Monday, April 20, 2020

Subways and virus

The Subways Seeded the Massive Coronavirus Epidemic in New York City is an intriguing and delightfully written article by Jeff Harris

New York City’s multitentacled subway system was a major disseminator – if not the principal transmission vehicle – of coronavirus infection during the initial takeoff of the massive epidemic that became evident throughout the city during March 2020. The near shutoff of subway ridership in Manhattan – down by over 90 percent at the end of March – correlates strongly with the substantial increase in the doubling time of new cases in this borough. Maps of subway station turnstile entries, superimposed upon zip code-level maps of reported coronavirus incidence, are strongly consistent with subway-facilitated disease propagation. Local train lines appear to have a higher propensity to transmit infection than express lines. Reciprocal seeding of infection appears to be the best explanation for the emergence of a single hotspot in Midtown West in Manhattan. Bus hubs may have served as secondary transmission routes out to the periphery of the city

Later in the article

The Metropolitan Transit Authority’s decision to cut back its train service to accommodate the reduced demand may have indeed helped to shore up the agency’s financial position, but it most likely accelerated the spread of coronavirus throughout the city. That’s because the resulting reduction in train service tended to maintain passenger density, the key factor driving viral propagation (Goldbaum and Cook 2020). How ironic it is that, from the public health perspective, the optimal policy would have been to double – maybe even triple – the frequency of train service. The agency’s decision to convert multiple express lines into local service only enhanced the risk of contagion (Goldbaum 2020). How ironic it is that the preferred policy would have been to run even more express lines. We have not seen any public data on the incremental cost of the agency’s decision to begin to disinfect subway cars twice daily. Still, it is natural to inquire why the cars weren’t disinfected every time they emptied out of passengers at both ends of the line.
Why not continually? There are a lot of unemployed people being paid by the government. Why not send a cleaning crew of 10 to continually wipe down each train, monitor mask use, and social distance protocols?

London apparently made a similar blunder.

Comment: I've been harping for a while on the fat-tailed distribution of activities. Shut down the super-spreading activities. Shut down dangerous activities not specific businesses. Consider lost income.

But how do you shut down the subways in New York City? How do you run subways in a vaguely safe way? If the virus lasts, getting around NY is going to be a mess for a long time.


  1. Unless something miraculous happens people are going to start leaving their cages, whether authorized or not. You can't monetize an economy and pressures will build to reopen, ready or not.

    I'm in the "or not" camp. There's no medication and no vaccine. Everyone is going to get the virus eventually and not everyone will survive. There will also be a surge in rehab hospital demand because quite a few survivors will have some type of chronic impairment.

  2. John, a hard to answer question to be sure, but do you see any long term shifts away from high density living( e. g. cities) and towards more suburban lifestyle, a la what we saw during the big migration during the 50s, 60s, and 70s?

    1. I'm not John Cochrane, but I'll offer my best guess: probably not any big impact on a city like New York if we have an effective and widely available vaccine within 1 or 2 years.

      I suppose one wild card even in that scenario is if businesses and workers decide they both like greater levels of work from home. James Gorman, Morgan Stanley's CEO, has made noises in this direction already, talking about seeing a future where Morgan Stanley pays for "much less real estate" because not every worker needs to come into the office every day. A suburban house with space for a nice home office set-up could seem more attractive, and the long commute is only 2 or 3 days per week rather than 5.

      One tangential consequence I can see is that it kills additional money being spent on light rail and commuter rail projects in Sunbelt cities. The taxes/bonds for these projects can already be fairly contentious in cities like Dallas, Houston, Phoenix, Nashville, Charlotte, etc.: there's an organized opposition with meaningful support. I could see associations of the coronavirus pandemic and public transit being enough to push votes the other way in these places where spending a lot of money on light rail is already a dicey political proposition.


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