I got some serious snow testing in this Christmas. The snow started on Christmas Eve morning (12/24, Friday). I left Chicago Executive airport at 11:30AM for Midway airport in a Town Car that I had hired. By the time my friend's flight arrived (only 30 minutes late), all bags were found and we headed for the highway, the snow was really coming down. This was around 2PM. I saw more 2-car collisions by the side of the road on the trip from Midway to Northbrook than I've ever seen. Just about every single one that I saw was a SUV-SUV crash. We got my friend and her luggage inside, and me back to Executive by 3:30. By this time there was roughly 4" of accumulation and 1/2 mile visibility.
The plow guy had been through, leaving a V-shaped patch of snow around my ST, including the unplowed area where previous snowfalls remained. Backing out was no problem, though I saw the traction control light more times that day than during the 9 months since I bought it. I went straight back to my friend's home, and ran errands including driving down an unplowed, unimproved dirt road to the house where her dog was staying.
I kept it in the default "Auto" setting, and had no drama, aside the usual rumble of the front brakes when I made a tight turn in deep snow over a gravel driveway.
Driving home after dark was a whole 'nother deal. The temps had dropped below freezing and the system snowfall was being augmented by lake effect snow. This effectively doubled the snowfall rate to 2" per hour. Most of the salt that had been spread on the main roads in the morning was gone, and replaced by hidden patches of black ice...covered by snow.
My conclusion is that the siping job did make a noticeable difference on both ice and snow. I don't think that they could sipe the asymmetric tread blocks with diagonal grooves in the middle; only the big rectangular blocks were siped. That's OK since the tire patch moves to the outer edge where the sipes are when turning. So when I turned on an icy patch, I ended up mostly in the same lane that I turned from. Others around me ended up 2 or three lanes away on the same turn. Before I got siped, I had to do a lot more wheel turning, throttle induced oversteering and rely more on the computers to keep me in the correct lane.
Note that I'm really talking about right turns. If you make a proper single apex left turn, you have at least 10 times the radius, so it's far easier to turn left in bad weather. The problem is that most US drivers make double apex turns, driving from the end of one center island to the next, making their second apex when they run out of lanes to drive across diagonally. :angry:
