Why is drinking and driving so dangerous

For most of us, turning 18 means getting your licence – which is pretty sweet. Getting behind the wheel after you have a few drinks isn’t though.

When you think about it, driving is really complicated. You need total concentration, good coordination, rapid reflexes and to be able to make correct judgments and decisions. So it isn’t surprising that drinking alcohol diminishes that.

Safe drink driving? There’s no such thing.

Australia has strict laws about drinking alcohol and driving, with the legal limit set at .05 blood alcohol concentration (BAC) for full licence holders. Learners and probationary licence holders must have a .00 BAC. Other licence types may vary.

The effects of alcohol on your driving can include:

  • reduced ability to judge speed and distance
  • false sense of confidence and increased tendency to take risks
  • reduced co-ordination and concentration
  • slower reaction times
  • impaired vision and impaired perception of obstacles.

Excessive drinking may also mean that you still have alcohol in your system the next day.

If you are going to drink, the safest option is to arrange alternative transport or accommodation ahead of time.  Stay at a friend’s place, use public transport or a ride-sharing service, or choose a designated driver to ensure you get home safely.

Although traffic fatalities are lower than they were at the turn of the century, alcohol-related crashes still kill about 10,000 people per year in the United States, with alcohol being a factor in one out of three motor vehicle deaths.

Despite all the warnings, public awareness and educational programs, and stiffer penalties for violations, people will still get behind the wheel of their vehicles while intoxicated. Drunk driving numbers for high schoolers decreased by half between 1991 and 2012, but teens are still at risk whether they are the drivers or not.

Motor vehicle wrecks are the leading cause of death in the United States for persons between 15 and 24, whether as the driver or the passenger. Among drivers ages 16-20 who die in crashes, around one in five had at least some alcohol in their system.

According to a 2014 study, an adult driver with a blood alcohol concentration (BAC) of 0.08 is seven times more likely to be involved in a fatal motor vehicle crash than a sober driver. Young adult drivers (ages 21-34) with a 0.08 BAC are 12 times as likely to be in a fatal car crash than drivers who haven't had alcohol.

Basically, the more you drink, the more likely you are to have a fatal accident. The odds of having any vehicle accident, fatal or otherwise, increase at similar rates. Here are the cold, hard facts.

A 160-pound person drinking two 12-ounce beers within an hour would probably have a BAC of 0.04, well below the legal limits of driving under the influence, but 1.4 times more likely to have an accident than someone who is sober.

One of the problems with setting the legal limit for "drunk driving" at a blood-alcohol content level of 0.08 is it sends the message that if you are not yet legally drunk, you are therefore okay to drive.

The problem lies in the fact that impairment begins long before you reach the 0.08 level. Scientific research explicitly shows that some of the skills that you need to drive safely begin to deteriorate even at the 0.02 blood-alcohol level.

Experiments have shown that drivers at the 0.02 level experience a decline in visual functions—their ability to track a moving object—and experience a decline in the ability to perform two tasks at the same time.

If you had those first two beers that raised your BAC to 0.04 and now you drink two more beers to raise your BAC to 0.08, your likelihood of an accident goes up drastically. At 0.08 BAC, a driver is 11 times more likely than the non-drinking driver to be involved in a crash. As the amount of alcohol in the driver's system rises numerically on the BAC scale, the likelihood of a traffic accident multiplies.

Now add two more beers to your total, you are up to having consumed a six-pack and have likely passed the 0.10 BAC level. Your likelihood of having an accident is now 48 times higher than the abstainer.

Two more beers: Hey, you've already had a six-pack, two more couldn't hurt, right? Except two more beers could put your BAC close to 0.15, at which point you are 380 times more likely to have an accident.

Play it smart during weekends and holidays. If you plan to party away from home—and this includes on the water—be sure to appoint a designated driver for the car or operator of the boat.

Whatever you do, don't get behind the wheel if you've been drinking.

Consider calling a cab or using a rideshare app to get yourself and your loved ones home safe and protect everyone else on the road. Better yet, if you are going to be drinking away from home, use those options to get to the party so you don't have a car handy that you'll be tempted to drive when your judgment is impaired by alcohol.

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  1. National Highway Traffic Safety Administration. Trends: Alcohol: Table 13: People Killed, by Highest Driver Blood Alcohol Concentration (BAC) in the Crash, 1982-2019.

  2. Centers for Disease Control and Prevention. Teen Drinking and Driving.

  3. National Highway Traffic Safety Administration. Trends: Alcohol: Table 18: Drivers in Fatal Crashes, by Blood Alcohol Concentration (BAC) and Age Group, 1982-2019.

  4. Romano E, Torres-Saavedra P, Voas RB, Lacey JH. Drugs and Alcohol: Their Relative Crash Risk. J Stud Alcohol Drugs. 2014;75(1):56-64. doi:10.15288/jsad.2014.75.56

  5. Voas RB, Torres-Saavedra P, Romano E, Lacey JH. Alcohol-Related Risk of Driver Fatalities: An Update Using 2007 Data. J Stud Alcohol Drugs. 2012;73(3):341-350. doi:10.15288/jsad.2012.73.341

  6. Centers for Disease Control and Prevention. Impaired Driving: Get the Facts.

  7. National Institute on Alcohol Abuse and Alcoholism. Alcohol Alert No. 31 PH 362 January 1996.

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