winter 2010 in nyc was no joke,i was literally stranded in the snow and ice and those all season 20in tires werent cutting it, after about 8 hours i got free (1 of my not so good days) as soon as i unfroze my feet i called tire rack for winter tires and the only ones available were bridgestone blizzacks in my size, (i didnt want to go smaller which actually helps in snow) the difference between them is nite and day! winter tires are all siped if im correct but the also have a much softer compound so it doesnt freeze up in colder climate, im assuming both are contributing factors. i swear in the snow i was able to do things and drive through things that i couldnt before on the flip side if there wasnt snow and ice on the ground the tire noise was extremely loud and it handled horribly in my opinion, very very sloppy!! i never heard of siping being offered on tires tho and because i have tires specifically for winter i wouldnt try it