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. Why can common over-the-counter cold medicines be a concern for drivers?

   Correct answer: They can make you drowsy or affect safe driving

   Certain prescription and over-the-counter drugs, such as cold medicines, can make a driver drowsy or otherwise reduce safe-driving ability.

   Source: Missouri CDL Manual — Section 2.22: Alcohol, Other Drugs, and Driving

2. 2. Should you ever use a drug to hide the feeling of fatigue while driving?

   Correct answer: No, because the only cure for fatigue is rest

   You should not use any drug that masks fatigue; the only real cure for being tired is rest.

   Source: Missouri CDL Manual — Section 2.22: Alcohol, Other Drugs, and Driving

3. 3. Which driving abilities does alcohol impair?

   Correct answer: Coordination, reaction time, depth perception, and judgment

   Alcohol dulls your coordination, slows reaction time, and weakens both depth perception and night vision, and it affects the brain's judgment and inhibition.

   Source: Missouri CDL Manual — Section 2.22: Alcohol, Other Drugs, and Driving

4. 4. Which of these contains about the same amount of alcohol as the others?

   Correct answer: A 12-ounce beer, a 5-ounce glass of wine, and a 1.5-ounce shot are about equal

   A 1.5-ounce shot of 80-proof liquor holds about as much alcohol as a 5-ounce pour of 12% wine or a 12-ounce serving of 5% beer.

   Source: Missouri CDL Manual — Section 2.22: Alcohol, Other Drugs, and Driving

5. 5. As blood alcohol concentration rises, which mental function is affected first?

   Correct answer: Judgment and self-control

   The earliest part of the brain impaired controls judgment and self-control—which can even prevent a drinker from realizing they are getting drunk.

   Source: Missouri CDL Manual — Section 2.22: Alcohol, Other Drugs, and Driving

6. 6. What is the only thing that will actually reduce your blood alcohol level?

   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 black coffee or a cold shower.

   Source: Missouri CDL Manual — Section 2.22: Alcohol, Other Drugs, and Driving

7. 7. According to the manual, how much alcohol does it take to begin showing signs of impairment?

   Correct answer: For some people, just one drink

   For some people, a single drink is enough to start showing signs of impairment.

   Source: Missouri CDL Manual — Section 2.22: Alcohol, Other Drugs, and Driving

8. 8. Which factors determine a person's blood alcohol concentration?

   Correct answer: The amount and speed of drinking, and body weight

   BAC depends on how much alcohol you drink, how fast you drink it, and your body weight, since a smaller person reaches a given level with less alcohol.

   Source: Missouri CDL Manual — Section 2.22: Alcohol, Other Drugs, and Driving

9. 9. How does alcohol interact with other drugs a driver might take?

   Correct answer: It can make their effects much worse

   Alcohol can intensify how other drugs affect you, so the safest rule is to never combine drugs with driving.

   Source: Missouri CDL Manual — Section 2.22: Alcohol, Other Drugs, and Driving

10. 10. What do the regulations say about being under the influence of a controlled substance while on duty?

    Correct answer: It is prohibited

    The rules bar a driver on duty from being impaired by any controlled substance, amphetamine, narcotic, or other product that could make driving unsafe.

    Source: Missouri CDL Manual — Section 2.22: Alcohol, Other Drugs, and Driving

11. 11. Under what condition may a driver use a drug prescribed by a doctor?

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

    A driver may use a doctor-prescribed drug if the doctor confirms it will not interfere with the ability to drive safely.

    Source: Missouri CDL Manual — Section 2.22: Alcohol, Other Drugs, and Driving

12. 12. About how much alcohol can the liver process in an hour?

    Correct answer: Roughly one-third of an ounce

    The liver removes only about a third of an ounce of alcohol each hour, which is less than what a single standard drink holds.

    Source: Missouri CDL Manual — Section 2.22: Alcohol, Other Drugs, and Driving