I was going to mention Montana. There are certainly places in this world where raising the speed limits would be totally safe and save lives - and also a precious little thing called time which some need to earn money and enjoy life.  
There are many more important laws and driving habits than just speed.  I’m willing to let someone who follows all the rules set the speed limit, as this person would understand what is really important.  Other than that though I prefer to drive at a safe speed of my choosing -  thank you Mike!!!!!!  Saved me two tickets last week alone. Hundreds over many many years of proud Valentine ownership.  The only accessory I ever add to all my cars. I protect it like my Rolex.