According to your estimation, driving 6 mph over the limit is driving too fast. So if the speed limit is 45mph & you're driving 51 mph, you're driving too fast. So anytime you drive faster then 45mph, no matter what the speed limit is (55, 65 or 75mph), you're driving too fast. The only ones who will benefit from the black box is the insurance companies & government. I don't ever see the insurance companies lowering their prices to make that much difference to the insured & as for the government, it is only another way that big brother is watching & controlling your life.