A couple of things in error.
"Pit Bulldogs" - actually, any Molossid except, perhaps, the Fila Brasilero - is less likely to attack you than just about any other breed of dog. Why is this so? Well, they aren't easily intimidated so they don't respond out of fear. The gamebred Pit Bulls are not at all likely to attack you because historically the "man fighters" were always put down due to the belief that the man fighters were not game and no one wants a non-game Pitdog... Besides, a pissed off Pit Bull snapping at my face is not my idea of a great time.
There is also nothing unique about their jaws which allow them to "lock" or tear flesh more efficiently. They probably do not possess the strongest jaws, either. What they DO have is a trait called gameness coupled with plenty of musculature of the jaws, neck,shoulders and the ability to take a tremendous amount of physical abuse. The "gameness" genes and protection drive seem to be diametrically opposed. Thank God. However, a Pit Bull doesn't require all of that gameness of a well-bred pit dog to do you or I in and that is what we're facing in the urban and suburban jungles for the most part.
Somewhere, some institute did a study of dog breed personalities and confirmed what I just typed. I'll try to find it.
Now, those who think a "swift kick" will stop a determined dog may need to think again. Have any of you seen a working strain dog work? How about a Dutch Shepherd, Belgian Malinois or the pea-brained media's "darlin', the Pit Bull actually work? I can assure you that a kick or punch will not stop them. Ditto for any of the large protection breeds such as Rottweilers, Bouviers, Giant Schnauzers and any of the mastiffs.
I ride my all terrain bike such that I can carry my M&P or my 1911 since it's not so damaging to the skeletal system as jogging with nearly 3 lbs on my strong side. I also carry a fighting knife as well as pepper spray mounted to the bike.
True story.
I was biking home on the sidewalk when I noticed a large American Bulldog unleashed looking my way. He's probably no more than 60 feet away and he was on his feet and moving in my direction. I was coming to a stop light and there was a long line of cars stopped at the light. I slowed down, uncovered my pistol and had my hand on it as I slowly passed the home with the loose dog who simply watched me go by before his owner called him. Well, you can imagine the look I got from the line of automobiles as I looked back at them and covered my weapon. I nodded, took a sip from my Camelbak and continued peddling.
Now I simply ADORE animals, especially dogs and especially Molossids (Mastiffs and Mastiff-derived breeds), but I'd not hesitated to shoot a dog - especially a Molossid - if it were threatening to bite me. You'd not want to be grabbed by one.
I also know of police officers who shot Pit Bulldogs with .357 Magnum as well as .40 S&W and STILL get mauled. Such is the tenacity and quickness of a determined dog. Underestimate them at your own peril.
One other thing I've done to "fear innoculate" myself from aggressive dogs is don the sleeve while a PPD attacks the sleeve. I can tell you now the intensity and strength is phenomenal as is the pressure they apply to the sleeve. My next step is to don the suit and have a Malinois run me down. The manner in which they leap into the target is a bit intimidating to me right now. It soon will not be.
Check out the following websites:
http://www.leerburg.com
http://www.molosserdogs.com
Also, if approached aggressively everyone knows to cease running or biking and stand your ground, right? You don't want to urge their prey drive and it's easier to draw and shoot them in the head - something I came close to doing downtown last year when I was snapped at by a Pit Bulldog mix. He ran out of leash before he could grab my knee...
I drew on the dog as the owner was screaming at the top of his lungs simultaneously trying to get the dog behind him and out of the muzzle of my 1911. Once he had the dog in a bear hug I reholstered and flagged the police who promptly ticketed him.
You've gotta keep your wits about you.
Be safe.