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The Theory Of Mass Transit Safety

masked mass transit riders on a New York City subway car.
photo by Marc A. Hermann, courtesy the Metropolitan Transportation Authority of the State of New York, licensed under CC BY

With finances devastated by the pandemic’s destruction of demand, public transit agencies are desperate to explain why riding subways, buses and other conveniences adds little to riders’ risk of illness – at least in theory.

Their big problem is that in reality, the theory does not always apply.

This fall, a study commissioned by the American Public Transportation Association found no direct correlation between public transit use and COVID-19 spread, either in New York City or elsewhere in the world. Yet nobody is impressed with public transit boosters extrapolating that New York City’s transit system, packed with its pre-pandemic load of 5.5 million daily riders, was not a major contributor to the early and horrific spread of the novel coronavirus through the five boroughs. The governor is presently telling city residents that indoor restaurant dining is unacceptably dangerous, even with six-foot table spacing, capacity limits, large-scale masking except when seated, and physical barriers. How is anyone supposed to believe that the virus did not spread among unmasked commuters, jammed cheek by jowl on platforms and in vehicles, in the critical early weeks when there was virtually no testing because few appreciated that the virus was already present? Claiming that the situation did not at least seed the pandemic into the apartment buildings, elder care facilities and workplaces where it exploded a few weeks later just undermines the more valid assessments of the risks of traveling today.

The Wall Street Journal reported last week that NYC transit officials are coordinating with the Department of Homeland Security and the Massachusetts Institute of Technology to try to more accurately determine how COVID-19 spreads on buses and trains now. Researchers will use empty vehicles that aren’t in service. This may teach us some things about how aerosol-borne virus travels in isolation, which has its use. But it still won’t reflect conditions in which public transit riders actually travel.

The risks involved in taking public transit are manageable, when they are well managed. The American Public Transportation Association study focused on well-ventilated trains and buses, where riders wore masks properly. With adequate spacing and consistent masking, riding on a bus or train does not appear to be a high-risk activity. That does not mean it is carries zero risk, of course. Any trip requires a calculation of the trade-offs. A healthy child, teen or young adult is in little danger of becoming seriously ill from taking such trips to reach school or work. If that traveler does not need to have close contact with anyone who is much more vulnerable, such trips can be readily justified – at least on paper.

In practice, however, every journey requires travelers to surrender control over their immediate environment. Delayed trains may lead to a buildup of crowds on the platform. Service disruptions may put more people into a subway car or bus than can stay the recommended six feet apart. Choosing to pass up an available train because it looks too crowded means risking that you won’t arrive where you need to go at the time you need to be there. Boarding a train that is more crowded than you would want because a trip should take only a few minutes means risking that the train could become stuck in transit, exposing you for longer than you expected. The potential for severe service cuts could soon make all these scenarios even more likely.

Similarly, airplane cabins – with their effective air exchange and ventilation systems – mean exposure in flight should be minimal if passengers are masked and spaced apart. But many hard-pressed airlines are filling their seats again, and passengers must remove masks to eat or drink in flight. Advanced onboard ventilation systems also only work during boarding and deplaning if they are run at full strength off turbine or auxiliary ground power, which is not always the case. They don’t work at all on the jet bridge, inside the terminal, or in the ground vehicle traveling to and from the airport.

Then there are the antisocial individuals who are convinced that mask requirements may apply to other people, but are purely voluntary for them. Even the strictest rules cannot be enforced 100% of the time. These narcissists add an extra level of avoidable risk for everyone unfortunate enough to cross their paths.

Life must go on, even amid a pandemic. Some people must travel. Some will thoughtfully consider the risks and choose to travel anyway, taking reasonable precautions as they do. And some will behave with little thought for themselves or for others. Some humans are just wired that way, and no humans are perfect. We all make mistakes.

One of those mistakes is to tell the public that it is overestimating the risk in using mass transportation, based on ideal or theoretical conditions. Travelers have to travel in reality, and that is where the risks are.

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