Knowing Your Limit: A Guide to Blood Alcohol Concentration Levels in Canada

A warm breeze, a few friends, and a cold drink after work on a sunny patio. In the summer months, it’s hard to resist the temptation to relax with a few cocktails after a hard day at the office. But the fact remains that getting behind the wheel with a blood alcohol level anywhere near the legal limit is extremely risky; both from a safety and legal standpoint.

As a Criminal Defence Lawyer in Toronto, I’ve defended a great number of clients facing impaired driving charges, and secured positive outcomes time and time again. But over the years, I’ve found that the easiest way for a person to avoid a DUI charge is to understand and habitually follow the legal limit regulations.

What is the “Legal Limit”?
In Canada, the legal Blood Alcohol Concentrate (BAC) level is .08%. That being said, nearly every province and territory in the country has administrative laws for drivers with BAC’s much lower. While you may not receive criminal impaired driving charges at .04 or .05%, you will receive an immediate license suspension ranging from 24 hours to one week. For repeat infractions, the penalty can escalate to include vehicle impoundments, educational program requirements, and even alcohol ignition interlocks.

How do Police test BAC levels?
When you drink an alcoholic beverage, alcohol travels into your blood stream. As the alcohol flows through your body, it is released into your lungs in the same proportion as its concentration in your blood. When you blow into a roadside breath screening device, the police are able to rate your BAC as either a Pass (under .04% or .05 depending on the region), Warn (.05 to .08%), or Fail (higher than .08%). A Fail reading will earn you an arrest for driving with a BAC over .08 and a trip to the nearest police station for further breath testing with an Intoxilyzer and breath technician.

So how much can I drink before I hit the warn range or blow over .08%?
This is always the next question, but it’s impossible to give a general answer. In defending against numerous impaired driving cases over the years, I’ve consulted extensively with many toxicologists about how much a single drink will contribute to a particular person’s BAC and the rate at which alcohol will be eliminated from their body. Those calculations are different for everyone, and depend on factors like gender, age, body weight, body type, and potentially several others. There is also a lag time between when an alcoholic beverage enters the stomach and when it is fully absorbed into the blood (the alcohol must be absorbed into the blood before it can contribute to the BAC level).

At the end of the day, you’re taking some measure of risk if you are driving after having consumed any amount of alcohol. For some people, as few as two drinks consumed within a short period of time will put them over .05. Furthermore, the standard-size single serving drink of one bottle of beer or one glass of wine or one shot of liquor is often not adhered to in the summer months, when one is drawn to pints of craft beer, pitchers of sangria, and sugary (and boozy) cocktails. The calculations go out the window when you can’t even figure out how much you’ve had to drink.

Legally speaking, be warned of this: it is not a defence to a charge of driving with a BAC over the limit to say that you thought your BAC was lower based on what you had to drink. Even if you were a trained toxicologist and you calculated your own BAC before getting behind the wheel, or you used some kind of breath testing device at the bar before leaving and it said you were under the limit, the only thing that matters is whether you voluntarily consumed alcohol and what your actual BAC was while you were behind the wheel.

Also, never forget that you can be charged with the offence of impaired driving even if your BAC falls below the legal limit. It is illegal to drive while your ability to operate a motor vehicle is impaired by alcohol, even to a slight degree. For some people, in some situations, alcohol will affect them such that their ability to drive is negatively affected even while their BAC is under the legal limit. This means that if you get in an accident because those few drinks you had affected your reaction time or your judgment, you’re not necessarily in the clear just because you end up blowing under .08 when the police test you.

In conclusion, understanding how drinking affects your BAC and your ability to legally drive is important, but the safest advice is to plan not to drive if you plan on doing any drinking. Aside from that, it’s always wise to keep the phone number of a skilled Criminal Defence Lawyer on hand. Should you be investigated by police regarding your BAC or impaired driving, a trusted Criminal Lawyer’s advice can mean the difference between going home and going to jail. As a Criminal Defence Lawyer in Toronto, I’ve defended countless clients in impaired driving cases, facilitating the best possible results under every kind of circumstance. Should you be facing charges related to impaired driving or driving with a BAC over .08, call or email my office today for a free and confidential consultation.