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AS ANY AIR traveler can attest, there’s nothing efficient about airport passenger security screening. The question is: Could it be improved without compromising security? A study from researchers at Virginia Commonwealth University and University of Illinois at Urbana-Champaign suggests one possible approach that might better allocate limited screening resources and spare low-risk passengers from excessive scrutiny.

The study proposes a system under which passengers are separated in real-time when they arrive into two different screening lines based on whether they are deemed to present a higher risk or a lower risk. The former get more scrutiny than the latter.

“Our model determines the optimal threshold for how risky a passenger must be so that sending the passenger to the selectee line is warranted. This is necessary to avoid this situation: If too many low- or medium-risk passengers are put in the selectee line, then the selectee line hits its capacity, and potentially high-risk passengers [who] arrive may be diverted to the nonselectee line,” says study co-author Laura McLay. She adds, “The model determines the optimal amount of room to ‘save’ in the selectee line for risky passengers that may or may not show up later.”

The technique, developed by the researchers, is known as sequential stochastic passenger screening problem (SSPSP). It takes certain aspects of prescreening into consideration—using information the passenger would have provided ahead of time—but does not classify someone as a selectee until assessing the person’s risk level along with the remaining capacity in the selectee screening line. McLay says “the model provides the optimal level of this riskiness factor,” which will determine selectees.

Robert Poole, who is the director for transportation policy at the Reason Foundation, a libertarian think tank, says the approach is a valid one.

“This is the kind of approach I’ve been advocating for years—basically, ever since the initial post-9-11 period. I think it makes really little sense at all to treat all passengers as equally likely to be a threat and to impose huge costs in time and frustration on vast numbers of people every day, because you’re trying to find a needle in a haystack,” he says.

Poole also suggests that more could be done to determine who is low-risk and might, therefore, require less security screening. For example, Poole and others believe that the Registered Traveler (RT) program could assist in this effort. But currently that program relies on identity verification and watch list screening rather than intensive background checks.

The RT program suffered a potentially critical blow earlier this year, however, when Verified Identity Pass, which ran Clear, the largest of the RT operations, was unable to fund the program any longer. That left only three airports with RT lanes. As of press time, it was uncertain whether the remaining RT provider companies would step in and take over Clear’s lanes or whether the three airports would be the only ones where the RT program is continued.

Both Poole and Kevin Mitchell, chairman of the business travel coalition, say that a major reason the Clear program never hit critical mass was that it did not conduct passenger risk assessments. Without a thorough background check, “there was no prospect of the laptop not having to come out, the coat not having to come off, and the shoes not having to come off,” says Mitchell.

The program was originally intended to provide a risk assessment of passengers, notes Mitchell. A provision the House of Representatives included in its version of the Transportation Security Administration Authorization Act calls for TSA and private sector threat assessments to become part of the RT program, as long as the program is integrated into risk-based aviation security and found to expedite checkpoints.

That shows that the House “has recommitted itself to the original intent of the program, which was that it would be a security program,” says Mitchell. He estimates that the entire program will have to be overhauled, and there will likely be a price increase in the services due to background checks. But he says there is demand for it.

Poole criticizes TSA for “refusing to send the fingerprints that Clear collected to the FBI for a criminal history check.” He adds that “a true RT program should check the backgrounds of applicants as thoroughly as is done for airport employees who have unescorted access to the ramp areas. If an FBI criminal history check is good enough to keep airport workers from posing a threat to aircraft, it should be good enough to keep passengers from doing likewise.”

Of course, any system that fast-tracks people through security could pose a danger of allowing someone who doesn’t have a criminal history (but means harm) to take advantage of lighter screening. But Poole and Mitchell note that there’s no such thing as perfect security.

“[W]e don’t want to spend so much of our resources just on passenger screening that we don’t have resources to do other things that are also important for aviation security. So, it’s tradeoffs. And that’s inevitable in this kind of thing—making smart tradeoffs,” says Poole.