Lines (Queues)

I think that I'm often pretty decent at finding the line that is going to have me
standing there for the shortest amount of time. I tend to be fairly observant which I think is the key... I don't think any queuing theory that I learned in school is really all that helpful beyond the most elementary rules, which everyone really knows anyway, just not in a formal way.

I've been meaning to write this post since my trip back from the U.K., where I encountered a setup at Heathrow (the security line at terminal 3 for those of you who know the airport) meant to thwart any attempts reason out which path will be quickest. Basically the setup is that there are two lines that approach an enclosure from opposite sides... if you peer in, which I did (it's helpful to be tall) you can see that the lines are symmetric inside, so I went with the line that was shorter on the outside (which, predictably, was the one that was farther away from the origin point for all the people lining up).

Everything was going swimmingly, I was through the checkpoint a good 10 people in front of where I would have been in the other line when I got through the security pre-screening... at which point you are passed on to another set of lines that are not visible from the pre-screening lines. Not only that... but the choice that you made of which pre-screening line to take has now locked you in to which set of security gates you are going through. As it happens, the one that I chose was serviced by only one security gate, while the other line was serviced by two. Not only that, but there was a line to even get to where the security gate line started.

I think that I lost those 10 spots that I had gained, and perhaps even more. The end result was really that I lined up for longer than I wanted to...I was in no danger of missing my flight or anything so catastrophic... but I just wanted to get through the line!

Here are a few rules of thumb that I use to find the quickest line (feel free to suggest some additions!):

1. Two servers are better than one: If there is a line that has two people serving it, it will almost invariably be faster regardless of the length of line. The truth is that people will more often choose the shorter line thinking it will be less time even if the slightly longer line clearly has higher throughput



2. One and a half servers are better than one: Where do you get 1.5 servers? Well, as it happens, often at the airport when you are heading through customs, there will be one line that is for flight crew and disabled people... but there really aren't enough of those special types of people to occupy a whole line, so often when that server has no one in their line, the will take someone from the adjacent line.



3. The line farther from where most of the people come from is often shorter: Chalk this one up to "people are lazy". When people are looking for a line, they often end up in the closest line, not the shortest line... they only look to move lines if the first line is exceedingly long.
   
   
4. Younger usually equals faster: This one is just a rule of thumb, remember. Barring someone in training (which can usually be spotted by a trainer or manager nearby), younger cashiers tend to scan, bag and give change more quickly than someone older.

A few other miscellaneous points: look for new line opportunities (i.e. a new cashier is about to open), if it's available, self-serve is usually fastest and don't get overly agressive... it's just a line.

-kdh