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How long is the security line at Dulles?

Dulles Airport built two huge security checkpoints in 2009, but somehow it still can take a very long time to get through security, especially at busy times when a lot of international flights are soon to leave. How long does it really take? Now we have some data.


Photo by steve buttry on Flickr.

Last August, Dulles installed new systems that estimate the wait time at each checkpoint. Cameras connect to computers which try to judge the wait based on the size of the line and the rate of people clearing the checkpoint. You can view the wait times on the web or a smartphone, and screens at the airport show the estimated times so travelers can pick the shorter line.

I set up a system to automatically capture the wait times every 5 minutes, beginning September 23. It's been running for a little over 6 months now, which gives us a good set of data to analyze.

The west checkpoint is the one on the right when you're facing the terminal. It's closer to Daily Garage 2, and also the exit from customs, and is near the first stop on the shuttle buses. Here are the wait times across the average weekday:


Average wait at the west checkpoint for each 5-minute segment, weekdays.

There are some peaks at busy times of day, like early morning, just before noon, and especially late afternoon (when all of the flights to Europe leave), but it's fairly consistent.

The east checkpoint, however, has far more variation:


Average wait at the east checkpoint for each 5-minute segment, weekdays.

Here, the wait times are very low except right around the peak times. This camera seems to report a minimum time of 2 minutes; even in the middle of the night, when the checkpoint is closed, it shows 2 minutes.

Any ideas why this one varies more? Is the volume of people checking in at United or other counters on that side more uneven than on the airlines with west side counters or passengers re-entering after clearing customs? Does TSA staffing vary more? Does the fact that shuttles drop people off first at the west side drive more, and more even, demand to that side?

What about weekends?

Those are weekdays. Are weekends different? Regional transportation always shows huge differences between weekdays and weekends, like Capital Bikeshare usage data, but airlines run pretty much the same schedule 7 days a week. And, in fact, the pattern is little different except the average wait time is slightly less on weekends:


Average wait at the west checkpoint for each 5-minute segment, weekends.


Average wait at the west checkpoint for each 5-minute segment, weekends.

Which checkpoint is better?

Which checkpoint should you take? The best strategy is to actually look at the monitors, but most likely it will tell you to head east unless it's a peak time, when its lines get long:


Probability the east checkpoint has a longer wait for each 5-minute segment, 4 am-10 pm.
Shaded areas show times the probability exceeds 50%.

How big are the differences? If one is better, is that a strong difference? Especially with the real-time screens, you'd expect a lot of travelers to move toward the checkpoint with the shorter line, but apparently not enough do to keep the two balanced.


Differences in waits between the east checkpoint and west checkpoint per 5-minute segment.

This graph shows the size of the typical differences between the two. The center line is the median difference, and the darker area the middle 50% of times; as in the above chart, east usually has the longer lines during these peaks while west is worse at other times.

Still, there is plenty of time when the difference between the two is quite significant, assuming the equipment is accurate. If you have to fly through Dulles, a perfect symbol of how our nation once built great public works but now barely bothers to keep them up and makes new improvements on the cheap, you'll already have long drives and walks to get to your gate; you might as well minimize the wait in those interminable security lines.

David Alpert is the Founder and Editor-in-Chief of Greater Greater Washington and Greater Greater Education. He worked as a Product Manager for Google for six years and has lived in the Boston, San Francisco, and New York metro areas in addition to Washington, DC. He loves the area which is, in many ways, greater than those others, and wants to see it become even greater. 

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Dulles Airport built two huge security checkpoints in 2009, but somehow it still can take a very long time to get through security, especially at busy times when a lot of international flights are soon to leave.

The answer to 'somehow' should be pretty obvious - they need more staff to man the X-ray machines.

They built the massive security mezzanines, but many of the inspection lines are not staffed - that's where the chokepoint is.

Based on the data, it's easy to see why they are not staffed. The peaking problem is hard for transit, since the single biggest cost is labor and the standard labor shifts do not nicely align with peak hours. You have the same challenge with the peaks in the security lines - if you add enough staff to handle the peaks with ease, then they're spending a lot of time between the peaks just standing around.

by Alex B. on Apr 9, 2013 10:19 am • linkreport

A bit off topic:

http://www.theatlantic.com/national/archive/2013/04/american-infrastructure-watch-two-china-based-reports/274802/

I'm guessing you pulled the data from the wait line? Do we know if that is good data?

by charlie on Apr 9, 2013 10:26 am • linkreport

Agree re: the airport security staffing issue. I once spoke with a TSA agent coming off duty and he said that (pre-sequester) the biggest issue for them is no-shows and generous sick leave among screeners. Not surprising for a high-stress, repetitive job.

