I havent had to dodge any shredded tires yet, but I-75 is covered in bits of retreads every day. It is probably only a matter of time, so i keep on guard and dont hang around when passing 18 wheelers.
I was riding along one day with the visor on my full face helmet open and some jerk throw a cigerette butt out of the car window. Had to stop to take the helmet off to get the cigerette butt out. Oouch.