As far as that test was concerned, I think they wasted their time with "all-season" tires.  I can tell by looking at the tread that "all-seasons" are worthless.  I prefer "all-terrains" for my F250 (with heavy diesel engine), with it's more aggressive side-to-side tread pattern. We don't even use studs on my wife's Saabaru  (a Saab with the Subaru engine/drivetrain) and we get by fine with carefully chosen tires.

Every 4 to 6 years, "outlawing studs" seems to get on the ballot.  It fails miserably Every Single Time.  I may not use them, but I don't want to see them outlawed.