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Alcohol & Driving

Alcohol consumption is known to impair a driver’s ability to safely operate a motor vehicle. Drinking alcohol before getting behind the wheel significantly increases the likelihood of a traffic crash. 

  • The ratio of alcohol to blood in the body is called the Blood Alcohol Concentration, or BAC.  The higher a driver’s BAC, the more impaired she will be. 
  • Two people can drink the same amount of an alcoholic beverage, but their BACs can be different. Gender, body weight, strength of the drink, size of the drink, whether there is food in the stomach, and time spent drinking are all factors that impact a person’s BAC and therefore their level of impairment.

Driving under the influence of alcohol is illegal. 

  • All states have per se laws which make it illegal to drive with a BAC of .08 of higher.
  • Impairment can occur at BAC levels as low as .02, which is why a driver can be arrested with a BAC lower than .08 if a law enforcement officer has probable cause to believe the driver is impaired.

Here are some of the ways in which drinking alcohol over the course of one hour can affect a 150-pound adult. The beverage used in these examples is a 12 ounce beer.

  • After One Drink, Inhibitions Are Lowered
    A person may be less critical of him or herself and others, and judgment begins to be affected. Coordination may also be affected. (BAC: 0.02-0.03 percent).
  • After Two Drinks, Reaction Time Will Be Slower
    A person may appear relaxed and friendly. Reaction time begins to slow. (BAC: 0.04-0.05 percent).
  • After Three Drinks, Judgment Is Not Sound
    A person will not think clearly and may do or say things that are rude or unreasonable, and reasoning is less reliable. Reaction time slows down. (BAC: 0.06-0.07 percent).
  • After Four Drinks, Hearing, Speech, Vision and Balance Are Adversely Affected
    A person may have difficulty enunciating words. As eye muscles become more relaxed, focusing and tracking becomes more difficult. Although the drinker may not be aware of it, reaction time is greatly slowed. (BAC: 0.08-0.09 percent).
  • After Five Drinks, Most Behaviors Are Affected
    Body parts do not seem to work together. Speech may be slurred. Performing any task that requires the use of hands and feet is difficult. Walking without stumbling also is difficult. (BAC: 0.10-0.11 percent).
  • After 12 Drinks, A 150-Pound Person’s BAC Would Be About 0.30 Percent
    At this level, a coma or deep sleep is not unusual. If there is enough alcohol in the stomach when the person passes out, the blood-alcohol level will continue to rise. If the BAC reaches 0.40 percent, the person may fall into a deep coma and die.