must full time 4wd
The most safe on icy road is full time 4wd with limited-slip central differential.
VW Touareg, Audi Q5, MB GLK.Subaru with manual transmission..
other full time 4wd without limited-slip central differential.
Jeep grand Cherokee, BMW X3,
Stay away from those auto on/off 4WD. It is more dangerous than FWD on icy road.