Then again, the security line estimation screen this last Friday said we could expect a 26 minute wait, and we were able to cruise through in less than 15. Seems like all parties have some work to do.

by Mark L. on Apr 9, 2013 10:37 am • linkreport

I make it a point never to fly out of Dulles when it can be avoided but the wait times at National first thing in the morning like 6-7 AM are often pretty awful. Of course nothing rivals JFK.

by Alan B. on Apr 9, 2013 10:44 am • linkreport

Really cool data but this statement is unnecessary and inaccurate:

If you have to fly through Dulles, a perfect symbol of how our nation once built great public works but now barely bothers to keep them up and makes new improvements on the cheap

Dulles just built a $1.4B aerotrain system and a huge new security area, building enough capacity for many years to come. Not to mention, the Silver Line which provides a transit option to get to the airport and the Outer Beltway which will provide a new highway option. Although it's true that we don't invest sufficiently in infrastructure, Dulles does *not* symbolize that...in fact, it's much closer to symbolizing what the rest of the country should strive for.

by Falls Church on Apr 9, 2013 10:59 am • linkreport

Could similar techniques let you evaluate e.g. WMATA wait times/headways for rush hour, mid-day, latenight, by scraping their published PIDS predictions?

http://www.wmata.com/rider_tools/pids/showpid.cfm?station_id=1

by BO on Apr 9, 2013 11:29 am • linkreport

Unfortunately, the route for the aerotrain is somewhat inefficient: (1) It does not stop at Terminal D; (2) The Terminal C stop is not at Terminal C, but past Terminal C at the site of a "future terminal," meaning that passengers from C have to walk a substantial distance in the wrong direction to get on the plane. For $1.4 billion, you'd think that we could build a train would stop at sensible places in all the terminals.

by Andrew S. on Apr 9, 2013 11:36 am • linkreport

For $1.4 billion, you'd think that we could build a train would stop at sensible places in all the terminals.

Why? So when they do replace the C/D concourse, people can complain then about a) the long walk to the new concourse, b) the expense involved in building a new station in a different spot (why didn't you do it right the first time!), or c) all of the above?

Good thing MWAA realized the 'damned if you do, damned if you don't' trap you've laid out.

by Alex B. on Apr 9, 2013 11:45 am • linkreport

"Dulles just built a $1.4B aerotrain system and a huge new security area, building enough capacity for many years to come. Not to mention, the Silver Line which provides a transit option to get to the airport and the Outer Beltway which will provide a new highway option. Although it's true that we don't invest sufficiently in infrastructure, Dulles does *not* symbolize that...in fact, it's much closer to symbolizing what the rest of the country should strive for."

Have you ever been in the C/D concourse at Dulles? It is a national embarrassment, the place was built as a "temporary" terminal in the early Reagan administration and I would be very surprised if it were replaced in the next 10 years.

by Phil on Apr 9, 2013 11:52 am • linkreport

The issue with the Aerotrain station is not the Aerotrain planning, but rather the lack of planning and, more important, funding for an actual Terminal C/D in the planned location instead of the garbage "temporary" terminal that is currently there.

I have to think that United's merger with Continental didn't help move that project forward.

by ah on Apr 9, 2013 12:04 pm • linkreport

My understanding is that the designs for the replacement terminal at Dulles are complete but that the project didn't move forward because the economy tanked just around the time it was supposed to start. I do know for sure that the new control tower is designed to integrate with the terminal when it's eventually constructed. Also the AeroTrain will have stops on both ends (the C terminal is already in use) and eventually form a loop for a future ticketing area to the south. They've done a pretty good job overall with their master plan if you ask me.

by Craig on Apr 9, 2013 12:07 pm • linkreport

But if the wait times are reduced, there will just be more passengers. Induced demand you see.

by Chris S. on Apr 9, 2013 12:13 pm • linkreport

Craig - sorry for loose use of the word "planning". They have a design, but not anything close to actual architectural drawings, contracts, bids, etc. It's just conceptual, other than the location.

