Post #736: Border patrol: Will there be spillovers from out-of-control states to others?

Source:  Florida Department of Highway Safety and Motor Vehicles.

Well, that’s a fairly important question, isn’t it?  Will we end up suffering for other states’ lack of ability to control COVID-19.  Will our slow and relatively cautious re-opening strategy — complete with mask mandate — all be for naught, given the craziness that was allowed to occur in (say) Florida and elsewhere?

I went looking for even a shred of data to support an answer one way or the other, and I seem to have failed.  All I can say, for sure, based on the above, is that it doesn’t appear to have happened yet.

Above:  Daily new cases in Virginia (blue) and Fairfax County (orange) reported through today, 6/30/2020.

But I came across a few things that I had not realized before. 

Interstate checkpoints

When Florida put in a mandatory quarantine for people from New York, they literally set up checkpoints on I95 and pulled over all the cars with New York state tags?  Tens of thousands of cars were pulled over, drivers’ licenses checked, and individuals required to fill out a form detailing their travel itinerary in Florida.  This was in addition to such screening already being done at airports.

It’s not as if Florida was the only state or area to have done that.  The more you look, the more common this practice appears to have been.

For a while, South Carolina made it illegal for hotels, car rental agencies, and similar accept reservations from persons from some states.  Literally, if you lived in New York City, for the period of time that order was in effect, you could not legally rent a car or reserve a hotel room in South Carolina.

Inter-state transmission of COVID-19 is a true risk.  There are well-documented cases of interstate transmission of COVID-19.  Most recently, cases in West Virginia and other states were traced back to partying in Myrtle Beach, SC.

Further, it appears that the presence of such checkpoints does, in fact, reduce interstate travel.  And mathematical models suggest that quashing interstate travel would help reduce the spread of  COVID-19.  The apparent consensus of expert opinion is that such techniques slow, but do not stop, spread of COVID-19.  So it’s not as if this strategy is without merit.


Cell phone tracking

Second, anonymized cell-phone data could allow us to estimate how many people travel from (e.g.) Florida to Virginia on any given day.  Such information is routinely used in (e.g.) traffic studies, and was in fact used in a study of traffic flow in the Vienna, VA.  And it has been used to study long-distance travel, just not this particular problem.  Here’s an example from Maryland, and another from New York.  I could go on.  Even in Virginia.

So, it certainly would be possible to know the extent to which people from Florida (say) are currently in Virginia.  (Or, at least, some guess at that, based on about 15M cell phones nationally that have (intentionally or unintentionally) opted into such anonymized tracking.)  But as far as I can tell, nobody has done that.

License tag game, but for adults.

Third, for that matter, it wouldn’t take much more than counting out-of-state tags as they cross the border on major interstates.  I would not be surprised, in our surveillance society, if that isn’t already being done.  For sure, they did that in Vermont, but they did it the old-fashioned way — with people sitting at the border, tallying tags.  And, as with actual checkpoints, the more you look, the more states you will find having done this.


The question is, will Virginia, at some point, resort to checkpoints or other methods, as a matter of self-defense?  I can’t imagine Virginia setting up a checkpoint at the Carolina border.  But you never know.  There’s a lot about life today that I could not have imagined.

But to make that decision, you have to know whether the risk of transmission is material or not.  And the starting point for that is to know how many people travel from the current high-active-case states to Virginia.

Privacy concerns aside, I hope that information is being collected.  Even if imperfect, even if it does not count (e.g.) Virginians who vacation in Florida then return.  As far as I can tell, if that information is being collected, it has not been made available to the public.