When the police pull a driver over who then fails a subsequent breath test, it can often come as a surprise to the driver. They probably know they have consumed alcohol but might believe they were under the limit when they got behind the wheel and still are.
People often try to gauge how much alcohol they can have before driving, but this is problematic for two reasons. Firstly, even a small amount of alcohol impairs a person’s ability to drive safely, making a crash and injury or death more likely. Secondly, people are notoriously bad at judging how much they have drunk.
People tend to underestimate
Studies have found that people often underestimate how drunk they are. They believe their blood alcohol level is lower than it is. That could be a problem, especially for drivers who aim to consume the maximum they think they can legally get away with rather than stopping well before they get there.
Blood alcohol level is also hard to estimate at the best of times. Two people could drink the exact same drinks as each other, and one could have a higher blood alcohol level (BAC) than the other. Or, one driver could drink the same amount on three different days and emerge with a different BAC level on each. There are so many things that can affect a reading besides the quantity of alcohol consumed, and while these things might not affect it much, it can be enough to mark the difference between passing and failing a BAC test.
Remember, too, that the police might still charge you even if you have not reached the BAC limit if they believe your driving showed signs of alcohol impairment.
The safest way to handle alcohol and driving is to keep them entirely separate. If you want to drink, don’t drive, and if you want to drive, don’t drink. If you do try to mix the two and your careful calculations prove wrong, then you may want help to examine your legal options.