Nope, I am a black one. Went through about 10 to 11 AM. Traffic was much heavier than seen on your cam. Other than those cars seen at Superchargers I do not recall passing or being passed by another "S" the entire trip, either way.
I drive frequently from Raleigh to PA I85/I95 & have yet to see another Model S which is surprising. Granted, we often drive at night and I'm asleep for half of the trip. But I see MS frequently on I40 in the Raleigh area. Go figure.