The Hidden Costs of Extra Airport Security

I recognize that the outcry over the T.S.A.’s new security procedures — which has been both broad and deep in technology, travel and political blogs, but which has been less acute elsewhere in the country — has a bit of a Brooks Brothers Riot quality to it. That is because its effects are felt most manifestly among those relatively few Americans who have the means to travel (and the wherewithal to write about it).

It is, moreover, a hard story for the media to resist, given the sexy sorts of issues (Terrorism! Privacy! Civil Liberties! Junk-Touching!) that the debate turns upon.

Nevertheless, this is more than just some sort of wedge issue for yuppies with wanderlust: there are real and quite tangible consequences stemming from the procedures that the T.S.A. chooses to implement.

Consider what happens, for instance, when travelers are inconvenienced by a new security procedure. Yes, most of them will simply pass through the new body-scanners without incident, buy a snack at the Cinnabon, and go on their merry way. But others will do something different: they will be sufficiently annoyed by the procedures that they will decide not to travel by air the next time they have the choice.

In the past, more cumbersome security procedures have had deleterious effects on passenger demand. A study by three professors at Cornell University found, for instance, that when the T.S.A. began to require checked baggage to be screened in late 2002, it reduced overall passenger traffic by about 6 percent. (You can actually see these effects a bit when looking at the air traffic statistics: passenger traffic on U.S.-based airlines dropped by about 6 percent from the fourth quarter of 2002 to the first quarter of 2003 — greater than the usual seasonal variance — even though the economy was recovering and travelers were starting to get over the fear brought on by the Sept. 11 attacks.)

More stringent security procedures, in essence, function as a tax upon air travel, and produce a corresponding deadweight loss. Teleconferences are often a poor substitute for person-to-person interaction, and when people are reluctant to travel, some business deals don’t get done that otherwise would have. Recreational travelers, meanwhile, may skip out on vacations that otherwise would have brought them pleasure and stress-relief (while improving revenues for tourism-dependent economies). The tenuous profits of the airline industry are also affected, of course. Revenue losses from the new bag-checking procedures may have measured in the billions, according to the Cornell study.

Other passengers may substitute car travel for air travel. But this too has its consequences, since car travel is much more dangerous than air travel over all. According to the Cornell study, roughly 130 inconvenienced travelers died every three months as a result of additional traffic fatalities brought on by substituting ground transit for air transit. That’s the equivalent of four fully-loaded Boeing 737s crashing each year.

The effects could run in the opposite direction, of course, if new security procedures made passengers feel more secure about air travel — and therefore more willing to fly. As Anil Dash points out, even if one takes the cynical view that full-body scans are a type of “security theater”, and have little tangible effect on deterring terrorism, the mere act of making travelers feel safer may in and of itself be beneficial.

The Cornell data suggest, however, that travelers may tell pollsters one thing, and behave in a different way. Polls in 2002 and 2003 found that most people thought the new procedures were indeed making air travel safer — just as most people now say they favor the full-body scans. Despite this, there was a material reduction in air travel: inconvenience outweighed security for quite a few passengers when push came to shove.

The new full-body scans could have similar effects. In addition to making some travelers feel as though their privacy has been compromised, they require more time per traveler than traditional metal detectors to do, which could have unpredictable effects at check-in points that are already stretched to capacity at many airports. At the home airports that I’ve traveled out of for the last several years — the three major airports in New York and the two in Chicago — the T.S.A. really seemed to have gotten the hang of the “old” procedures, processing the security lines efficiently and usually getting everyone through after just a few minutes of waiting. (Although I wouldn’t recommend this behavior, I’ve fairly often arrived at the airport no more than 30-50 minutes in advance of a domestic flight, and have missed just one flight in the past ten years.) Now, that balance may be upset.

Finally, one should consider the implicit message that the full-body scans conveys to travelers. The explicit message is that the T.S.A. is doing everything in its power to keep us safe — something which might increase confidence in air travel. Many travelers, however, might read between the lines in the following way: the T.S.A. is making us go through all this rigmarole because otherwise air travel would be very, very dangerous; terrorists might be hiding explosives in their underpants! (Among other places.) One can draw an analogy, for instance, to the new security cameras that the city of Chicago has been installing: they are deliberately designed to be conspicuous, since the cameras are accompanied by extremely vibrant blue police lights — and they may well decrease crime. But they only appear in marginal neighborhoods that were susceptible to high crime rates to begin with. The explicit message is that the Chicago Police Department is doing what it can to keep everyone safe. The implicit message is that it is doing so because this is a really dangerous neighborhood — and perhaps you should be buying your condo, or planning your wedding reception, somewhere else.

How the new security procedures affect demand for air travel overall is hard to gauge. And of course, if they indeed prevent another terrorist attack, the upside would be quite significant, since few events would do more to reduce air travel than another 9/11.

But there is an argument that the T.S.A. deliberately ought to be instituting the new procedures slowly and selectively in order to provide for a sort of natural experiment. It is one thing to cite the polls, which indeed show most Americans in favor of full-body scans. But if, for instance, Chicago O’Hare installs new machines and Chicago Midway does not, and passenger traffic at O’Hare drops by 9 percent while traffic at Midway holds steady, that would provide considerably more tangible evidence of how travelers are reacting to the new protocols than polls ever could.