As a matter of logic, Jack is right.

Incidentally I was nearly rammed three times today by the same bloke whose eyes were cast down from the road towards his lap. Yes, I watch my mirror. By the time he turned off I had let him overtake me (that worried me a bit too) and I think that he was not texting but reading a mapping program on a smartphone or less likely satnav.

Since I was however in a dirty great Shogun that isn't mine (with headrests and with belt on), I was less worried than I might have been. He was in a Corsa about the size of the Shogun's towball.