I will start my response with this:
I am the proud owner of an American Pit Bull Terrier (otherwise known as a "pitbull"). The American Pit Bull Terrier (APBT) is not only our American Heritage Dog, being a breed that is as american as apple pie blue jeans, but it is probably one of the best family dogs that you could own.
So, not that I take offense, but this thread should be labelled "what should I do if attacked by an out of control
dog?" ANY dog that is large enough and mean enough to be a concern is a problem - not "pit bulls" specifically.
That said, certain dogs do have physical attributes that you must be careful of and take into consideration for your self-defense plan.
On top of being a great dog around family and kids, my APBT is also being trained for SAR (search and rescue) and protection work. I will say that there are some noticable physical traits that should be considered;
CLIMBING is one of them. German Shepards and Malinos that we work with can climb when trained. With APBT, it happends to be an inherent quality in the breed. My dog has the abilities (although he doesn't always use these abilities unless highly motivated) to climb fences, and trees. My dog is a small 50lb dog, but has taken running leaps where his hind legs have reached my chin level. Some dogs are very athletic naturally; so consider this point when considering escaping from certain animals.
As to a self-defense plan:
1. In the immediate, PEPPER SPRAY is your best friend against almost any dog. Pepper spray ruins the motivation of dogs to hurt you. This will work almost everytime; I only say almost as a disclaimer, but I haven't heard of it NOT working (unless the dog is rabid or drug induced).
2. Keep on your neighbors asses if they are doing cruel things to the animal to make it mean. If anyone is neglecting or abusing animals in your neighborhood, take responsability and report it. And keep reporting it! With any luck, the scumbags will have their pets taken from them. The biggest problem with dangerous dogs is that the owners have usually made them that way. Go after the owners within the limits of the law, but relentlessly.
3. If there is no visable signs of neglect or abuse, see if you can get to know the neighbors dog. See if you can "meet" the dog with the owners permission. Bring it a food motivator like cut up hot dogs. Meet the dog several times. Say "hi" to it when he see's you. All of these things add up; a lot of times fears of neighborhood dogs have more to do with the dogs neighbors then the dog itself. Befriending the dog does a couple of things; #1. it helps disipate your fears, which all do respect may in fact be irrational; and #2. it will aquaint the dog to you so if there is ever an incident (like he gets out of the yard or something) he is more likely to listen to you and therefore be less of a threat.
As to APBT; these dogs are incredably people oriented and friendly by nature, even though they may seem frightening. They don't have natural human aggressive or territorial tendencies like "guard dog" breeds (dobermans, rotts, etc.), which is why they often make terrible guard dogs, especially when it comes to property protection. So, don't let the intimidating outer shell fool you.
Lastly: Although I have mentioned some breed specific things regarding APBT; chances are your neighborhood friend isn't a pure APBT anyways. A good way to tell is size; APBT don't usually exceed 60lb if they are healthy; and that would be considered a very large pit. There are some who have breed large pits going as heavy as 90 lbs or so, but that is incredably rare. If it is this monster of a dog, then chances are it is a lab-pit mix, boxer mix, american bulldog, or some other such breed.
Not that it really matters for your self-defense plan. But, just do your homework if your really curious as to the breed. I have run into many owners who have introduced me to their "pitbulls" when the dog was in some cases nowhere near being the actual breed.
Good luck; with some common sense you shouldn't need it!
Paul Janulis