Posi, good for icy roads?

Had the rear of my Dart up on stands and decided to check the gear ratio. Got just under 3 complete revolutions of the drive shaft to 1 tire revolution. So would that make it a 2:?? to 1 gear ratio? Also, both rear tires turn the same direction when I spun one of them so it seems it is a posi (sorry don't know the Mopar term for a positrac), are these very safe to drive in snow and icy conditions? I've heard two schools of thought on this subject?
Author: admin