In the late 1960's I worked in Northeast Montana, driving several hundred miles each day. The speed limits then were "Resonable and Prudent." We would routinely drive 75 to 80 on most roads where conditions allowed it. I only saw one accident in two years and it was more alcohol related than speed.
It's nuts and will be much more deadly and destructive until they also decrease the reaction time of the drivers involved.
The National average for reaction time(which is decided to be 3/4 of a second from the time you visualize a collision about to occur and you are able to get your foot off the accelator and head for the brake pedal(not contact the brake but head for it with your foot)anyone like to hazard a guess on how many feet you will travel at even(example)70 mph, how about 270 feet with no assist from your brakes and if you are following closer than what is reasonably considered at highway speeds and conditions add another 1/2 second to you reaction time figuring the guy directly ahead of you on who you are concentrating as one who presents the greatest immediate danger to you and your vehicle has akready used up 3/4 second of your 3/4 second time you need to lessen the rear end impact you are fixing to experience without an noticeable reduction in you headlong rush toward the little bracket this truck's trailer has welded at the rearend of the trailer to keep your vehicle from running merrily into and under(likely the last sound you will remember and sight you will see will be grinding metal, screeching tires, flying glass and the windshield with your head embedded in it and all this riveted into your memory if you have any left....) "KABOOM"!!