Houston Airport System Uses Bluetooth Sensors to Measure Wait Times at Security Checkpoints

Kimberly Kaiser
Published in: 



Project: Checkpoint Wait Time Study

Location: George Bush Intercontinental Airport

Owner/Operator: Houston Airport System

Cost: $25,000

Performed By: Purdue University's Joint Transportation Research Program

Duration: 2 weeks

Timing: Late summer/early fall 2010

Data Volume: 200,000 records

Results: Wait times at various security checkpoints were determined; additional long-term data collection initiated

In the last ten years, Bluetooth technology has been implemented in everything from cell phones to computer mice. More recently, Houston Airport System (HAS) has used it to facilitate data collection.

In June 2010, the new HAS director, Mario Diaz, wanted to track how long it was taking for passengers to get through security checkpoints. Measuring the wait times fell to Lisa Kent, chief information officer for the three-airport system. Intent on finding an automated way to collect the data, Kent and her team discovered the work of Dr. Darcy Bullock, director of the Joint Transportation Research Program at Purdue University. Bullock had conducted a study using Bluetooth sensors at Indianapolis International Airport the year prior, and HAS commissioned him to perform similar research at George Bush Intercontinental Airport (IAH).

The $25,000 project was conducted over two weeks, including the long Labor Day weekend, in 2010. Nine Bluetooth sensors were placed around IAH: four outside, but still on airport property, and five inside Terminal C.

The sensors were positioned to pick up signals from passengers' Bluetooth devices as they passed by. "The sensor simply notes that a signal is in the area," explains Karla Petri, manager of consumer research for InterVISTAS Consulting. "It can't tell if the phone is in use … if someone is on their phone or texting … or who owns the phone. You have no demographic information; it's purely anonymous. (Although InterVISTAS was not involved with the IAH project, it provides Bluetooth services for airports throughout the world.)

Two of the outside sensor stations were located on roadways to capture data as passengers entered the airport property, and two were positioned adjacent to vehicle entrances at the Terminal C parking structure. Inside Terminal C, there were four sensors on the sterile side and one located pre-security.

See Figure 1.

"Houston Airport System really wanted to understand the whole 'airport experience'," says Bullock. "Disney uses that term, but I think it's a very good customer service perspective for an airport to have."

Gathering Data

Kent says it was easy to calculate wait times based on data collected by the Bluetooth sensors. Any time a passenger with a Bluetooth device passed through one of the sensors, the device's unique media access control (MAC) address was captured. After that, it was a matter of matching MAC addresses as they passed from one sensor to the next, she explains.

"You can calculate transit time based on the time stamp of when the sensor picked up that particular MAC address," Kent says.

According to Bullock, about 10% of the devices currently being used are in "discoverable mode," which means they chirp out a unique multi-number MAC address. Actually, a full MAC address isn't necessary; a few digits are enough to make a match for determining wait times, he notes.

Crunching the Numbers

After collecting data for two weeks, the research team accumulated about 200,000 records about visitors' travel time - potentially a DRIP (data rich/information poor) situation, as Bullock calls it. Digesting and analyzing the information to help characterize the "airport experience" at IAH was the next crucial step.


Bullock and the team from Purdue created charts that illustrate wait times on a daily and hourly basis. The charts depict the longest, median and shortest wait times as well as the volume at each checkpoint and the number of lanes open. Figure 2, for instance, shows that the median wait time was approximately 25 minutes at 10 a.m. (see section i) and volume didn't change much from 8 a.m. to 10 a.m. (section iii). It also, notes Bullock, shows that wait times jumped when the south lane was closed at 10 a.m. (section ii).

"You can see the impact that lane closure had on wait time," he says. "Here's an example of how good quantitative data might suggest … that wasn't the right decision to close." Bullock acknowledges that other factors such as a staffing shortage may have necessitated the closure, but the data demonstrates the effect it had.

After reviewing other data, airport officials were taken aback by the number of people driving straight through the airport.

"At IAH, there's a main roadway that comes in from the south and another roadway that departs to the east," Kent explains. "We were surprised by the volume of traffic that was going between those two points. It was clear (by the short duration of time in between) that vehicles were not stopping; they simply passed through."


On one survey day, 47% of the traffic that entered on one of the roads went directly out on the other - significantly more than expected, notes Kent. While a 47% pass-through rate may not be an everyday occurrence - an accident could have caused traffic problems - it nevertheless raised concerns.

"From an airport perspective, that added a lot of volume on our roadway that didn't actually conduct business with us," she explains. "It gives us some ideas for the future on how we might design the roadways or how we might need to allow for additional traffic."

More Monitoring

Based on its two-week study last year, Kent reports that HAS intends to implement long-term Bluetooth data collection. In late August, HAS conducted a density study to reevaluate the number of sensors that will need to be added.

From a customer service standpoint, HAS is interested in sharing real-time data about security checkpoint wait times with passengers.

"Most people are very interested in understanding or being able to identify how long they might need to allow to get all the way out to the gate," relates Kent. "The idea is that we would push that information real time to our website, but also develop some applications that could be used for some of the big phone manufacturers like iPhone and Droid so passengers might actually be able to check wait times before they leave their home or workplace."

The density study will help determine a viable sample size to ensure that HAS will collect enough information to yield statistically accurate data, Kent explains. "At that point, our goal is to have the Bluetooth sensors deployed for all the checkpoints within the Houston Airport System as well as the federal inspections building at Bush Intercontinental."

Officials hope to deploy Bluetooth sensors throughout the system, which includes Bush Intercontinental, William P. Hobby Airport and Ellington Airport, by June 2012.






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Giving back to the community is central to what Charlotte Douglas International Airport and its operator, the City of Charlotte Aviation Department, is about, and last year was no different. 

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This whitepaper highlights the construction projects, initiatives, programs and events that validate Charlotte Douglas as a premier airport.

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