Transcript: Here's a sobering thought: In the USA, every thirty minutes someone is killed in an alcohol-related motor vehicle accident. What's even more frightening is that the majority of those deaths occur when someone between 18- and 20-years-old is behind the wheel. So drinking and driving is clearly a terrible idea. But it's important to understand why. Alcohol is a depressant, and, as such, it can have a serious impact on your driving capabilities. For starters, alcohol causes your eye muscles to function more slowly.  This means that it becomes difficult to track objects properly, and it impairs your night vision.  Also, because alcohol is a depressant, it causes you to react more slowly, to say, a person in the middle of the road.  In a similar vein, it causes your coordination to decrease, meaning that your brain may want to hit the brake, but your foot will be too slow to do so in time. And, as you may already know, alcohol can cause you to nod off and lose concentration. These are just a few of the reasons why you should not drink and drive.You might be surprised how quickly you will hit your BAL number. A 120-pound woman, for example, will have a BAL of .08 after just two drinks over the course of an hour. A 180-pound man will hit the same blood-alcohol level around his fourth drink during an hour. And remember that a “drink” equals one 12-ounce beer, one 5-ounce glass of wine or a single ounce of liquor-amounts much smaller than what you're probably used to consuming! With this information at your fingertips, it just makes sense to call a cab or hand over your keys to a truly sober friend.