If we delete the brake function from this model (since all wheels are involved in braking), we can look at the tasks of drive and turn. In front wheel drive, the front wheels are doing both tasks, while the rear wheels are just following along "holding up the back of the car". This can create problems.

Front wheel drive gives the driver several advantages during winter driving conditions. The vehicle seems to give the driver better control in going up hills or on flat surfaces if the road is slick. The reason is because of leverage and weight. With the weight (engine) located over the drive wheels (front), the drive wheels can give much more traction in slick road conditions.

As an example of this, lay your hand on a flat surface like a table and just push your hand across the top. Now, apply a lot of downward pressure (weight) to your hand, and try to move it across the surface. Do you feel the additional traction as a result of the weight pushing down on your hand?

The same is true of the car with front wheel drive; the weight gives the front wheels (drive wheels) more traction. It helps "pull" the car up the hill in slick conditions. However, it also creates a compromising situation. On the other side of every "up the hill" is a "down the hill", and the driver must be very careful while going downhill on slick roads. The weight and leverage (drive) are both in the front; the only thing at the back of the vehicle is what we refer to as "waggle"! This is why so many people start up a hill on a slick road, and think, "Wow! This front wheel drive car is really fantastic" All of the high horsepower rear wheel drive vehicles are over at the side spinning their wheels.

But when they start down the hill, the very thing that helped them go up the hill now becomes a problem. The rear of the vehicle can very easily come around the front and spin out of control. The solution: The driver must be very careful going down the hill, and keep the vehicle slow, straight and balanced. Any side to side dynamics will cause the driver to lose control.

In addition, front wheel drive can present a problem to the driver while accelerating and turning at the same time on a slick road surface.

Let's assume that you are driving a front wheel drive vehicle, slow down as you approach an intersection, and begin to execute a left turn. As you accelerate, because of the slick road surface, the front wheels (drive wheels) begin to spin because you have over-accelerated for the conditions. What will the vehicle now do? Some people expect that the car will spin around; but actually, a front wheel drive car will skid straight ahead off the road because the drive wheels and the turning wheels are the same. Therefore, the car will travel in a straight line as of the moment that traction was lost, and usually straight into a curb or off the road. This is usually a very expensive event for a front wheel drive vehicle.

The solution: the driver must be aware that any spinning of the front wheels will cause a complete loss of steering. This results in absolute "understeer". I. e., the car will not turn as much as the driver desires.

The rear wheel drive vehicle in the same situation will spin around, because the rear wheels (drive wheels) have lost traction; and since the front wheels are turned, the rear of the vehicle will spin around. And it can spin around very quickly!

The biggest problem with rear wheel drive vehicles in slick road conditions is that it is more difficult to "push" the weight up a hill than it is to "pull" the weight up a hill.

All wheel drive (or four wheel drive) would therefore seem to be the perfect solution. This is not necessarily the case, however, as we shall see! The biggest problem with four wheel drive vehicles is that they give many drivers a false sense of confidence. They believe that they "can go anywhere, and at any speed, because they have four wheel drive."

Four wheel drive in slick road conditions will help to propel the vehicle more easily, because it applies the power from the engine to all four tires. This is a more efficient use of power. However, contrary to popular belief ... four wheel drive does not create more adhesion! In fact, in some situations the vehicle actually can experience less traction.

Under acceleration, if the driver over-accelerates and spins the wheels, all four wheels have lost traction. The vehicle is in an absolute skid and will follow the camber of the road surface, usually into a ditch! Also, if the driver uses the back pressure of the engine to attempt to suddenly slow the vehicle, this is essentially the same as locking up the brakes. All four wheels are now out of control because none of the tires are giving rolling traction.

The solution is for the driver to reduce the engine power and bring all wheels back into pace with the engine, and therefore re-establish control of the vehicle. All wheel drive will help the driver, but only if he maintains the overall balance of the vehicle.