So I've been driving in snow for 20 years. I realized this recently while watching people who obviously haven't been driving in snow that long do dumb things.
Living in a college town, there are a lot of people from all over the country and the world who come here. Many have never seen snow before. Some come from places that shut down if it snows. Yes, some come from snowier places than Chicago, but it doesn't take many inexperienced drivers to cause problems.
First, ice is the great equalizer. It doesn't care what you are driving, whether or not you have 4WD or AWD, ABS, traction control.... If you hit ice, you will likely slide. Knowing what to do is the key. And trying to drive such that you have as much control as possible is a must.
So, a few rules for driving in snow.
First, turn on your headlights! Headlights serve TWO purposes: so you can see and also so you can be SEEN. Using your headlights means oncoming traffic can see you better. They also mean cars behind you can see your taillights, which are not on if you have daytime running lights, without you needing to brake. Being visible is important; it gives you and other drivers (don't forget those other drivers!) more time to react. If you don't believe me, pay attention next time it is raining or snowing to which cars you can easily see. It'll be the ones with headlights.
Second, don't drive like the streets are dry. They aren't. They will be slick. Being conscious of the conditions is crucial. Sometimes a little caution is necessary, sometimes a lot. How many times have you seen 4WD SUVs in ditches on the side of the road? As the car commercial (can't remember which brand) says, safety features are not a substitute for safe driving practices.
So what are some safe driving practices? Don't tailgate. Keep a larger following distance than you normally would. Leave plenty of time to brake and accelerate slowly. Take it easy. It's better to be late than dead. Pay attention to other traffic. Use your signals both to turn and to change lanes. You may know where you're going, but no one else does.
If you do skid, steer into the skid. Now, this never made sense to me until I figured out what it means. Steer in the direction you want the car to go, but do it gently. Once you regain traction, you don't want to overcorrect and end up skidding the other way!
If your car is light, you may want to put bags of sand or litter in the trunk over the rear tires to help keep traction. If you get stuck, you can always pour the sand or litter on the road under your wheels.
If you don't have experience on snow, find an empty parking lot and drive around. Do some donuts until you learn how to control a skid.
If you can, make sure you have good tires and fresh brakes. Balding tires with no traction are exactly what you don't want on a slick road.
Okay, I'll step off my soapbox now. But please be safe.