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You know that driving is a complicated process that involves many skills. In this activity, you will look at why drinking and drugs do not mix with driving.

Below are some of the skills you have to focus on when driving.

Seeing: You must be able to watch the road in front of and around the vehicle, to use your mirrors, to check behind you, to check your speedometer, etc.
Hearing: You must be aware of oncoming vehicles, especially emergency vehicles. You also have to listen for traffic around you and listen to your vehicle.
Coordination: You must be able to control the steering wheel so the vehicle goes where you want it to go. You also must be able to work the pedals, signals, lights, etc.
Thinking: To anticipate what is going to happen next on the road, you must be aware of the other vehicles around you. Pay attention to the weather and road conditions and be alert to avoid any potential hazards that might come your way.

You may know that drinking alcohol or using both prescription and nonprescription drugs will affect your skills and abilities in all of these areas. Your judgment, reaction time, and perception are all affected by the use of alcohol and/or drugs so that you are not able to respond appropriately or quickly enough to hazardous situations on the road.

This kind of notice may be on over-the-counter drugs you take or drugs prescribed by your doctor.

Alcohol

Alcohol is absorbed from the stomach and the small intestine directly into the bloodstream. Your body sees alcohol as a poison. The liver produces enzymes that change alcohol into safer chemicals. But once you have consumed just one drink, that is too much alcohol for the liver to deal with all at once. The alcohol will move through the blood and have toxic effects.

Alcohol is a depressant. That means it slows your reaction time. Alcohol also lowers your coordination and makes you sleepy when it reaches your brain tissue.

Blood Alcohol Concentration

In 2014, 15.9% of all drivers involved in fatal collisions in Alberta had consumed alcohol before the crash. How would you know whether or not you have had too much alcohol and should not drive? The court system uses a BAC (blood alcohol concentration) reading. BAC is the number of milligrams of alcohol in a millilitre of blood. If your BAC is 0.08, this means that there are 0.08 mg of alcohol in each mL of your blood. Each individual’s BAC depends on the number of drinks they have consumed and their body weight. (One drink is defined as 45 mL of hard liquor (40%), 150 mL of wine (11%), or 350 mL of beer (4%).)

How much a person can drink depends on their body weight. Two drinks, taken one after the other, will put a person weighing 45 kg (100 lb.) or less over the legal limit. Someone who weighs 110 kg (240 lb.) may be able to have between four or five drinks, one after the other, before they reach the legal limit. BAC does not take into account the amount of food or sleep that a person has had or the rate at which a person drinks. Generally speaking, having one drink an hour is considered safe for driving. But a person who is hungry or tired may become impaired more quickly.

As well, BAC does not take years of drinking experience into account.n older, heavy drinker might have a BAC of 0.8 (10 times higher than the legal limit) but not show any signs of impairment. Someone younger or smaller can have a BAC well below the legal limit and be too impaired to drive safely.

A BAC level is not the only measure of impairment. People who feel wobbly or dizzy or at all unsure of their abilities should not drive.

What Does the Law Say?

In Canada, having a BAC level of 0.08 is generally considered the legal limit. But the police can charge drivers who have any alcohol on their breath when they are pulled over. Drivers are considered to be impaired when their reactions are slower than normal. This would include slow or slurred speech and the inability to walk in a straight line. The charge would be impaired driving.

Digging Deeper

Click here to go to the Know Your Limits website to find out about penalties for driving after drinking.

You can also estimate your blood alcohol content by clicking on the link below.

Self-Check

Try This!

Try the questions below on your own first and then click on the tab to check your answers!

1. Name two things that are affected by the use of alcohol and/or drugs so that you are unable to respond appropriately or quickly enough to hazardous situations on the road.

2. What does it mean when it is said that alcohol is a depressant?

3. What does the court system use to determine whether or not a person has too much alcohol in their system and should not drive?

4. In Canada, what is the legal limit for drinking and driving?

5. Even without a BAC reading, the police can charge drivers who have any alcohol on their breath. What would be signs of being impaired?

Check your answers here!

1. You might have said: Your judgment, reaction time, or perception are affected by the use of alcohol and/or drugs.

2. It means that alcohol slows your reaction time. Alcohol also lowers your coordination and makes you sleepy when it reaches your brain tissue.

3. The court system uses a BAC (blood alcohol concentration) reading.

4. In Canada, having a BAC level of 0.08 is generally considered the legal limit.

5. Signs of being impaired include slow or slurred speech and the inability to walk in a straight line.

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