Security: Airport: July 2008 Archives


July 18, 2008

Mobile Edge has rolled out their line of "TSA Compliant" carry-ons. The idea here is that you can open them up for the X-Ray machine and they're easy to scan without requiring you remove your laptop. They're also hideous, as you can see for yourself:

The TSA recently announced plans to implement new security procedures that will allow travelers to pass through security checkpoints without having to remove their laptops from their cases. Simultaneously, the TSA issued a request to laptop bag manufacturers to create "Checkpoint Friendly" laptop bags to help speed up security lines, allowing passengers to get to their departure gates in a timely manner. These new cases will help shorten wait times for more than 250 million passengers that travel annually in the U.S.

The design team at Mobile Edge quickly responded to the TSA request and came up with three new innovative case designs. This new ScanFastâ„¢ Collection consists of a backpack, a briefcase and a messenger bag, all designed to conveniently open for airport screeners and help speed travelers through the X-Ray screening process.

OK, I'm skeptical of this on several levels. First, it's not clear to me that this is going to improve throughput even with constant levels of input. You start in the queue and then move to the tables where you unpack your bags into the bins. The bins and your bags go onto the conveyer belt and get run through the X-ray machine. On the other end, you repack your bags.

There are two ways in which these bags could potentially increase throughput of the system (1) make your bag easier to unpack/pack (2) make all your stuff go through the conveyer faster. It does look to me like these bags could make it easier to unpack/pack your bag, since you don't have to take your laptop out of the bag, just unzip it and flip it open. But this is only a bottleneck (to the extent to which this is a bottleneck) because of insufficient parallelism and pipelining. If you just make the tables longer or have two sets of parallel tables, then people will be able to unpack (and repack) their bags arbitrarily fast. Obviously, this would require some rearrangement of the security area, but it's a lot simpler than introducing entirely new bags.

In my experience, however, the bottleneck is the x-ray machine itself. But it's not clear to me why this would make the x-ray process any faster. Given that the bags open, they presumably take up as much surface area on the belt as the combination of your bag and your laptop, so to the extent to which the linear speed of the scanning process is constant, I don't see why this would make things any faster. Now, it's possible that this allows the scanners to run the belt faster, but given that right now your laptop is on the belt and uncluttered and with this bag it will be partly obscured by the bag, this would presumably make the feed rate required to get an equally thorough scan longer, not shorter.

Given the above, it's not clear to me why these bags would make the screening process faster (or at least that it couldn't be made equally fast with less investment). Even if that somehow were the case, it's not clear that that would make the screening process faster overall; we could easily make the screening process faster by buying more x-ray machines and hiring more screeners, so the current rate reflects some sort of crude cost/benefit analysis. If you could suddenly scan at twice the rate with the same number of screeners, wouldn't you expect the airports to suddenly sharply reduce the number of screeners?