A lot of people who are concerned about getting a DUI are trying to comply with the law. They still want to have a nice night out with friends, but they want to know how many drinks they can have and still be safe to legally drive.
Unfortunately, there is no clear answer to this question.
Some people have heard the old ‘rule of thumb’, that you can have a drink an hour and still drive, or you can have two drinks and still drive.
Neither of these rules is completely accurate.
For most men, if they weigh at least 150 pounds, one or two drinks in the first hour will probably not put them over the limit. However, your blood alcohol level is affected by a number of factors.
These factors can include the rate at which you are absorbing alcohol and the rate at which your body naturally eliminates alcohol.
The rate of elimination of alcohol varies from person to person. It can be anywhere between, on average, 10 to 20 milligrams of alcohol per hour. Some people eliminate alcohol at a higher rate than this and some people at a lower rate.
Your rate of elimination is generally affected by your tolerance to alcohol, in the sense that if you drink often, you are going to have a higher rate of elimination than if you drink less often.
The absorption of alcohol can be impacted by a number of things. Most prominently, whether or not you have food in your stomach. Having food in your stomach can slow the rate of alcohol absorption into the bloodstream, which can then impact what time you reach your peak blood alcohol concentration.
These are not exhaustive factors though, and there are numerous things that can affect the rates at which you absorb or eliminate alcohol. If you go a long period of time without consuming alcohol, or if you go a long period of time drinking regularly, either may have an impact on your alcohol elimination rate.
These things are not constant for any individual person and can change over time depending on various circumstances. The law is based on averages, including the 0.08 standard. But human beings are individuals, and not representative of averages in individual cases.
You may have noticed that in this blog we referred to a male weighing 150 pounds. This is because your gender and your weight directly influence your blood alcohol level, and how much alcohol you can consume while still driving safely.
This means the less you weigh, the less you can drink. If you weigh 300 pounds, you can drink twice as much as a person who weighs 150 pounds. That does not mean that you should drink more because you weigh more, and consider yourself safe to drive. But if you weigh less than 150 pounds, then the rules of thumb are probably not applicable to you.
This means that for many women, in fact likely the majority of women, the two drinks or one drink an hour rule, is not a good rule to abide by.
In addition, although we often refer to the .08 standard for BAC, there are provincial blood alcohol restrictions in place. If you have a Class 7N or an L licence, then you are not allowed to have any alcohol in your system while operating a motor vehicle.
Similarly, under the BC Motor Vehicle Act you can receive a 3-day Immediate Roadside Prohibition for having a Blood Alcohol Level of .05. It takes a lot less alcohol to get to .05 than it does to get to .08. In fact, for a woman, that may be just a single glass of wine.
The answer to the question “how many drinks can I have and still legally drive safely?” is simply not a question that can be answered, because it depends on each individual.
Remember too that the law does not just prohibit you from being over a legal limit, whether it’s provincial or the criminal limit in Canada. It also prohibits you from being impaired by alcohol. Impairment by alcohol is defined in Canadian law as any degree of impairment, even slight. This means that if you are slightly deviated from your norm, as a result of the consumption of alcohol, you could be found guilty of an impaired driving offence.
While you may not feel impaired, the thing about alcohol is that it masks symptoms of impairment, so you do not have the ability to accurately assess your level of impairment, and if you are legally safe to drive.
Alcohol makes you think you are less impaired than you are. So, is it a good idea to drive after having either one or two drinks? Maybe, but maybe not. It all depends on you, your weight, your gender, your tolerance to alcohol, what you have eaten and a whole lot of other factors that you could not possibly consider at the time to determine whether or not it is possible to drive safely.
This is one of the reasons why we think it is important to defend impaired driving cases. The vast majority of people who come to us are attempting to follow rules they have been taught, about how to consume alcohol and drive safely. But they do not understand the science, because the rules are not actually grounded in good scientific practice.
There are people who do not intend to do anything wrong but end up getting caught as a result of the fact that the information that we hear about alcohol consumption and driving is not necessarily accurate. It lulls people into a false sense of confidence that they are following the law when they may in fact not be.
Don’t hesitate to contact our offices if you need help with any DUI-related charges. We are happy to help.