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Driving and Alcohol

Beer And KeysAlcohol and automobiles are a deadly mix. Each year in the United States, thousands lose their lives because an impaired driver made a reckless decision to drink and drive, and hundreds of thousands more are injured. Several measures have been adopted to prevent such tragedies, but the numbers still remain high. Preventive measures include:

  • increasing the age of alcohol purchase and consumption to 21 nationwide
  • lowering the legal blood alcohol concentration level
  • roadside sobriety checks
  • awareness programs such as designated driver initiative
  • revoking driver's license of violators
  • vehicle safety equipment such as airbags, seatbelts, etc.
  • mandatory education programs for drunk drivers about alcohol and its hazards
  • public service prevention messages (television, billboards, radio)
  • school-based programs to educate about alcohol and teach refusal skills

Alcohol is a depressant. It is absorbed into the blood stream and affects body functions. Although quickly absorbed, it remains in the body for an extended period of time. Many mistakenly believe that strong coffee or a cold shower will alleviate the effects of alcohol. These remedies do not work, however; only time will eliminate alcohol from the body.

Alcohol has a profound effect on driving skills. Because of its depressant effects, drivers can misjudge their capabilities. Some of the effects of alcohol that affect driving include:

  • reaction time - slow reflexes can decrease the ability to react swiftly to situations
  • vision - eye muscles function more slowly. Eye movement and perception are altered, possibly resulting in blurred vision. Night vision and color perception are also impaired.
  • tracking - the ability to judge the car's position on the road, the location of other vehicles, center line, road signs, etc., can be adversely affected.
  • concentration - attention to driving may decrease and/or drowsiness may occur
  • comprehension - the depressant effect of alcohol hinders the ability to make rational decisions
  • coordination - the mechanics of driving can be affected by reduced eye/hand/foot coordination.

If alcohol is used in conjunction with other drugs (legal or illegal), the effects of both substances can be increased -- a potentially deadly situation. Education efforts should include increased awareness about this synergistic effect as well. In the case of prescription drugs, health professionals must educate patients about the dangers of combining alcohol with medications.

The effects of alcohol are determined by body weight and time.

Blood Alcohol Concentration Levels

(within one hour of consumption)

Number of Drinks Consumed

Body Weight (lbs)

(impaired in some states)


.10 and above
(intoxicated in all states)


As you can see in the chart above, blood alcohol concentration is affected by weight and number of drinks ingested. If you are going to drink, the safest course of action is to make alternative transportation arrangements. These might include:

  • public transportation
  • taxis
  • designated drivers
  • prior arrangements to stay overnight
  • calling someone to pick you up

If you observe a drunk driver, do not attempt to approach with your vehicle. Instead, call the police. Drunk drivers are risking their own lives and the lives of others. Signs of a drunk driver include:

  • unable to stay within the lane
  • driving too fast
  • driving too slow
  • taking wide turns
  • slowing down and speeding up erratically
  • driving too close behind another vehicle
  • pulling over recklessly
  • driving without using headlights

Students Against Drugs and Alcohol

Alcohol Impairment Chart

BAC and Blackouts

Blood Alcohol Concentration Calculator

Drink Wheel

Knowing Your Limit: