Are you over the limit?

Sometimes people rely on rules such as the number of drinks consumed in an hour to estimate if they are OK to drive. Relying on these calculations is risky – especially when the stakes are as high as they are in drunk or drugged driving. These calculations assume that the person has consumed a standard drink but in reality there is no such thing. The alcohol content of what is being served will depend on what you’re drinking, the size of the glass and even based on the brand you are drinking. Even if you could accurately calculate how many grams of alcohol you have consumed, factors such as your body type, weight, food consumption and the time of day you are drinking will all affect your actual blood alcohol level.

These rules and calculations also give you no information about whether your ability to drive is impaired. Regardless of your blood alcohol level it is a crime to drive when your ability is impaired by alcohol or drugs. Because consuming these substances affects your ability to make judgments, your own estimation of your condition is not reliable.

A 2014 study revealed the effects of combining alcohol and marijuana. When a driver combines the two, the risk of performing an unsafe driving action increases by 8-10% for every additional .01 rise in BAC—and that is over and above the increased risk created by the alcohol alone.

The Toronto Star Archives, courtesy of Toronto Public Library

Fig. 3.
A driver administers a do-it-yourself breathalyzer test, 1969.

Do-it-yourself breathalyzers are still widely available, but are not nearly as accurate as the breathalyzers used by law enforcement agencies.

Activity: Why do people drive while under the influence?

The legal consequences for driving while under the influence are steep. However, there is a simple way to stay one step ahead of the law... just don’t drive unless you’re sober.

If you do find yourself or a friend under the influence, there are countless alternatives to driving. These include:

calling a cab
asking a friend or parent for a ride
giving a ride to a friend who is impaired
taking a bus
walking
staying the night

There are good reasons why driving under the influence is against the law: There are so many negative possible outcomes for you and for society if you do it. And there are so many other options. So why do people do it?

Brainstorm a list of all the ways that people can avoid driving under the influence.
1. For each item on your list, think about times it has been successful in stopping people from doing so.
2. The fact of the matter is people continue to drive under the influence. Look back to your list. For each item, consider why people would not pursue that option.
What would you do to further reduce impaired driving?