Open differentials are not one-wheel drive. Both wheels transmit the same amount of torque to the road, but when one wheel spins and loses traction (and its ability to transmit torque) the other wheel follows suit. All-wheel drive systems frequently use a set of open differentials connected by another open or limited-slip differential. This means that you can get hopelessly stuck in an all-wheel drive vehicle in the right conditions. I should know, I own one and have gotten stuck.
The biggest difference between those who get stuck and those who don't are the TIRES! I don't care if you have 500 ft/lbs of torque and a fully locked 4WD drivetrain, if you're running slicks you're not going anywhere in the snow. Snow tires are the best investment you can make for winter weather, period.
In practise it is one wheel drive when it is needed most to be two wheels pulling
We do have in law here that we must use winter tires between December-March, but often it is just suicide not to use them from October-November to April.
Our most common winter tire models also have studs, many other countries won't even allow those, don't know how it is in different states in US, your country is difficult as one need to learn over 50 'countries' laws to know what is legal and what not when travelling around US
Maybe you don't have such laws, also maybe winter tires are not common at all there, I know in UK they don't use winter tires very commonly, well don't know about northenders, but those are there up north (sorry).
So we change tires two times a year, there are tight laws about how much thread must be left, how many studs there must be etc. and all this is controlled and checked regularly.
Btw, with better tires, you can get stuck to even more difficult place, not just winter but overall (again talking from off roading)
It's no different from driving around Europe and having to know the various laws in each country. At least in New Jersey, I don't think there are any laws requiring a specific type of tire for the winter. You're free to be an idiot and leave your summer tires on your Corvette. Quite frankly, I think this is the way it should be. The fewer nanny laws, the better. Personal liberties ftw.
I should note that the highways around here get cleared very quickly, though, so as long as it's not snowing, the highways are merely wet. Local side roads can still be pretty nasty, though
We have pretty nice ice coverage on most roads, however they put silly amount of salt to bigger roads if temp just allows it, just stupid, but that is how it is in this socialism nanny country, we sure have many stupid nannying laws here and sometimes I feel that it is required to turn your brains off so surely I think less such laws the better.
Imo, it is bit funny that US is a country, but inside of it there is little countries, so different from what other places has, but maybe not bad at all as then it is easier to fit laws and everything to work well to certain area, but still have support of bigger country.
Maybe EU will be similar to US someday and all countries will be just states, that I would not like to at all really as our country should be independent.
Well, I would like weather from Spain, there is not much snow at least, but that won't work like that wouldn't it
Rough estimate, I would say 25% of people here in the US have winter tires. Fewer still have studded tires. You just dont need them, unless you live in the Rocky or Cascade Mountains, or if you live in Northern New York or Pennsylvania.
For the most part, tire laws vary by region. In the Midwest, where I live, studded tires are frowned upon, and are unneeded because the roads will be clear of snow in 24 hours. We get 4-5 "big" snowstorms here (if you call 8 inches of snow big) and then its all cleared away the next day.
To show you just how big the United States is, I drove from Wisconsin in January to Louisiana in one day. The temperature went from 0 C to 20 C. I go from the arctic freeze to tropics in a matter of hours, all in one country. I think only Russia and China can say the same. It is truly weird.