Driving under the influence of drugs or alcohol is a severe offense, but it is also common. In 2015, for example, there were almost 8,000 impaired driving charges laid in British Columbia alone. For many people who drive under the influence of drugs or alcohol, however, an impairment may not be their first thought when they get behind the wheel. What is impaired driving? How can you tell if someone else is impaired by drugs or alcohol while driving? What are some of the risks associated with impaired driving? And finally: how can you avoid an accident with an impaired driver?

What is impaired driving?
The term "impaired driving" refers to operating a motor vehicle while impaired or not able to use the car safely. The most common causes of impairment are alcohol and drugs. A person acts with "criminal negligence when he or she drives a motor vehicle on a highway while being impaired by drugs or alcohol" (Criminal Code, RSC 1985, c C-46).
Other substances can also cause impairment, including prescription medication and illegal drugs.
What is the legal definition of impairment?
You are legally impaired if your blood alcohol concentration (BAC) is 0.08% or higher. That means that if you have a BAC of 0.08%, it's possible that you will suffer from some level of impairment.
The amount of alcohol in your system depends on several factors, including:
Your body weight
How much food you've recently eaten
How quickly you've been drinking
Who is most at risk of impaired driving?
Young men are the most likely to be involved in fatalities from impaired driving. In 2015, 65% of drivers killed in crashes involving an alcohol-impaired driver were male.
Drivers who have had a few drinks are also at risk of being involved in fatal motor vehicle crashes caused by alcohol impairment. Nearly 30% of all people involved in fatal crashes had blood alcohol concentration (BAC) levels between 0.01 and 0.07%.
What are the risks of impaired driving?
The consequences of impaired driving are severe: accidents involving injury; loss of life; economic losses due to health care costs and property damage; lost productivity at work or school; decreased quality of life for victims who survive; harm caused by second-hand smoke at bars and restaurants where minors may be present; the increased likelihood that the offender will repeat this behaviour if they continue to drive after drinking alcohol or using drugs (known as "repeat offending"); negative impact on public perception about law enforcement agencies ability to enforce laws against impaired drivers (e.g., when penalties appear too lenient); increased stress levels for police officers having conversations with suspected drunk drivers during traffic stops (because some people become aggressive); etcetera ad nausea...