How Far Will COVID Spread From the Airport Because of the Holidays?

How far will COVID travel this holiday season? It’s a legitimate question and it has experts worried. The TSA reported that over a million travelers passed through TSA checkpoints on December 28th and although this is only 50% of the total travelers a year ago, it’s still 100% more potential carriers of the virus than a year ago.

While the TSA, along with the airlines, face significant hurdles in ensuring the safety of travelers, local and state governments will undoubtedly face similar or greater hurdles if COVID numbers tick upwards during the holiday season.

My expertise is not in air travel safety — they are in quantifying consumer perceptions and consumer movement. Therefore, let’s dive in and assess the potential for community spread and understand what happens after travelers exit the airport.

Methodology

Using a sample of publicly-available posts pre-COVID — we are able to track some of the places people visit within a month of stepping foot in Dulles International (IAD), Reagan National (DCA) or Baltimore/Washington International Airport (BWI). Since our sample included roughly half a million data points, we isolated the first two locations people checked in at after IAD, DCA or BWI to reduce the scope of the study.

The two questions we want to answer are:

How far do people travel in the month following their flight into the Greater DC Metropolitan Area?
How do these patterns of movement differ between IAD, DCA and BWI?

Global And Domestic Flights From DC

Although the focus of our study is to examine the potential spread of COVID from the airport to the local community, our data included many travelers who were taking off from DC to go elsewhere as well as travelers who were coming from international locations to the DC metropolitan area.

Domestically, we see movement and concentrations in the expected cities: New York, Boston, Philadelphia, Chicago, San Francisco, Miami, Austin, Dallas, LA, Denver, Cincinnati, etc. Although we’re about to hone in on the consumer movement of individuals landing in BWI, DCA and DUL, it would be fascinating to additionally examine the local routes travelers take in each of these cities in a future study.

Drive-Time Locations Around The DMV Region

When we isolate journeys that depart from one of the three major airports around DC to locations within a ~250 km radius (roughly BWI to Richmond, VA or Dulles to Philadelphia), we can see just how far COVID can go via individuals leaving the airport.

Some of the farthest locations from the airports in the study were out to Pittsburgh, PA, Roanoke, and Norfolk, VA (around 3–4 hour drives without traffic). Whether it’s due to the accessibility of the DMV region airports or the price of tickets to fly in and out, it’s clear that COVID has the potential to travel much farther from the airport than just the surrounding metropolitan area.

In other words, the virus can easily travel 100+ miles just from families picking up loved ones or a traveler renting a car at the airport.

Although states have instituted emergency travel orders this year that have directed travelers from states experiencing COVID hot spots to quarantine for 14 days, like before, these measures will be difficult to enforce during the holiday season.

Geographic Movement by Airport

Breaking down traveler journeys by airport, we are able to see different geographic patterns emerge. Travelers passing through Reagan National stick around Washington DC and the surrounding suburbs in Maryland and Virginia. Similarly, travelers passing through Dulles generally stay around the Northern Virginia region. BWI however, has two focal points — DC and Baltimore. It’s also worth noting the distance that travelers head from BWI and Dulles in particular into the suburbs and non-urban areas.

Heading Into 2021

This article is meant to foster the conversation around precautionary measures to mitigate virus transmission within local communities that are located within driving distance to a national or international airport.

While we have all heard about contact tracing from the news or possibly downloaded an app or received a call ourselves, these visualizations are meant to illustrate the complexities and challenging patterns that traveler movement poses to effective tracing.

There is no single solution to eliminate the potential spread of COVID-19 via travelers. Contact tracing and 2-week quarantine policies are a start, but the distance COVID can travel and the sheer interconnectivity of a potential transmission network means that the 2020 holiday season heading into 2021 will undoubtedly be a difficult time for America.