Here are some pics of the concept.

http://www.kpf.com/project.asp?R=1&ID=60

by ah on Apr 9, 2013 12:18 pm • linkreport

I don't understand the graphs. Why does each time on the x-axis look like it has four observations, one for each color, on the y-axis? Should each time have one single average wait time? Can other people actually tell what these graphs say?

by thl on Apr 9, 2013 12:23 pm • linkreport

thl: There are about 180 observations. Each color represents a different quartile. The darkest color is the number of minutes where the wait was less than that 25% of the time. The next color is the number of minutes where the wait was less 50% of the time. The next color is where the wait was less 75% of the time, and the lightest color shows the longest waits reported at any time in the 6 months.

by David Alpert on Apr 9, 2013 12:28 pm • linkreport

So a couple people above have mentioned that they don't like how the APM doesn't stop at Concourse D and the long walk from the station at Concourse C. The planners aren't dumb. They didn't just build a multi-billion dollar APM and not plan it out. The system is intended to serve the airport for the foreseeable future.

In order to accomplish that, it is designed to operate as a loop, with Stops at the Main Terminal, Concourses A and B, Concourses C and D (in their final locations), and future concourses E,F,G, and H, as well as a new south terminal. E and F would be in the Tier 3 midfield Concourse, and G and H would be in the Tier 4 midfield concourse should Dulles ever need that much space. The south terminal would be beyond those, close to the location of the service facility.

Tier 2, (concourses C and D) is supposed to be rebuilt in the coming years. The current building would be destroyed, and a permanent building would be built a little further south, on top of the location of the current Concourse C station. As a part of this contract, the APM would be extended to serve Concourse D as well. They cut that extension out of the original contract to save money.

It should also be noted that Tier 2 will be funded primarily by United. The projections United made in deciding to finance their own new dedicated concourse were made before their merger with Continental. This merger, and the acquisition of EWR as an east coast hub, as well as the poor economy at the end of the last decade, all contributed to the delay of the reconstruction of the Tier 2 midfield concourse.

by Dan on Apr 9, 2013 12:44 pm • linkreport

I was able to figure out the graphs eventually but a solid line denoting median weight time superimposed over the quartile cumulative info wpuld be helpful for folks interested in just a quick read.

by Falls Church on Apr 9, 2013 1:18 pm • linkreport

I bet the peak in the late 2:00 p.m./early 3:00 p.m. hour is in part related to the large Air France A380. The AF A380 departs around 4:15 p.m.; the A380 is a massive aircraft. If there is a bank of departures involving that AF A380 and even one 747 or the Korean Air 777 I can see why there is a spike when the early set of flights depart for Europe.

by Transport. on Apr 9, 2013 2:03 pm • linkreport

I doubt the peak is related to a single aircraft, especially because boarding for a 4:15 international flight is beginning by 3:30, making anyone in the security line close to late.

Rather, there's a bank of European flights in the late afternoon (4-7) that are designed to arrive early in the morning in Europe (and then another series of later flights in the evening). Combine that with late afternoon domestic flights and one can see how it would build.

As for the graphs, I agree they are a bit hard to read. It's great information, but not ideally presented.

1) Scale is too large. It appears the max wait is 40 minutes, so why is the Y axis 60 minutes?
2) The lightest blue is extremely difficult to see because there is little contrast with white. Perhaps an outline would help.
3) The terminology is a bit difficult to follow, combining "median" with percentages. What about "quartile"?

by ah on Apr 9, 2013 3:15 pm • linkreport

Notwithstanding the defense by apologists, your big, expensive AeroTrain, designed for "future travel" is the single reason that I refuse to book a ticket on United that connects at Dulles. The trek from my arriving flight, via the AeroTrain, to Terminal C is RIDICULOUS and will be a burden on travelers for YEARS TO COME.

Any idiot could have seen this problem coming and would have designed an interim fix. I tell everyone I can to avoid Dulles.

by DenverJoe on Apr 9, 2013 6:32 pm • linkreport

denverJoe, can you give me an example of an airport that is designed that is designed for 70 million people a year that has a better transfer setup? If you really hate the design that much I can pass your suggestions along to planners at MWAA. By the way, the c concourse debacle is United's not MWAAs fault. When the APM was designed the concourse was supposed to be completed In a few years. United hasn't passed money to MWAA. So if any idiot could have designed a solution what is yours?

by Dan on Apr 9, 2013 6:59 pm • linkreport

Any idiot could have seen this problem coming and would have designed an interim fix.

