Alcohol & Drugs

Study questions with answers

12 sample Alcohol & Drugs questions with the correct answer, a short explanation, and the official handbook reference. Read through them, then take the quiz above.

1. 1. When may a driver use a prescription drug a doctor has provided while driving a CMV?

   Correct answer: If the doctor says it will not affect safe driving

   Use of a drug prescribed by a doctor is allowed if the doctor tells the driver it will not affect safe driving ability.

   Source: South Carolina CDL Manual — Section 2: Driving Safely (Other Drugs)

2. 2. At what blood alcohol concentration is it illegal to operate a commercial motor vehicle?

   Correct answer: .04 percent or more

   It is illegal to operate a CMV with a blood alcohol concentration of .04 percent or more.

   Source: South Carolina CDL Manual — Section 1: Introduction (Alcohol, Leaving the Scene, and Commission of a Felony)

3. 3. Why does the manual caution drivers about ordinary cold medicines?

   Correct answer: They can make a driver drowsy

   Over-the-counter cold remedies and similar medicines can make a driver drowsy or otherwise reduce safe-driving ability.

   Source: South Carolina CDL Manual — Section 2: Driving Safely (Other Drugs)

4. 4. As blood alcohol concentration first begins to rise, which mental abilities are affected first?

   Correct answer: Judgment and self-control

   The first part of the brain affected is the part controlling judgment and self-control, which are essential for safe driving.

   Source: South Carolina CDL Manual — Section 2: Driving Safely (Alcohol and the Brain)

5. 5. What is the only thing that will actually reduce the alcohol in your body over time?

   Correct answer: The passage of time

   Because the liver clears alcohol at a fixed rate, only the passage of time will sober you up, not coffee or a cold shower.

   Source: South Carolina CDL Manual — Section 2: Driving Safely (How Alcohol Works)

6. 6. Which of these servings contains about the same amount of alcohol as a 1.5-ounce shot of 80-proof liquor?

   Correct answer: A 12-ounce glass of beer

   A 12-ounce glass of beer, a 5-ounce glass of wine, and a 1.5-ounce shot of 80-proof liquor all hold roughly the same amount of alcohol.

   Source: South Carolina CDL Manual — Section 2: Driving Safely (What Is a Drink?)

7. 7. About how much alcohol can the liver process in one hour?

   Correct answer: About one-third of an ounce

   In one hour the liver can handle only about a third of an ounce of alcohol, well below what a single standard drink holds.

   Source: South Carolina CDL Manual — Section 2: Driving Safely (How Alcohol Works)

8. 8. How does alcohol interact with the effects of other drugs?

   Correct answer: It can make their effects much worse

   Drinking can greatly amplify how other drugs affect you, which is one more reason to keep them out of driving.

   Source: South Carolina CDL Manual — Section 2: Driving Safely (Other Drugs)

9. 9. What is the safest rule about combining drugs and driving?

   Correct answer: Do not mix drugs with driving at all

   The safest rule is not to mix any drugs with driving at all, since drug use can lead to crashes, injury, and death.

   Source: South Carolina CDL Manual — Section 2: Driving Safely (Other Drugs)

10. 10. What happens if a CMV driver is found to have any detectable amount of alcohol below .04 percent?

    Correct answer: The driver is put out of service for 24 hours

    A driver with any detectable alcohol under .04 percent will be placed out of service for 24 hours.

    Source: South Carolina CDL Manual — Section 1: Introduction (Alcohol, Leaving the Scene, and Commission of a Felony)

11. 11. The manual warns against using drugs to hide fatigue. What is the only genuine remedy for being tired?

    Correct answer: Rest and sleep

    No drug can substitute for rest; the only cure for fatigue is sleep, so never use a substance to mask being tired.

    Source: South Carolina CDL Manual — Section 2: Driving Safely (Other Drugs)

12. 12. If you become too ill to drive safely, what does the manual say you may still do in an emergency?

    Correct answer: Drive to the nearest safe place to stop

    When sickness prevents you from driving safely you must stay off the road, though in a true emergency you may proceed only to the closest safe stopping point.

    Source: South Carolina CDL Manual — Section 2: Driving Safely (Illness)