Originally Posted By: tanstaafl.

4x4's accelerate much better than two wheel drive vehicles in slippery conditions, giving a feeling of invincibility. Their stopping ability is no better and frequently worse*. Needless to say it is stopping that keeps you out of ditches.

It isn't just the stopping that keeps you out of the ditch. It is also the ability to recover from slides and take avoiding action before you reach the ditch.
_________________________
Remind me to change my signature to something more interesting someday