The Numbers Guy column in today’s Wall Street Journal relates to our recent post on delays clearing customs at Heathrow (Border Delay Data Leave Fliers Up in the Air, May 5). He hits on a number of points similar to what we brought up. First, demands are going to be very peaked over the day. Check out his graph of arrivals at various US airports:
Note that we have posted about wait times at US ports of entry before. Also note that he is picking on at least two bad airports here with JFK and Miami since they have international flight arriving to multiple terminals. (I am not sure what happens at LAX.) That creates a particular challenge for Customs and Border Protection since they cannot easily move an idle agent from one terminal to another to help out for say 15 minutes or so. This is also an issue at London’s Heathrow.
Another point he mentions (that we touched on) is the difficulty of measuring just what the wait is. Here is the situation in London:
But the two were comparing apples and oranges. Mr. Bryant was citing a different data set that had been leaked to him. Those data came from a Heathrow program to monitor waiting times. Airport monitors counted waiting time by identifying a different passenger each 15 minutes at the very back of the queue, which could be a line formed before passengers split off into separate lines for European passengers, non-European passengers and those prescreened for expedited-entry programs. The clock stopped when the passenger being tracked gets through immigration.
Mr. Green’s figures were based on checks every hour conducted by the U.K.’s Border Force. Its clock started once people had divided into separate queues and stopped when they reached immigration desks. So the U.K. government’s 25-minute and 45-minute waiting-time targets don’t include time to get from the gate to the back of the proper queue, or time spent being checked by an agent.
BAA Airports Ltd., which operates Heathrow, added to the confusion by not disclosing its full set of data initially. On Thursday, it reversed course, publishing the numbers on its website. The results weren’t pretty for Heathrow: Each of its four international terminals were found to breach the 45-minute target for non-European Economic Area passengers last month more than 5% of the time. One in four passengers arriving at Terminal 5 waited longer than 45 minutes.
A final thing — that we didn’t mention but that Laura McLay over at Punk Rock Operations Research did — is that one could think of “pre-loading” agents. That is, putting passengers in short lines in front of agents as they get to the head of the big queue so agent time isn’t wasted with passengers walking over. This clearly gets agents from one passenger to the next faster. However, the Journal notes, it could create issues if one gets caught in the wrong line.
Prof. Blumstein, for example, who waited for over an hour at Heathrow two weeks ago, suggested moving people sooner from the main queue into shorter lines before each desk to “shorten the dead time.” The risk, though, is that the person already at the desk takes longer than average to clear. That can lead to frustration if others who were further behind in the queue get served first.
Or as Richard C. Larson, director of the Massachusetts Institute of Technology’s Center for Engineering Systems Fundamentals who goes by “Dr. Queue” for his studies on waiting in line, puts it, “Welcome to the Olympics! We have for you an Olympic-sized queue delay, along with violation of fair play!”