wait.


About the author

Eric Jaffe is an editor at CityLab, where he writes about transportation, history, and behavioral science, among other topics, through the lens of urban life. He's also the author of The King's Best Highway (2010) and A Curious Madness (2014)