[/quot
Ever try to control a vehicle going down hill on a 10% grade on black ice and not hit the
vehicle stopped in front of you?  Can't use brakes or a transmission smarter than you designed
for maximum fuel efficiency.
Try it sometime on the wolds highest mountain/volcano.

Anecdote for you guys,  CFHT rolled their suburban off the road in black ice.
Rescuers had to cut off the hair of one of the occupants as the vehicle deformed
so much as it rolled her hair went out the door and they couldn't open the door when it stopped.
Only way to get her out.
She was un harmed but it took a while for hair to get back to her normal habit.