I hear what you're saying but speed limits, IMO, are patent BS as currently set. Speed limits haven't been raised since the 60's and cars today are much safer and higher performing than they were then. The quality difference in tires alone is huge.
I hear what you're saying too, but since I feel that most gun laws are patently BS and do not accomplish their aim, should we simply ignore them? Are laws to be subject to an individual reasonability test? If so, I've got a lot more to do tomorrow than I had planned.
Here in MA, we've decided not to have real driver training, to have a ridiculously easy driving test, and to not enforce most traffic laws (except for speeding). So as I said, I don't think speed differential is the cause of the accidents; instead, the cause is all other stupid stuff people do on the roads.