I say the 10 car lengths because one has to be able to stop in snow covered roads in time!
Yes, and there are idiots who still think they can stop on a dime in accumulating snow!
I was thinking of the snowy night I was driving upstate along Cat Hollow, a 2-lane county road, about a quarter mile or so from a T intersection with State Route 30, where one's choices are to stop and then make a left or right on Route 30,,,, or else lol "just keep going"... and land in the Pepacton Reservoir.
It was along my regular commute upstate on weekends, and I had been keeping a good 20 car lengths back from the pickup truck in front of me as we approached that intersection. But to my dismay I suddenly saw another vehicle's lights looming in my rear view. I slowed down even more and edged slightly right to give him room to go around me despite our being in a no-passing zone. He did impatiently swing out and around --so at least he didn't rear-end my car-- but he then charged on until he was tailgating the pickup, who apparently also realized what was about to happen so he moved left into the empty oncoming lane and came to a full stop, at which point both he and I got to witness the reckless driver jam on his brakes, slide through what was supposed to be a full stop, meanwhile doing a series of 360s, with each one advancing a bit more across the state road while veering a bit north.
I'm not sure that guy even realized there was a reservoir on the other side of the guardrail that he finally caromed off as he emerged from the spin, then tried to back up, apparently meaning to head south but couldn't get traction and so just continued north instead. No clue if the guy knew either how far it would be along Route 30 north before he could turn around. I felt blessed that he either didn't know where he was heading, or that he did but was not going where I was, or at least not without making some interesting maneuvers to turn around on an ill-plowed road at that hour.
As the pickup driver and and I slowly resumed our respective journeys south on 30, I saw him briefly take his hands off the wheel and give a palms-up shrug, then wave in the mirror to me. I nodded and returned the wave and then hung back to get my 20 car lengths behind him. I was praying that the idiot heading north hadn't decided to make a U-turn and come barreling down Route 30 to fill in that gap AGAIN as the pickup driver and I both slowed down once more while approaching a village.
Fortunately the only other drivers I saw on that trip acted like they knew how to drive in the snow that accumulates on the road before the plows make another round. That other car driver was really really reckless.. and lucky! It was before the time of cell phones, so it would have taken either the pickup driver or me a good ten minutes to get down to the village and a substation of the state troopers to report the incident if that guy's car had breached the guardrail. There's nothing on the other side but a steep cliff down to the inlet of a creek to the reservoir.