You do realize that the current walk at the C gates is the interim fix, right?

by Alex B. on Apr 9, 2013 7:20 pm • linkreport

Could the difference with the East checkpoints vs. the West ones relate to an operation pattern, such as only opening lanes when the West side is full? I forget how it's configured. Also, sometimes there are lanes set aside for "priority" passengers; maybe they account for some of the shorter wait times?

by Graham S on Apr 9, 2013 9:23 pm • linkreport

The pre-check line at Dulles is at the East checkpoint which might drive the average wait time there down vs. the west.

by Jeff on Apr 10, 2013 9:05 am • linkreport

"Also, sometimes there are lanes set aside for "priority" passengers; maybe they account for some of the shorter wait times?"
The elite lanes at Dulles just get you to the doc checker faster, after that they dump you in with everyone else for screening.

by Phil on Apr 10, 2013 11:44 am • linkreport

All of those people packed tightly into waiting lines before going through security are plumb targets for a terrorist wearing a bomb under his coat. The system could not be designed more efficiently for this purpose. A single guy detonating a bomb in a security line would shut down our air travel infrastructure indefinitely. All he'd have to do is walk up and get in line and wait until he's in the middle of many dozens of people snaked in tight lines within yards of him.

That this has never happened is proof that our trillion dollar security theater system is unnecessary.

by Ted on Apr 10, 2013 2:21 pm • linkreport

Not sure that I would agree with you that weekend flight levels equal weekday. While it is more equal than 15 or so years ago, my impression is that there are still fewer flights on weekends or maybe they are just redeployed from weekday destinations.

by Steve Strauss on Apr 10, 2013 4:14 pm • linkreport

The variation in the East checkpoint is caused by the United's four daily departure banks that occur at 8am-9am, 12pm-1pm, 4pm-5pm, and 9pm-10pm. The 4-5 bank includes most of the flights on wide-body aircraft to Europe, as well as the largest number of domestic departures. The size of each bank is evident by the volume at the security checkpoints. The fourth bank (9pm-10pm) is lightest on security at these departures likely rely less on Washington-originating traffic, and more on domestic connections. United operates a classic hub-and-spoke operation at IAD (with concentrated arrival and departure banks) and the data you have provided demonstrates the effect of this on other airport services.

Contrast this to the West checkpoint that many more airlines use, whose departures are spread across the day.

by Zach W on Apr 11, 2013 8:14 am • linkreport

MWAA would have done better to retain the "moon buggy" shuttle buses between the Main Terminal and Terminal C, and also between Terminal A and Terminal C, until the replacement for Terminal C is built and ready for use. This is a non-genius approach, and experimentally it worked better.

The overall trip time for those shuttle buses was lower, and the hassle was MUCH lower, than the current AeroTrain approach. Ignoring the (temporarily) misplaced Terminal C station, using the AeroTrain requires multiple escalators up/down.

Separately, moving between a UA Express flight in Terminal A and a mainline flight in Terminal C also takes more time than before and has multiple sets of escalators on each end.

by Anonymous Loser on Apr 11, 2013 12:13 pm • linkreport

AL: Yes, the escalators are a great point. I once landed at Dulles on a UA Express in A and counted something like 8 escalators (I forget the exact number) to get through the train and out to the main terminal.

Plus, there will be several more to get to the Metro once it opens.

by David Alpert on Apr 11, 2013 12:15 pm • linkreport

I frequently have no choice but to use Dulles Airport. I agree that it is a nightmare and definitely not a model of what a country with the ambitions and the bragging that the USA displays ("the biggest", "the best", "No. 1!" etc.) should have. The trek to terminal "C" is awful, between long walks, escalators, train and then the dingy and disgusting terminal. Last night I arrived at Dulles on a United flight from Houston around 1 am. The flight was 60% full. We had to walk to the "people mover", wait 20 minutes for everyone to arrive; exit to the long walk to the "no return" swinging doors; and then again walk a while and brave escalators and staircases to get to the luggage area where we were directed to the farthest possible luggage delivery belt, #2, another long walk. I feel bad for anyone who is old, with limited mobility, or sick, or who is not familiar with Dulles and has limited or no English fluency. It is really an unpleasant experience. United and the MWAA should be ashamed for the poor service they offer at Dulles! The airport was poorly designed with its separation of the check-in area and the actual departure or arrival gates... It is fundamentally a flawed concept and design that no tinkering around can truly solve. Some day it may need to be totally redone from scratch...

by sagrasan on Apr 13, 2013 11:52 pm • linkreport

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