Rocky will give a warning bark if he is in the car and some gets to close, but only if DH or I are in the vehicle with him. It is not a continous bark. He will bark once just so the people basically know he is there. There have been a few ocassions where he has barked several times, but I have noticed that it is always at the same person and he will do it regardless of where he is or the circumstances. (For some reason, he just does not like this guy, never has since the first time he saw him, and he walks by our house on a regular basis)