All objective studies have concluded that neither speed limits nor actual speeds at the levels talked about here have anything to do with changes in highway death rates. Modern cars can be driven quite safely on modern highways at speeds of 80 or 85 mph. The only variable conclusively linked to the highway death rate is miles traveled. When we drive more miles, there are more highway fatalities. DUH!
Obviously, there are bad things drivers do that increase the risk of injury or death for themselves and others -- driving impaired (by alchohol, drugs and cell phones), driving at speeds significantly above or below the rate of traffic flow on that road at that time, driving on worn or under-inflated tires, weaving in and out of traffic at high speed, driving at speeds unsafe for road conditions, just to cite a few examples.
However, the lazy-assed state troopers who sit on the side of the road on clear sunny days (God forbid they should spoil the crease on those trousers by doing it in the rain) blasting away with their radar guns and lasers are doing precisely nothing about any of this. They are just making the insurance companies happy, by giving them an excuse to raise rates, and keeping the state coffers full. Traffic safety is their justification, not their concern.
These are the people who really burn me up. You know, the guys who have to go (at least) 20 mph over the speed limit and continually weave in and out of traffic, cutting people off without using a turn signal so that they don't have to suffer the annoyance of driving at reasonable speeds. Either that or they ride right up on your ass at said 20 mph+ above the speed limit speed trying to force you over a lane. Never mind that there are other cars immediately in front of you, so you couldn't go any faster even if you wanted to.
Not only that, but the bastards are really making it more dangerous for the rest of us by doing so.
Whenever a driver sees Barney sitting alongside a road, most instinctively hit their breaks, since they don't know exactly how fast they are going relative to the limit. This causes lots of problems, not the least of which is causing cars to bunch up together.