All Wheel Drive ... Good or Bad?

Winter has finally hit up here in the cold white north.  Cold temperatures, snow, and yes ... bad roads.  This last week the talk among commuters around the water cooler has been how long it's taken them to get to work and all the cars in the ditches.  And yes, many comments like "I'm so glad I have All Wheel Drive" or "I really wish I had All Wheel Drive" are heard from afar.  But really, is AWD really what it's cracked up to be?  Should you trade in your Front Wheel Drive for a new 4x4 to get through this winter?  This article will discuss if AWD is really going to make you safer on the roads.

I have two vehicles.  I have a Front Wheel Drive Mazda 6 with a 5-speed manual transmission, and an All Whee Drive Lexus RX330 with an automatic transmission.  Both cars are equipped with winter tires in the cold months of the year.  Now, when asked, most people would expect me to say that I would rather drive the AWD SUV through the winter.  They are often surprised to learn that I strongly favor the Front Wheel Drive car in almost all conditions.


But why would this be?  First, let's explore what AWD does well.

All Wheel Drive is great in deep snow.  If you live in the country and have a long driveway, or you live in a subdivision that doesn't get plowed, then AWD is an asset for the few days after a deep snowfall, or until the snow gets packed down.  The morning after a heavy snowfall, having the confidence to drive through the fresh powder is definitely a benefit.

All Wheel Drive is also a benefit when accelerating.  This means that AWD is definitely more fun to drive in the winter.  And if beating everyone else off the line when the light turns green is your thing, AWD is for you.


However, none of this makes your car any safer.  As soon as you get out of your unplowed subdivision and onto the plowed roads, there are many more drawbacks that are often overlooked.  Now, let's explore what AWD does poorly

First, braking and cornering...  "But wait, I thought AWD handles better!"  This is a misconception.  The ONLY time AWD handles better is when your foot is on the gas.  It has zero impact when you are braking, and if you are trying to accelerate around a corner when you are already skidding, you need to go back to driving school.  Consider the "Friction Circle."  If you aren't familiar with the Friction Circle, you can read about it here.  Basically, if you start to skid, you need to reduce the load on your tires by either straightening your wheels, or braking/accelerating less.  Getting out of a skid by relying on AWD doesn't work in most cases.

In fact, a few years ago I took a Subaru Impreza for a test drive on an empty icy road.  I was expecting the AWD system in that car to impress me.  It didn't.  In a Front Wheel Drive car, when the wheels start to spin, you expect the car to understeer.  You can instinctively react to compensate.  With a Rear Wheel Drive car, you expect the car to oversteer.  You can instinctively react to compensate.  But with that AWD car that day, the car was spiratic.  When the wheels started to spin, sometimes it would oversteer, sometimes it would understeer, and sometimes the car would literally just go sideways as all four wheels fought to get traction.  In an emergency driving situation, this unpredictability is a huge concern.

Next, let's compare two identical vehicles, one with AWD and one without, since many cars and SUVs are available as a 2 or 4 wheel drive variant.  An AWD system is heavy and adds a lot of weight to the car.  So, the vehicle with AWD will be considerably heavier than the one without.  On slippery roads, weight matters.  As we've all learned in high school physics, the heavier the object, the more momentum it has, and the more force required to effect its speed or direction.  When you have to stop fast, you want the car with the least momentum.  When you have to react fast to avoid a collision, you want the car with the least momentum that needs to be overcome.  Period.

Next let's discuss the psychological side.  AWD gives you a false sense of confidence on the roads.  Many drivers get it into their heads that, if the car can accelerate faster, then it can brake faster too.  This is a huge problem, especially on highways.  Just because you can get up to highway speeds faster on an AWD vehicle, drivers often also feel they can switch lanes faster and hold higher speeds as well.  This is absolutely not true, and the reason why there are more AWD and 4x4 vehicles in the ditches along major highways than 2WD cars.  This false sense of confidence catches people off guard all the time.  All Wheel Drive causes more accidents than it prevents.


So what is the alternative?  What is better than AWD?  Simple.  A good set of winter tires...

Here is the problem with today's cars.  More and more cars are coming with "Performance All-Season Tires".  People typically see the "Performance" part and buy into the marketing thinking it means better.  When in reality, these tires are nearly as terrible as summer tires when the temperature drops below freezing.

Performance All-Season tires are designed to withstand high speeds, and are manufactured using a harder rubber compound.  When the temperature drops, this hard rubber no longer holds the road and makes driving in the winter dangerous.  Winter tires are designed with a much softer rubber compound that still sticks to the road when the temperature drops.  If you are still running all-seasons on your vehicle, especially "performance" all-seasons and you are concerned about your safety in the winter ... go buy winter tires.  Now.  The investment in your safety and your family's safety, as well as the safety of everyone else on the road, is well worth the expense.


Conclusion ... Although AWD is nice to have and is a lot of fun to drive on bad roads (if you like driving on bad roads), it does NOT make you any safer and it is NOT a replacement for a good set of winter tires.  So know your car, and don't fall into the trap of thinking that AWD is a necessary part of winter driving.