You have probably noticed that there are various tools to help measure blood alcohol concentration:

• wall-mounted breathalyzers (located in certain commercial establishments)
• portable breathalyzers
• smartphone accessories
• apps or websites where users manually enter their usage parameters
• single-use tubes

Many factors influence the results of a blood alcohol concentration test, including the device’s reliability, maintenance, calibration, misuse when used while drinking alcohol, the fact that the absorption and elimination of alcohol varies from one individual to the next, and the fact that blood alcohol concentration can keep increasing up to one hour after the last drink.

Remember that:

• many types of drivers are subject to the zero alcohol rule or the limit of 50 mg of alcohol per 100 ml of blood
• the Criminal Code not only penalizes driving with a blood alcohol concentration equal to or above 80 mg per 100 ml of blood, but also considers that driving while one’s ability to do so is impaired by alcohol or drugs is an offence, regardless of blood alcohol concentration
• many factors that do not affect blood alcohol concentration directly may nonetheless increase its effect on driving (fatigue, medication, drugs, personal tolerance to alcohol, etc.)

With regards to impaired driving, scientific literature amply shows that the increased risk of having an accident is significantly high, well before blood alcohol concentration reaches 80 mg of alcohol per 100 ml of blood.

In other words, it is best to avoid using these tools and devices to prevent impaired driving. Instead, plan on using alternative solutions such as taking a taxi or using a rideshare service, taking public transit, using a drive-home service, having a designated driver or sleeping over.

For more information: What the Law Says, Myths and Facts About Drinking and Driving, Responsibilities and Smart Solutions (SAAQ) and Évaluation de 10 modèles d’alcootest (Protégez-vous, in French only)