We've all driven past someone who hasn't completely cleared their windshield before driving down the road. Maybe you've done it yourself. But it's never a good idea. In fact, it's one of the 7 sins of winter driving. Here they are from MSN.com:

1. They don't clear the windshield completely.  Driving with a football helmet on would give them a better view. Clear the entire windshield and side and rear windows, and put de-icer in the windshield washer fluid so you can keep it clean as you drive through mud and snow.


2. They don't brush snow off headlights and taillights. Removing snow from windows helps drivers see out, but forgetting the lights doesn't help other drivers see them. Snow from the roof can also cause a problem if it blows onto the windshield of a car behind you.


3. They don't wait for the defogger to work. You've started your car, cleared the snow off and by the time you get in the car to go, you're soaked and your windows steam up. Take the time to let the defrost work so you can see.


4. They drive on the wrong tires. Tires are the only part of your car touching the road -- in effect, they are your car's shoes. Driving in snow on summer-rated tires is like wearing Crocs to run a marathon. For people who don't drive in the snow often, chains are cheap and effective and are sometimes required in mountainous areas.


5. They have all-wheel-drive overconfidence. TV ads promote all-wheel-drive systems and electronic stability control as a worry-free ways to drive in the snow, but the overconfidence they instill can let drivers get too cocky and drive too fast in icy conditions.

You can read about the rest of the sins here.