Monday, September 3, 2012

American queuing 76% better than individual queues

Once the flow of passengers passes a control point (security, passport) which has more than one control position, American Queuing system has clear psychological and physical benefits against individual queues.

  • Passengers is neither stressed by long lines even before he lines up nor does it give the impression of chaos.
  • They will not ask themselves whether they are in the wrong line, because the waiting time is the same for all passengers.
  • The queue will not block because of a "difficult case" which takes longer than usual.
  • The waiting time in the queue is not dependent on the performance of a single counter but depends on the number of occupied counters and on the average processing times.
  • The movement of the waiting passenger accelerates according to the number of available counters, i.e. the waiting time seems shorter for the waiting passengers (the queue moves constantly forward).
  • Individual queues need 76% more waiting area. With large number of passengers, passenger circulation is very limited or even prevented.
Sure there are disadvantage of the American Queuing system: It must be actively managed by 1-2 people in order to ensure optimal throughput at the checkpoint. And, when there are empty queues the posts and tapes interfere with the aesthetics of the waiting area.

1 comment:

  1. Somebody asked about the 76% ... let me try to explain it without having the spreadsheet ready online. Suppose you have a waiting space available which has 12 m width and 15 m length in front of passenger screening. The width indicating the space needed for the number of counters, in this case 5. Those 180 sq m can, however, only cater for 132 m net waiting line (space is lost also in American Queuing (AQ)). If you had 5 lines instead of AQ, this would be 26.4 m waiting line for each queue. The length of 15 m is 76% better than the 26.4 m if there were individual lines.

    Now, you will ask, how come you generalize this? Is it not only applicable for this specific case? In fact, if you increase the length of the waiting space, the calculation and with it the saving of 76% will remain the same. And if you increase the width you based on more counters, it also remains the same. Hope, this helps.