Sold car .now the owner is driving the EZTAG lane under my name

[chasinthesun]

I have a bill of sell with the buyer ,anything else that I may need to get them on the right track and off my back ?I hate unresponsible buyers ,the guy said he was heading down to the DMV right away to establish new ownership ,3 violations so far since the sell.
Going back some 10 yrs ago I had a letter from a Calif. city showing me a car I had sold earlier that yr. that had a parking voilation ,a pretty big price tag was with it.