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4WD/AWD safety - Is 4WD/AWD safer on snow and ice?
I am assuming that you want 4WD/AWD for safety on snow and ice. 4WD/AWD systems provide some but not much added safety! Only the convenience, that you don't have spinning tires when starting - or the convenience to get started where a 2WD would not be able to get going. Or the convenience to get up a snowy pass without spinning tires or without mounting chains.
However, once moving the physics for all vehicles are equal. 1WD, 2WD, 4WD, 6WD etc.
All motor vehicles need traction for safe steering - 4WD/AWD does not provide extra traction for steering.
All cars need traction for safe braking - 4WD/AWD does not provide extra traction for braking.
In that sense 2WD is "safer" - it leaves you stranded early and keeps you out of trouble. The trouble only 4WD/AWD owners might get into.
The problem is, that most 4WD/AWD owners think they operate a safer system. Once moving (on any slippery stuff) they drive faster than they should and not as carefully and slowly as they would in a 2WD. Much more 4WD vehicles are involved in accidents on snow and ice than 2WD.
Since snow and ice provide only marginal traction (so marginal that you need 4WD/AWD to start moving) and not enough lateral force can be created to support the tires during a turn, they slip sideways and the vehicle falls off the road. 4WD does not prevent that. 4WD is not involved in the steering part of driving.
Since snow and ice provide only marginal traction (so marginal that you need 4WD to start moving) not enough traction is available for safely stopping the car. Neither ABS nor 4WD helps you to stop the car. 4WD is not involved in the braking part of driving at all and ABS only keeps the tires from locking up. Locking or not locking has almost no influence on the stopping distance.
 And by the way, when you own a part time 4WD vehicle, ABS does not even work anymore when you shift into 4WD.
Here are the things that help on snow and ice:
4WD to get going
patience
good snow tires
patience
chains are better (even on a 4WD/AWD)
patience
the wisdom to know when slippery is too slippery
patience.
One feature that really adds some safety to driving on snow and ice is ESP. A stability program available on some vehicles that counteracts loss of control. It almost completely eliminates roll overs.
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Comments
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01-29-05
At 58 years of age--i thought i was educated on "4 wheel drive"......I recently attempted to explain to my daughters the dangers of being overconfident in driving in snow/ice with their "4 wheel drives" and realized i "just knew stuff" and couldn't explain it well. What a help your site is!!!!....... Thank you very much for providing this information in such a clear format. I appreciate the time and trouble you have invested .........Cordially, Charles
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4x4 driving tips