All dogs are potentially dangerous, the easiest solution would be to pass a law that all dogs, when out in the public domain, must be muzzled. Break the law and the dog is destroyed- harsh I know but it would solve the problem.
Nah, you don't hear any stories of people being mauled to death by a poodle, a spaniel or a Labrador etc...
Every dog breed has been created by humans. They all retain the instincts of that breed design. These pit bull types are bred to fight bulls. Bred to bite into a much larger animal, and bring it down, even while being kicked and stamped on, they will not let go. They will fight to the death.
Now read back over that last paragraph and imagine your kids playing in the park and some 10 stone scallywag, strutting by with an XL bully that could over power him in a nano second. It's not even his dog, he's minding it for his mates sisters boyfriend. Yet here we are.
I think the only way to go with this is dog licenses for anyone with a dog. And a ban on dangerous breeds that kill people. If the licenses doesn't put them off, then jailtime or big fines for having a banned dog should deter them.
If there's one thing that any dog owner knows, is that you have to go outside with them. They have to walk/run/piss and shit. If you are seen outside with a banned dog, they'll catch you.