I've puzzled over this as well. Surely, the other car's cruise control isn't calibrated to the same 1mph increments as mine, yet it somehow works out. I wonder

I've puzzled over this as well. Surely, the other car's cruise control isn't calibrated to the same 1mph increments as mine, yet it somehow works out. I wonder if it's an interaction with the leading driver. Perhaps they consciously or subconsciously keep distance from the car behind?