*Updated: This story was updated with new information from the TSA on March 17, 2011 at 6:41 EDT. *

It might not be long before airport security will let you keep your shoes on, even if they do grope you.

The Transportation Security Administration announced this week that it's accepting proposals for a "shoe scanner" device. It could be a way to cut down on the aggravations of airline travel while still allowing officials to check for weapons and explosives inside a terrorist's Reeboks. The idea crashed and burned when the Department of Homeland Security first proposed it years ago.

The current push to acquire the devices kicks off on April 25, when would-be designers will have the chance to submit proposals for the scanners.

What will the next scanners look like? Will they use X-ray or millimeter wave technology? Will they be held in a TSA agent's hand, or will you have to put your feet on some kind of scanning pedestal? We'll have to wait until the full request is published on April 25. But a TSA spokeswoman, Sarah Horowitz, tells Danger Room that the agency "is not limiting the types of technologies that can be considered, as long as they meet TSA’s requirements, including those for safety and detection standards."

Ever since would-be shoe bomber Richard Reid tried to blow up a transatlantic flight in December of 2001 with explosives concealed in his shoes, TSA has made airline passengers remove their shoes for X-raying, in the belief that terrorists will emulate Reid's failed effort. Nearly 10 years later, TSA's effort still contributes to long lines at security gates.

So, while TSA is still committed to the scanning approach to security, it wants the experience to be more convenient. It's looking to "identify mature shoe scanning technology to support a future procurement which will eliminate the need for passengers to remove their shoes at the checkpoint," says Horowitz.

Why "mature" tech? Because in the past, TSA has been stepped on when trying to scan shoes.

In 2007, TSA tested prototypes of ShoeScanner, built by General Electric's GE Security for $200,000 each. They didn't work. When USA Today took a look at the devices in use, it found that half of the passengers using them still had to take their shoes off, often because they moved their feet during the scanning process. GE submitted a new machine, but problems persisted. So that October, DHS announced it was discontinuing use of ShoeScanner because it did "not meet minimum detection standards" to find weapons and explosives.

In 2008, DHS also contracted with L3 Communications to provide two of its its PassPort explosives trace-detection systems for testing at Los Angeles International Airport. Rather than trying to look into your shoes like a scanning device does, PassPort works by sniffing them for signals of explosives.

L3's website claims PassPort can identify a number of types of explosives, including frequent al-Qaida favorites like Pentaerythritol tetranitrate, or PETN and triacetone triperoxide, or TATP.

(Full disclosure: in 2004, I was a think-tank intern for David Heyman, now the Department of Homeland Security's Assistant Secretary for Policy. And the year before that, I temped for a company that contracted with L3.)

Security expert Bruce Schneier calls this approach "security theater" – implementing measures because they look and feel reassuring rather than providing meaningful security. Al-Qaeda's history is one of disguising explosives in innovative ways.

After 9/11, airlines attempted to prevent another hijacking by hardening cockpit doors and were met with Reid smuggling explosives aboard in his sneakers.

TSA's subsequent shoe-removal policies didn't stop a group of British terrorists from developing liquid explosives to smuggle on board inside sports drink bottles. The liquids ban that was put in force was no obstacle to Umar Farouk Abdulmutallab's attempt aboard Northwest Airlines Flight 253 to detonate a bomb that he concealed in his underpants.

The shoe-removal policy and bans on liquids elicited some grumbling from the public, but nothing like the public outrage at TSA's solution to future underwear bombers, when naked scanners, rolled out last fall.

"Of course it's not going to make anyone safer," Schneier e-mails Danger Room about the shoe scanners, "but it will make the security theater go faster, and that's a good thing." We could all stand a little less undressing at airports these days.

But don't let a marginally faster airport experience lull you into complacency. Shoe-scanning might get you through the security line quicker – assuming the scanner gizmo DHS wants actually works this time. But that doesn't mean it'll stop the next airborne terrorist.

Photo: TSA

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