Bans? Absolutely not! The image of these dogs being any different from any other dog breed is a myth. I've been around hundreds, if not thousands of these dogs as a volunteer and board member of our local shelter. There are definitely some nasty individual animals, but that's true with every breed (and mixed breeds too!) The overwhelming majority of Pits are extremely nice dogs. The claim that they are more dominant or more difficult to train than any other dog is absolute hogwash. You want a dog that's difficult to train get a Basenji. A Pit Bull is no more difficult to train than any average dog, though as with any breed some individuals are easier to work with than others. German Shepards have the strongest bite strength ever measured in domestic dogs, with wolves measured at roughly 30% stronger. By the way, Pit Bulls DO NOT lock their jaws when they bite. They are terriers, a group in which the tendency to grab, hang on, and shake has been accented through selective breeding, but they can let go just as easily as any other dog. Any law or restriction that is breed specific is naive and ill conceived. (Weight restrictions in apartments are an entirely different matter. By the way, 35 pounds IS considered a small dog on some charts. It just depends on who's chart you look at.)
The AVMA (American Veterinary Medical Association), HSUS (Humane Society of the United States), AKC (American Kennel Club) and many other groups are on record strongly opposing breed specific regulations. Pennsylvania even passed a law making it illegal for local communities to establish breed specific regulations.
Since reporting requirements and standards vary greatly there are no reliable numbers for dog bites. Legal firms which sue people over bites claim numbers so high that every dog in the country would have to bite someone once every two or three years to actually be accurate, which is clearly preposterous. The NAIA (National Animal Interest Alliance) would have you believe that there are almost no bites, equally a preposterous. Dog bites, and serious bites, do happen but occur across all breeds.
In the mid '90s a study was published in JAMA (Journal of the American Medical Association) which presented an evaluation of deaths by dog bite over a 10 year period (deaths are a required reportable incident.) With approximately 250 incidents over that period (against roughly 70 MILLION dogs) the claim was made that specific breeds were more highly represented and therefore were more dangerous. The AVMA and AKC sent strong responses, including very real criticism of scientific and statistical methods and conclusions reached. The writers actually redid their evaluation, shifting the data collection period forward 5 years and found a different set of breeds represented in fatal attacks. In the end they withdrew their original conclusions (admitted the original ones were mistakes) and agreed with the AVMA that definition of dangerous animals should be based on the behavior of the individual animal and not breed. Unfortunately severe damage was done and many insurance companies use that original (and discredited) paper to define dangerous breeds when establishing home insurance. If you ever see a restriction that defines "Siberian Husky" as a dangerous animal you'll know they're using that discredited paper.
Another major part of the problem is the press. Often attacks are attributed to Pit Bulls, even when the animal involved is nothing close. Our worst attack in recent history was about 8 years ago. A dog attacked a man and tore the scalp completely off the top of his head, among other serious injuries (the man survived.) The paper naturally reported it was a Pit Bull, but the dog was in fact a fully pedigreed Great Dane (and all the Animal Control paperwork indicated as such.) We had another case when a dog was running around a local playground and keeping the grownups away from the kids (though several kids were actually playing with the dog.) The paper again reported "Pit Bull", and reported the dog was attacking people (though it wasn't) though the dog was clearly a Rhodesian Ridgeback. Another case was reported as two Pit Bulls attacking a young teenage boy, but these were a Labrador Retriever and a Lab/Golden mix. I saw every one of these dogs up close and there was absolutely NO way they could have been mistaken for Pit Bulls.
As to the German laws that highly restrict Pits, German Shepards have an history of causing more injuries and more serious injuries in Germany than Pits. Yet a couple of highly publicized cases and bad press and the government officials acted in a knee jerk fashion. (They'll never put a restriction on their national dog.) The "temperament test" that's given to any existing animal (no new one's are allowed) basically have the "tester" pestering, taunting, teasing, and torturing the dog for up to three hours. Even if the dog never shows an aggressive act the "tester" will usually fail the animal and claim it showed "potential" to act up. These laws have received considerable condemnation from veterinary groups, humane societies, and other countries as being excessive and ill conceived.
As for temperament tests in general, particularly at shelters, this whole area is highly controversial. I have no confidence in the evaluation of an animal done by someone that's had 4 hours of training and now is suddenly an expert on dog behavior. This is a whole other discussion, so I'll not go into it any more here.
Any regulation that would require training for the person would be difficult to defend on a Constitutional ground. Breed bans have not stood up to legal challenges, but local officials usually realized that most individuals do not have the resources to go through the lengthy (and expensive) process of challenging these laws. Then again, as I said above, these dogs are really no different than any other. They were, for a time, the popular dog among drug dealers and the types who will intentionally make a dog aggressive and nasty. Yet, they are only the latest breed to be used as such, it was German Shepards, then Dobermans, then Rottweilers, then Pits, and is now moving away from Pits to larger breeds derived from Mastiffs such as Dogo Argintino and Presa Canario.
Pit Bulls are believed to be the most common dog in the United States. Most are wonderful animals. Remember, Petey from Little Rascals/Our Gang fame was a Pit Bull.