Montana is looking at the possibility of raising its daytime interstate speed limit to 85 MPH

I agree. We just finished a bout with freezing rain, which is just another variation with water supplied by rain drops suddenly freezing. The idea that it’s called black ice, at least around here is, the hot top roads at night are black and the road takes on a black sheen. I know what you are saying. Nothing moves and even the crown of the roads suddenly becomes hazard to deal with. We were caught on one after a three man refereeing game and it took us six hours to travel the 60 miles home. We went into the ditch a dozen plus times but were traveling so slowly, it was like slow motion. With three adult males, we just slide the compact sideways back into the middle of the road then proceeded at a blistering 15 mph until the next curve where it then happened again. Funny, as many cars that there were off the road, because everything was ice, no one was seriously hurt. No one could go fast enough. I am hoping that the technology of determining the surface make up and temperature “down the road” ahead of us is in the future of all cars.

In those times of transition temperatures, I watch the temperature reading pretty close. If it gets to 31 or 32, I know ice may be forming. With the cars now, its actually pretty hard to judge how slippery it is unless you brake a little or hit the gas and see if the wheel spins.

Tires with retractable studs?
I have no idea how to do that, but nobody knew how to make a 3D printer either.

@circuitsmith Check this out: