Making your connection: A RootMetrics review of mobile network performance at airports

07-23-15 | Patrick Linder

Introduction

Hundreds of millions of passengers travel through US airports every year. But whether you’re a seasoned traveler with more frequent flier miles than you know what to do with or someone who flies only once or twice a year, you’ve probably had better experiences in some airports than in others. Good airports share a few obvious characteristics, from ample power outlets to multiple food options to plentiful seating within the terminals. But there’s another, often overlooked trait that good airports have in common: strong and reliable data performance from mobile networks.

After all, airports aren’t just hubs for travel; they also act as hubs for mobile network activity. With mobile access prevented during flights, time spent in the terminal is often a chance when travelers use their phones to catch up on work, stay connected with social media, and find entertainment while waiting for boarding to start. Given the importance of mobile at airports, flight delays aren’t the only slowdown that hampers your travel experience; lagging data performance from your mobile network also acts as a significant pain point. We might be willing to put up with overpriced bottles of water and even accept that delays are part of the travel experience, but poor mobile network coverage can ruin your experience in an otherwise well-designed airport.

To show you which networks and airports offer first-class performance, we tested mobile data performance at the nation’s 50 busiest airports and have brought together the results from the first half of 2015 in this special summary report. Our opening section offers side-by-side performance information for the nation’s five busiest airports. These are the airports where network demands are often highest and performance differences are magnified. Our second section provides in-depth, important carrier highlights and trend information. Finally, we’ve ranked all 50 airports from best to worst to show you where performance takes off, and where your data experience might become turbulent.

In general, we’re seeing improved reliability and adequate (though not always outstanding) speeds at airports, so even if you miss your connecting flight you can stay connected with your mobile network.

How we test

To evaluate how well each network handled typical consumer data demands, we use off-the-shelf smartphones to test performance under typical conditions at the 50 busiest US airports twice each year. Throughout each airport, our scientific test team collects samples at locations passengers typically visit , including at ticketing, baggage claim, and within terminals. In addition to capturing download and upload speed, we test each network’s data performance during consumer-based activities such as checking email or during web/app usage. The best performing network(s) at each airport earns our RootScore Award as a mark of excellence in our consumer-focused testing.

Performance at the busiest airports

To give you direct, network-to-network comparisons, we've brought together results from our testing at the nation's five busiest airports (based on 2013 enplanement stats from the FAA, the latest stats available at the time of testing): ATL (Hartsfield-Jackson Atlanta International), LAX (Los Angeles International), ORD (O'Hare International), DFW (Dallas Fort-Worth International), and DEN (Denver International). All told, more than 164 million passengers passed through these five airports in 2013, making them competitive battlegrounds for the carriers and intense pressure spots for consistent network coverage.

Whether you're looking to download your boarding pass, check email, or view Twitter, your data experience at airports is dependent on the speed and reliability of your network connection. Our cross-carrier comparisons show you both download and upload speed at these airports. Our reliability testing, meanwhile, considers the two hallmarks of your network experience: can you connect to the network, and can you then stay connected until your task is complete (i.e., did you experience a data failure)? For this report, we focus on reliability rates during our web/app testing, which serves as a good proxy for overall reliability.



The results show that Verizon generally offered faster speeds than the other networks at the nation's five busiest airports to go along with excellent reliability. The exception to the rule was at Denver International. At Denver International, T-Mobile won our RootScore Award and Verizon's speeds were noticeably slower than in most of the airports we tested. AT&T offered generally strong reliability across all five airports, but was less consistent with speed. Sprint, which typically trailed the other networks, performed well at O’Hare International. Sprint has invested heavily in the entire Chicago metro area and performance at O’Hare seems to have benefited as well. The news is mixed for T-Mobile. Although it recorded extremely fast speeds at Hartsfield-Jackson and even outpaced Verizon at Denver International, its download speeds at Los Angeles International and O'Hare were slower than those of the other networks and its reliability—especially in staying connected until our web/app test was complete—lagged behind at LAX.

download-upload-speeds

These cross-carrier comparisons also show just how varied performance can be from airport to airport. Mobile networks face unique provisioning challenges at airports. Passenger flow, for instance, can lead to mobile congestion, while dense _globaling materials and underground locations can present RF difficulties. Restrictions on tower and antenna placement, meanwhile, make adding extra capacity more difficult for carriers. In short, strong performance at one airport—or even in a surrounding metro area—does not guarantee good coverage within an airport.

The impact of provisioning challenges and the variation from airport to airport are exemplified in the marked drop in performance seen at LAX. Both speed and reliability were challenging for most networks at LAX. T-Mobile shows the extremity of this performance drop-off: across all 50 airports, T-Mobile recorded both its slowest download speed and its worst rate of staying connected during our testing at LAX. And while Verizon performed better than the other networks at LAX, its 13.3 Mbps download speed was still much slower than what Verizon offered at many other airports.

Such vast differences in speeds from airport to airport, and from network to network, can have a marked real-world impact on your travel experience. Consider it in terms of a common traveler activity like downloading the latest episode of your favorite series in HD to watch during your flight. As our chart shows, your experience at Hartsfield-Jackson (ATL), the nation’s busiest airport, could be wildly different from your experience at Los Angeles International (LAX), the nation’s second busiest airport.

lax-hartsfield-tables

Network-by-network highlights

To give you additional carrier-specific insights, we've also included individual summaries of each network's performance across all 50 airports. As you'll see, no network aced all aspects of our testing at every airport. There are, however, important performance differences between the networks.

att-donut

Showing improved performance, AT&T earned three more RootScore Awards in this round of testing compared to our testing in the second half of 2014. AT&T’s award tally bump was at least in part due to noticeably improved data reliability.

Already a strong reliability performer, AT&T improved in both getting connected and then staying connected when comparing this round of testing to that from the second half of 2014. We use a high bar in our reliability testing and look for networks to offer at least a 97% success rate in our web/app testing. This 97% threshold reflects performance that would pose little to no noticeable disruptions in your everyday mobile life. We were able to connect to AT&T’s network in at least 97% of our tests at 47 of the 50 airports, compared to a mark of 42 airports last time. Once connected, AT&T also proved extremely reliable at holding that connection. We completed our web/app test more than 97% of the time at 42 airports, compared to 38 airports in our previous round of testing. Second only to Verizon in these reliability metrics, AT&T especially outdistanced Sprint and T-Mobile when looking at how often we could make that initial network connection. If reliability is your primary concern, AT&T proved to be a strong option in our airport testing.



AT&T’s speed performance, however, left it in the middle of the pack and clearly behind speed leader Verizon. Our speed distribution chart shows AT&T’s results split across a wide range of speeds. Led by a 40.7 Mbps download performance at Atlanta’s Hartsfield-Jackson International, AT&T’s top speeds were fantastic. AT&T delivered download speeds above 10 Mbps in 22 of the 50 airports. At these speeds, consumers could easily complete the vast majority of everyday mobile activity. On the other hand, AT&T dipped below 5 Mbps for download in 16 airports, including median download speeds below 3.0 Mbps in several airports that could cause disruptions for consumers. AT&T’s upload distribution showed even more likelihood of slow speeds. Only Sprint had more markets dipping into the bottom 0-5 Mbps speed range for download and upload.

The bottom line: AT&T’s performance was a mixed bag, with improved reliability but slow speeds at a number of airports.

att-chart

sprint-donut

Sprint didn’t win a RootScore Award in any airport during this round of testing (in the second half of 2014, it earned one RootScore Award). The good news for Sprint customers, however, is that the network showed across-the-board improvement in reliability. We were able to connect to Sprint’s network in more than 97% of tests at 31 airports, compared to only 21 airports in our last round of testing. And we were then able to complete our web/app task more than 97% of the time at 34 airports, compared to 28 last time.

The biggest performance drawback for Sprint is speed, which continues to trail those of the other networks. As our speed distribution chart shows, Sprint’s speeds consistently fell into the slowest range. Whether looking at download or upload, no network had more markets fall into the 0-5 Mbps range. Moreover, Sprint's download speeds never exceeded 15 Mbps and upload speeds never surpassed 10 Mbps.

The bottom line: Sprint’s reliability enhancements deserve praise but the network still has room to improve when considering speed.

sprint-chart

tmobile-donut

Compared to the second half of 2014, T-Mobile added three RootScore Awards to its tally. With 20 total RootScore Awards, T-Mobile trailed only Verizon in our tally of airport wins.

Looking into T-Mobile’s airport performance, however, shows an interesting split. On the one hand, we saw marked improvement in being able to access T-Mobile’s network: in the second half of 2014, we accessed T-Mobile’s network during our web/app tests more than 97% of the time at 21 airports; in this round of testing, that number jumped to 31 airports. On the other hand, staying connected to T-Mobile’s network until our web/app test was finished proved slightly more difficult in this round of testing. We were able to complete our testing more than 97% of the time at 47 airports during the first half of 2014 but did so at 40 airports this time.

