Greatly exacerbated by low profile, wide tyres, on the wrong compound. If you want ultimate traction, an old mini on narrow tyres works best. Wide tyres work great in the dry, but you need a small contact patch and lots of weight over the driven wheels in snow conditions. Event 4wd rally cars use 4inch tyres in heavy snow, not 8 inch slicks. A friend of mine works in the motor industry reminds me that standard tyres only work well with road surface temperatures above 7 deg C. but when the average road surface temperature is below 7 degrees C - and in the Highlands of Scotland that's about 8 months out of 12, winter or cross climate tyres perform better.
Entertaining rants on here though - sifting the facts from the misinformation.. I understood emissions for manufacture greatly exceeded emissions from use - irrespective of fuel system - so it makes more sense to use existing vehicles for longer. WHY did I sell my 1981 mini? DOH.