Wow... i'm amazed that anandtech - supposedly a place full of smart people - is actually populated by dozens of white-knuckled kia drivers who freak out at anything going faster than 50mph. Seriously, cars were safely doing 100+ mph ONE HUNDRED YEARS AGO. Now add on 10 decades worth of safety engineering, and you're basically a retard to think that 55/65 mph is the fastest that people can safely drive.
The problem lies with people who are absolutely clueless about how to handle that 3000 lb piece of equipment they're in control of. Driver training in this country is horrible... even when i was getting my license for the first time a few years back, i remember thinking to myself, "lol, this is it??" I got my pilot's license before my car license, and i was seriously amazed at how easy it was to get permission to drive around narrow, crowded, heavily populated streets in a giant, steel battering ram compared to the training required for a pilots license. I mean, in the air, the chances of you plowing into a pedestrian or running off the road are decidedly slim... yet the time spent training a new pilot is 1000 times greater than a new driver.
Point being, cars and roads are more than capable of safely transporting people at (MUCH) higher speeds, but to do this you need to revamp the driver training in this country, and make it something that has to be renewed every couple years. Make driving laws stricter, and you won't see some moron cruising along at 50 in a 65 with their cell phone to their ear, because that kind of inattentive retard wouldn't even qualify for a license.
And now that you've disqualified 75% of the mentally challenged citizens of this country from clogging up the highways, you've got a nice big population who will be wrangling for a better public transportation system. i.e., greener, more efficient transportation. Not to mention the few competent people left on the roads will actually be able to get from point A to point B at a reasonable speed without worrying if Mr. and Mrs. "this car climbed mt washington!!1" are going to absent-mindedly wander into your lane while you're passing them.