Remember when car following distance was based on distance, like 1 car length for every 10mph, and then they changed to a "3? second rule" ( which I still believe is idiotic)?
Anyway, if the virus remains virulent for 4 hours when airborne, shouldn't the distance rule be, the distance air travels in the ambient wind conditions in say 4 hours?
Its "feel good distance theater for the masses" anyway.
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.