T-Mobile’s speeds were similar to what we saw with AT&T’s network: good topline speed at some airports and markedly slow speeds at other airports. T-Mobile offered extremely fast speeds at Atlanta’s Hartsfield-Jackson Airport, recording 42.8 Mbps for download speed. At the other end of the spectrum, T-Mobile managed only 0.1 Mbps in our testing at LAX.

The bottom line: T-Mobile delivered solid performance but still recorded slower-than-ideal speeds in a large number of airports. If speeds can improve at those slower airports, T-Mobile could become an even more attractive option.

tmobile-chart

verizon-donut

No matter how you look at it, Verizon topped our airport performance testing. Although Verizon’s 29 wins are two fewer than what it earned in the second half of 2014, Verizon still won more RootScore Awards than any other network. Verizon continues to offer outstanding performance and a marginal drop in award tally is more a sign of increasing competition from other networks than a slip from Verizon.

Verizon’s reliability was stellar. We were able to connect to Verizon’s network more than 97% of the time at 49 of the 50 airports tested (an increase of one compared to our last round of testing). Our ability to stay connected until our web/app testing was complete was similarly outstanding, with success rates topping 97% at 46 of the 50 airports (likewise an increase of one from what we found during our last round of testing).

In general, Verizon’s speeds were also impressive. More than any other network, Verizon’s speed distribution shows performance weighted toward the top end of the scale. Verizon also recorded the fastest median download and upload speeds of any network, with a blazing-fast 68.8 Mbps download and 40.4 Mbps upload at Chicago’s Midway International. That said, speeds were not fantastic everywhere and median download speeds even dipped below 1.0 Mbps in three airports (Philadelphia International, LaGuardia, and Reagan National).

verizon-chart

The bottom line: Verizon led the way in our testing and offered both fast and reliable performance in the vast majority of airports we visited. Although Verizon’s reliability was particularly impressive, the bottom bucket of its speed distribution shows room for improvement.

Ranking the airports



To give you a comparative view of how performance differs depending on where your travel takes you, we’ve ranked all 50 airports from best to worst for network coverage. Our airport rankings are based on an average of all networks’ RootScores at a particular airport, weighted by the estimated national percentage of subscribers for each network. In other words, performance scores from networks that have more customers are weighted heavier than scores from networks with fewer subscribers.

After finishing at #7 in our last round of testing, Atlanta's Hartsfield-Jackson International topped our airport rankings in the first half of 2015. Offering a combination of fast speeds and strong reliability from all four networks, performance at Hartsfield-Jackson is all the more impressive given how many passengers place demands on the mobile networks each year. Seeing more than 45 million passengers annually, Hartsfield-Jackson not only topped our rankings but also sits at the top of the FAA's list of airports with the most annual passenger traffic.



As you might expect based on our earlier two sections, however, traveling through a big airport certainly does not guarantee great performance. With the exception of Hartsfield-Jackson, the busiest airports generally did not perform well in our comparative rankings. Denver International, the nation's fifth busiest airport, managed only a ranking of 42 in our comparison of mobile performance results. Performance was even more challenging at LAX. Ranked second for annual passenger traffic, LAX fell all the way to 48th out of 50 in our mobile performance rankings. Finishing at 18 in our rankings, relatively close John Wayne Airport easily outshined LAX for mobile performance.

Differences in mobile performance weren't as sharp when comparing airports within the Chicago or New York areas. Performance wasn't spectacular at O'Hare, which finished at 34 in our rankings, but Midway also struggled and finished at 37. The New York and tri-state area was led by Newark's 13th place finish, with JFK offering middle-of-the-pack performance and finishing 21st, and LaGuardia coming in closer to the bottom at 38th.

It's a different story if you're flying through Washington, DC. If mobile performance is a primary concern and you have the option to choose which airport you travel through, Dulles clearly outperformed Reagan National: ranking at number 7 overall, Dulles landed near the top of our mobile performance list, while Reagan National finished near the bottom at 43.

Explore for yourself

Check out the table below to see not just the full ranking of airports but also individual network speed highlights from the first half of 2015. Full details for each airport can be seen by viewing individual Airport RootScore Reports.

Beyond airports, we’re busy testing networks across all the spaces of your mobile life. Stay tuned for additional reports showing how the networks compare at busy venues, transit stations, and more. Coupled with our look at nationwide, state, and metro performance, it’s a full nation-to-neighborhood view.

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