agreed momemtum is the key i drove my last 05 xf all year round til feb 10 2010...........
that day didnt have enough "momentum" to get across a set of 3 tracks(with an incline no less) watched in horror as the burlington express took out my baby at 70 mph
replaced the car,now have 2 sets of tires instead of "all seasons" . ill be running blizzaks next winter.though if hinsdale had cleared the tracks as they should have,it would have never happened