Tejon pass, also known as the grapevine (for better reasons many years ago than now). 6 and 8 lanes of highway with people driving with their head up their butt, I crossed it a couple of years ago in a hard rain and witnessed several accidents, mostly single car caused by driving way too fast for the conditions and losing control on flooded pavement. You can imagine what would happen with snow and icy conditions.

I learn something every day, and a lot of times it's that what I learned the day before was wrong