The Dangers of Impaired Driving

Driving Skills Can Deteriorate Quickly If You Are Drinking

Drink and Car Key
Impairment Starts Long Before .08 Level. © Getty Images

If you have only had a couple of drinks and are far from being legally intoxicated, it still probably is a good idea not to be driving a vehicle. Your driving can become impaired long before you reach the intoxication level.

All 50 states have passed laws that set the legal limit for driving while intoxicated with a blood alcohol concentration of .08. The problem is your ability to react and perform, -- and therefore drive safely -- can become affected long before you reach the level of legal intoxication.

Most people think they can drive after having a couple of drinks, but tests show that even small amounts of alcohol can affect you physically and your driving skills.

At the .02 BAC Level

According to the National Highway Traffic Safety Administration (NHTSA), these are the typical effects felt at the .02 BAC level, or after one drink for women and two drinks for men:

  • Some loss of judgment
  • Relaxation
  • Slight body warmth
  • Altered mood
  • Decline in visual functions (rapid tracking of a moving target)
  • Decline in ability to perform two tasks at the same time (divided attention)

At the .05 BAC Level

NHTSA testing also shows that at the .05 level, or approximately 3 drinks for women or 5 for men, the following effects can be detected:

  • Exaggerated behavior
  • May have loss of small-muscle control (focusing your eyes)
  • Impaired judgment
  • Usually good feeling
  • Lowered alertness
  • Release of inhibition
  • Reduced coordination
  • Reduced ability to track moving objects
  • Difficulty steering
  • Reduced response to emergency driving situations

At the .08 BAC Level

If you reach the .08 BAC level, barely on the borderline of being legally intoxicated for the purposes of driving, your reactions and driving skills can be seriously impaired:

  • Muscle coordination becomes poor (balance, speech, vision, reaction time)
  • Hearing is impaired
  • Harder to detect danger
  • Judgment, self-control, reasoning, and memory are impaired
  • Concentration impaired
  • Short-term memory loss
  • Speed control
  • Reduced information processing capability (signal detection, visual search)
  • Impaired perception

As you can see, long before you feel drunk or even act drunk, the skills and abilities that you need to drive a vehicle safely can be impaired. You may seem "fine" and may not appear to others to be intoxicated, but you may not be able to make that split-second reaction that could prevent a traffic collision.

This is the reason that you should never drink and drive no matter how much or how little you have had to drink. If your reaction time or motor skills are impaired even a little it could mean the difference between life and death if you are behind the wheel.


National Highway Traffic Safety Administration. "The ABCs of BAC - A Guide to Understanding Blood Alcohol Concentration and Alcohol Impairment." February 2005.

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