When people think about impaired driving, they usually think about the legal limit—0.08% blood alcohol concentration (BAC). But most provinces now issue penalties for drivers caught in the “warn range”, starting at 0.05%. That means you can lose your licence, get fined, and have your car impounded without being legally drunk. And with new U.S. legislation requiring cars to be equipped with impaired-driver detection technology expected as early as 2026, Canada may not be far behind. All of which raises the question: how does BAC actually work?
BAC is a measure of how much alcohol is in your bloodstream. One standard drink in Canada—roughly a bottle of beer, a glass of wine, or a shot of spirits—can take about two hours for your body to metabolize. On average, two drinks in an hour might put a man close to 0.05%; for a smaller woman, it could take less. But those estimates don’t apply evenly. Body size, sex, food intake, and how quickly you consume alcohol all influence how fast your BAC rises.
Despite the myths, nothing sobers you up but time. Coffee, showers, or fresh air won’t lower your BAC—and even a night of “moderate” drinking can leave you over the limit well into the next morning. Still, many people take the risk. A national survey by the Traffic Injury Research Foundation found that over one-third of Canadian drivers admitted to driving when they weren’t sure whether they were over the legal limit. If there’s any doubt, don’t get behind the wheel. The safest choice is always to plan ahead and leave the car out of the equation.
