There are few subjects that are surrounded by more misinformation than drinking and driving. Perhaps because of wishful thinking, people tend to believe some really ridiculous stuff. Here are just some of the myths about the subject:
1. Alcohol is a stimulant.
Wrong. Alcohol is a central nervous system depressant. However, one of the things it depresses is the activity of the brain—particularly the centers of impulse control. As a result, intoxicated people frequently engage in activities which they would avoid while sober, but not because they are stimulated, but because their higher brain is asleep at the switch.
2. Alcohol on the breath is a reliable sign of impairment.
Nope. Drinking alcohol (ethanol) has no smell. The distinctive “alcoholic beverage” smell is from the byproducts of the fermentation process, known as “congeners.” However, many beverages are engineered to minimize the alcohol while leaving in the congeners. These products, like O'Douls or other near-beers, will give the breath the smell of alcohol even if the drinker has no alcohol on board at all.
Even experienced police officers could not tell the level of impairment from the smell of alcoholic beverage on the breath. In laboratory research, the officers estimates of alcohol levels from the odor of alcohol were no more accurate than random guesses. Moscowitz, H., Burns, M. & Ferguson, S. Police officers' detection of breath odors from alcohol ingestion, Accident Analysis and Prevention, 1999 (May), 31(3), 175 180.
3. Even one drink is enough to increase your chance of an accident.
This is a myth which has been dispelled by nearly every field study. In fact, the research indicates that for the first drink or two, your chances of being in a crash are actually reduced below the base rate for totally sober drivers. No one knows exactly why this is so, but the effect, known as the “Grand Rapids Dip” for the study in which it first appeared, has recurred every time researchers have done large-scale field studies of drinking and crashes. It is certainly true that your odds of a crash increase exponentially after more than two drinks, but we shouldn't gild the lily. The truth is good enough. One drink WILL NOT increase the danger of an accident, unless you have some other problem with your driving.
4. Half of all fatalities are caused by drunk drivers.
This one is hard to evaluate, because the U.S. government does not keep track of accidents which are “caused” by alcohol. For bureaucratic reasons, the government keeps track only of “alcohol-related” crashes. A crash is “alcohol-related” if any occupant of any vehicle (even a passenger) has any measurable level of alcohol in his system. You might ask, “What is the purpose of even keeping that statistic?” We can't figure it out either.
It's an “alcohol-related accident” if a designated driver who has a drinker in the back seat gets run into by another car while standing still. In fact, it appears that about one in seven traffic fatalities can be attributed in some way to alcohol. That's too many, but we shouldn't lie to ourselves to make it seem worse.
5. Always stay away from hard liquor.
It is a common misconception that if you're only drinking beer, you won't get overly impaired. But surprisingly enough, the amount of alcohol in a 12 ounce beer is about the same as there is in a normal glass of wine or a 1.25 ounce of 80-proof liquor. There's a good reason for that, too. Historically, the size of a “serving” of an alcoholic drink was established by its alcohol load. So it's not really a surprise that the number of rounds is more important than what drink you are imbibing.
6. Rolling down my car window will sober me up.
A little cool air on a winter evening will wake you up, and it doesn't hurt to be wide awake when you are driving, or if you are submitting to a DUI investigation. It won't sober you up, but many of the “clues” of impairment that police are taught to look for are also clues of being sleepy.
7. A penny under your tongue will fool the breath test machine.
This is just an insane piece of magical thinking. It is hard to even fathom where this myth started, since it is entirely divorced from reality. There ARE ways to minimize the breath test reading (See "The 3/2 Rule"), but this isn't one of them. It actually doesn't work for a second reason (besides the fact that it's nuts): Part of the police protocol for performing a breath test involves checking your mouth to make sure that there are no foreign materials in there. After all, an undetected wad of tobacco will act like a sponge, holding unabsorbed alcohol and releasing it into the breath machine. That will blow the results off the charts!
The breath testing process is a scientific process. It is poorly run, and badly monitored, but it is scientific if it's done right. The key to not getting falsely convicted is to understand and respect the science.