CDL Driving Safely: Alcohol and Drugs

Alcohol and the Brain

  • Goes through the bloodstream to the brain.
  • Liver has limited ability to filter alcohol out of your blood.
  • If you drink faster than your body can process the alcohol, you feel the effects of the alcohol.

Blood Alcohol Concentration (BAC)

  • Blood Alcohol Concentration: the amount of alcohol in your body.
  • All of the following drinks contain the same amount of alcohol:
    • 12 ounce glass of 5% beer
    • 5 ounce glass of 12% wine
    • 1 ½ ounce shot of 80 proof liquor
  • BAC is determined by the amount of alcohol you drink, how fast you drink and your weight.

Alcohol and Driving

  • The only safe driving limit of Blood Alcohol Concentration is .00
  • Affects more and more of the brain as the BAC builds up.
  • First part of the brain affected controls judgement and self control.
  • Muscle control, vision and coordination are also impacted.
  • By a BAC of 0.15, you are physically unable to drive.
  • Driving and drinking can cause:
    • Increased reaction time to hazards.
    • Driving too fast or too slow.
    • Driving in the wrong lane.
    • Running over the curb.
    • Weaving.

Other Drugs

  • Legal and illegal drugs can impact driving.
  • Possession and use of a drug is only permitted if a doctor informs the driver  that it will not impact his driving ability.
  • Don’t use drugs that hide fatigue.


  • If you become too ill to drive, you should stop as soon as possible.