‘If you miss your plane or your train, it hardly matters that the queue was a nice place to chill’
I love queues. Not that I love queueing — I may be English but I’m not that English. But from a safe distance, queues are fascinating. They’re less fun if they cause you to miss your flight. In mid-May, two-hour queues for security at Chicago’s Midway airport had just that effect. Jeh Johnson, the US Secretary for Homeland Security, offered travellers some meditative advice: “Contemplate increased wait times as you travel.” I’d hope we can do a little better than mindful meditation.
There are three very different perspectives on queues: psychological, engineering and economic.
The psychological perspective tells us that much of what makes queues unpleasant is nothing to do with the waiting time. If a queue carries risk (you may or may not make your flight), then it is far more stressful. So are queues that are confrontational, unfair or require constant monitoring for queue-jumpers or the sudden opening up of new lines.
A single serpentine queue, secure against cheats, can be a perfectly civilised place to stand and check email or read a paperback. With a bit of cleverness, the queue may be a pleasure — as at well-designed theme parks — or an unobtrusive virtual version, as when you collect a ticket from the supermarket deli counter and do some shopping while waiting for your number.
There are, however, limits to the psychological approach. When the Eyjafjallajökull eruption shut down air travel across Europe in 2010, I found myself queueing for train tickets in Stockholm Central Station, along with almost everyone else in Sweden. Thankfully, the queue had a counter system: simply take a ticket, and wait for your turn. I sat in a café, sipping espresso and typing on a laptop as I waited. But, after a pleasant three-quarters of an hour, I did some mental arithmetic, and realised that the queue was approximately 14 hours long. In the end, if you miss your plane or your train, it hardly matters that the queue itself was a nice place to chill.
When psychology fails, engineering must take the strain. A well-engineered queue copes gracefully with periods of high demand, and balances the cost of waiting against the expense of overproviding idle service staff.
Queue engineers understand that queues can have strange properties. Imagine the queue at a busy post office. During the mid-morning lull, roughly one person a minute arrives and one person a minute can be served. The queue will fluctuate — and, alas, there will never be a negative number of people in the queue — but we can expect it to stay fairly short. Then, during lunch hour, extra people arrive and the queue starts to lengthen — two people, then four, five, 10. As the rush subsides, the capacity of the ticket office again begins to match the inflow of customers: one person arrives each minute, and one person is served each minute.
Annoyingly, even though the inflow and outflow of people from the queue is the same as it was in the morning, the afternoon queue is about 10 people long. It will stay 10 people long until the capacity of the ticket office is greater than the inflow of customers. Once a serious queue has formed, it needs attention or it can linger indefinitely.
That brings us to the economic perspective on queues. Queues are a terrible, inefficient waste of time. If the resource in question is genuinely limited, then the existence of a queue shows that it is being underpriced. If everyone had to pay to join a queue, the queue itself would be shorter, because some people would decide not to bother. Those who did queue would earn back their entry fee in time saved, while the person selling tickets for the queue would make some cash.
In other cases, however, capacity should expand to keep the queue short. Imagine a line so long that most passengers would pay $50 to skip it — probably a good description of the two-hour queues at Midway. Hiring extra Homeland Security staff would save $50 worth of frustration for every extra person they scan from the line.
. . .
How many people could an extra security team see? One per minute, perhaps? Fifty dollars a minute would surely pay for some extra personnel. The problem is that the security team is unlikely actually to receive the $50. In an alternate universe, passengers would have a whip round, hire more agents, and the line would move just fine.
But in the world in which we live, queues remain. Part of the cost is imposed on foreigners, whose annoyance barely registers on the system. (This is particularly true of immigration checks.) For example, on a recent trip from South America to London, I chose to change at Madrid rather than at Miami because I’ve had terrible experiences at Miami. That’s bad for the US economy but security screeners, customs officers and immigration officials respond to political signals, not market ones. The US political system is hardly likely to dance to my tune.
Looking on the bright side, I hear that Reagan National Airport, often used by members of Congress as they fly in and out of Washington DC, works like a charm.
Written for and first published at ft.com.