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Alcohol or Drug Impaired Driving

According to Société d'assurance automobile du Québec (SAAQ) data, drunk driving is one of the main causes of accidents in Québec.

To reduce the number of motorists driving under the influence of alcohol, the SPVM sets up roadside checks at various times of the year.

When a Police Officer suspects a driver of having consumed alcohol, the driver will be subjected to a breathalyzer test to detect alcohol.  Drivers who fail the test are arrested; those who pass it are released.

Drugs and driving

It is not only alcohol that can affect your ability to drive. Other substances, like cannabis, affect it as well.

A lot of drivers underestimate the consequences of driving under the effects of cannabis, but the impact is significant, as you can see for yourself in the list below:

  • Trouble concentrating and paying attention to the road environment
  • Poor coordination
  • Slower reaction time, slower reflexes and hesitant driving
  • Risk of not being prepared for the unexpected

Alcohol level

Did you know that drivers can be charged with driving under the influence even if their alcohol level is lower than the legal limit?

In Canada, there are two criminal violations in regards to alcohol at the wheel:

  • The more widely known, applies when a person driving a motor vehicle with a blood alcohol content higher than 80 mg alcohol per 100 ml of blood, i.e. the violation of Section 253 b) of the Criminal Code.
  • Under the terms of Section 253 a), it is also possible to be stopped and charged when driving is impaired by alcohol, and in this case, the blood alcohol level does not matter, even when lower than .08!

Therefore, the number of alcoholic drinks consumed should never be your only criteria to determine if a person is able to drive. You must evaluate if drinking has decreased the person’s ability to drive, which can occur as early as the first drink, especially if it is accompanied by other factors like fatigue, stress, drugs, health issues (e.g.,: a cold), etc

Effects of alcohol

Alcohol mainly affects the central nervous system by impairing intellectual, sensory and motor functions.

Intellectual functions

These are the first to be affected by alcohol, decreasing one's attention, self-control and ability to judge. 

Sensory functions

Hearing and especially sight are affected by alcohol, leading to:

  • Greater difficulty adapting to night vision and slower recovery from glare
  • Change in  depth perception
  • Reduced peripheral vision (tunnel effect)
  • Double vision when blood alcohol content reaches 100 mg alcohol per 100 millilitres of blood (mg%), an occurrence that is further amplified after surpassing 150 mg %

Hearing is also impaired when one is inebriated.

Motor functions

Alcohol impairs muscle control and coordination, causing the following behaviours:

  • Staggering
  • Difficulty in clearly pronouncing words
  • Loss of manual dexterity
  • Loss of precision in gestures and movements

Driving a car is a complex activity that requires the execution of several simultaneous tasks. The driver must be able to perceive, interpret and react to events, which proves difficult when faculties are impaired by alcohol!

Symptoms of alcohol impairment

Several symptoms appear when a person's abilities are weakened by alcohol. In fact, Police Officers watch for them when deciding whether to make an arrest. If you notice these symptoms in friends, try to convince them not to drive, and more importantly, do not get in the vehicle with them. If they still insist on driving, call 911!

  • Irritated eyes
  • Difficulty talking
  • Difficulty standing straight
  • Difficulty walking in a straight line
  • Slow gestures
  • Distracted behaviour
  • Slow response to questions
  • Tendency to fall asleep
  • Increased feelings of sadness
  • Aggressiveness
  • Uncontrolled and exaggerated giggling
  • Faster breathing
  • More profuse perspiration
  • Accelerated speech
  • Talking loudly

Sources: SAAQ and the École nationale de police du Québec

Zero tolerance alcohol for drivers aged 21 or younger

Since April 2012, driving after drinking alcohol is prohibited for driver's licence holders aged 21 or younger, and for those with a learner's licence or probationary licence.

To know more : 
Zero Alcohol for Drivers Age 21 or Younger - SAAQ

Find out more


Despite all the information about drinking and driving that has been communicated for many years, there are still many myths. Here are some questions that are most frequently asked:

Since I had a good meal after drinking, am I able to drive my vehicle?

NO. When we drink without eating anything before, the stomach is empty so the alcohol goes directly into the small intestine and then into the bloodstream and to the brain. The assimilation is done without any barrier so the alcohol goes right to your head. That explains the rapid effect of alcohol in this kind of situation. And eating something after drinking does not change anything, the alcohol is already present in the circulatory system so it is too late.

I drank with food, so can I drive my vehicle?

NO. It is true however that the process of assimilating alcohol is different when you drink with food, because the food in your stomach absorbs a certain amount of alcohol. As well, even though the food is not completely digested, the sphincter between the stomach and the small intestine contracts to delay the passage of food and alcohol in the intestine.  The assimilation process is therefore longer, which means that the alcohol goes into the bloodstream more slowly. However, even the most lavish meal does not prevent a person from becoming intoxicated.

After I drank, I danced and sweated and I even had a cold shower, so can I drive my vehicle?

NO. Taking a cold shower, walking or even going crazy on the dance floor has practically no effect on alcohol, since it is 90% eliminated by the liver. Less than 10% of alcohol can be eliminated by other means, such as in urine, breathing and perspiring. To sober up, you have to wait for the liver to complete its process of converting the alcohol.

It's been over an hour since I had a drink, can I drive my vehicle?

NO. It is right not to consume alcohol an hour before driving a vehicle. But this good habit is only beneficial if alcohol consumption is kept to a minimum. In fact, waiting one hour will not at all change the state of a person who has drank too much, since the body eliminates alcohol at a much slower rate than it assimilates it. Since the liver eliminates on average 15 mg of alcohol per hour, to eliminate 80 mg as an example, would generally take more than 5 hours.

I only drank beer so can I drive my vehicle?

NO. Some people even think that beer affects behaviour less than other types of alcoholic drinks. According to the standard sizes for each type of drink, a beer is equivalent to a glass of wine, an aperitif, or hard liquor since they contain the same amount of alcohol. So drinking three beers or three scotchs means that the same amount of alcohol is consumed.

After drinking, I had a good strong cup of coffee so can I drive my vehicle?

NO. Black coffee does not sober up anyone, even if this gives the impression of clearing your head. Why? Because even though caffeine stimulates the nervous system, it has no effect on alcohol levels. It is therefore critical not to trust the effect felt after having coffee since the effects of alcohol are still very present, as is the reduced ability to drive.  To eliminate the alcohol, the liver will take the time required, regardless of coffee.