After an evening out at a restaurant or bar, people may hesitate a moment before getting behind the wheel, weighing whether they are sober enough to drive home safely.
Although it may seem like a straightforward question, there are a number of reasons why those who have consumed alcohol are not in a position to judge whether they should drive.
Counting the number of drinks
According to the National Institutes of Health, the U.S. standard drink contains 14 grams or 0.6 ounces of pure alcohol. What that looks like when the bartender or waiter hands it over can vary widely, and it can be hard to tell if that glass has 5 ounces of wine in it, if the cocktail has more alcohol than mixer in it or if the beer has a percentage of alcohol greater than the standard 5%.
Not only do the drinks vary in alcohol content, but bodies vary in how they metabolize it. Size, weight, gender, health, food intake, water intake and other factors can make a big difference in how one drink affects blood alcohol content.
Gauging by how they feel
Some prefer to determine how sober they are by how they feel. The irony is that alcohol can make a person feel more confident about driving safely while also compromising the actual ability to drive.
According to American Addiction Centers, with a BAC of 0.01% to 0.05%, people do not usually appear intoxicated, although they may have impaired judgment and reaction time. With a BAC between 0.03% and 0.12%, euphoria is common. This high can mask other effects such as loss of coordination and delayed motor responses.
Because it is difficult to assess intake or think clearly after drinking, planning a ride home before the night begins is an easier way to avoid any problems.