Depending on the age or breed of the dog, some dogs will instinctively want to lunge at people, pets or vehicles when they go out. Quick reactions to objects and people is a natural form of development for dogs. Just think of how a baby reacts every time they hear something new.
What you want to do is socialize your pet to such stimuli beforehand, so he gets used to these noises enough to ignore them when they show up.One way is to get hold of a cd or dvd that has all different kinds of street noises on it. You can play this on the television or radio in front of the dog, and listening to these noises may get him desensitized to them so he ignores them when he goes outside.
Another thing you can do is exercise the "stop, sit and stay" commands. If you haven't practised these with your dog yet, you can do so in the privacy of your home first. This in itself will not deter a dog's reflex action to lunge at people and objects, but it's a training tool you can use on the walk when he does. At each time he lunges, you can stop the walk, and tell him to "stop, sit and stay" for a full 60 seconds before moving on. You can do this every time he lunges or barks, and before long, it will become so tiresome for him to stop sit and stay that he may cease to lunge altogether.
