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Montana CDL — General Knowledge practice

Montana CDL — General Knowledge: Alcohol & Drugs practice test

Blood alcohol limits, zero-tolerance and implied-consent laws, and how alcohol and drugs — legal or not — affect your driving.

Content reviewed against official driver handbooks · August 12, 2026

14 questions · pass with 11 correct. You get instant feedback and an explanation after every answer.

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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.

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  1. 1. After alcohol has passed through the brain, where does the manual say it goes?

    Correct answer: A small share leaves in urine, sweat and breath, and the rest is carried to the liver

    The manual explains that only a small percentage of alcohol is removed through urine, perspiration and breathing. The remainder goes to the liver to be processed.

    Source: Montana Commercial Driver License Manual — Section 2.22.1, Alcohol and Driving

  2. 2. Montana's list of major offenses sets two alcohol concentration thresholds. Which pairing is correct?

    Correct answer: 0.08% or more in a noncommercial vehicle; 0.04% or more in a CMV

    The Montana list treats it as a major offense to drive, or have actual physical control of, a noncommercial vehicle at 0.08% or above, or a CMV at 0.04% or above.

    Source: Montana Commercial Driver License Manual — Keeping Your Commercial Driver License

  3. 3. According to the manual, how does the rate at which the liver handles alcohol compare with the alcohol in a standard drink?

    Correct answer: About one-third of an ounce per hour, well below what a standard drink contains

    The manual says the liver processes only a third of an ounce of alcohol an hour, considerably less than a standard drink holds, and that the rate is fixed. Only time sobers a person up.

    Source: Montana Commercial Driver License Manual — Section 2.22.1, Alcohol and Driving

  4. 4. When does the manual tell night drivers to be especially alert for drunk drivers?

    Correct answer: Near the hours when bars and taverns close

    In its discussion of night roadway factors, the manual says drunk and drugged drivers are a hazard to you and to themselves, and that you should be especially watchful around closing time for bars and taverns.

    Source: Montana Commercial Driver License Manual — Section 2.11.3, Roadway Factors

  5. 5. The manual's 'Are You At Risk?' list says that getting how little sleep triples your risk?

    Correct answer: Six hours or less

    The first item on the list asks whether you are sleep-deprived or fatigued and notes that six hours of sleep or fewer makes your risk three times as high.

    Source: Montana Commercial Driver License Manual — Section 2.11.2, Driver Factors

  6. 6. Which three things does the manual say determine your blood alcohol concentration?

    Correct answer: How much you drink, how fast you drink, and your weight

    More alcohol and faster drinking both raise BAC, and body weight matters because a smaller person needs less alcohol to reach the same BAC.

    Source: Montana Commercial Driver License Manual — Section 2.22.1, Alcohol and Driving

  7. 7. A Montana CDL holder refuses a test requested under another state's implied consent law. How does Montana's list of major offenses treat that?

    Correct answer: It is a major offense, whether the refusal is in Montana or any other jurisdiction

    The first item on Montana's major offense list is a refusal to be tested under an implied consent law, whether Montana's or another jurisdiction's.

    Source: Montana Commercial Driver License Manual — Keeping Your Commercial Driver License

  8. 8. A doctor gives a commercial driver a drug. Under what condition does the manual say possessing and using it is permitted?

    Correct answer: When the doctor has told the driver it will not affect the ability to drive safely

    The manual allows a drug provided by a doctor only if the doctor informs the driver that safe driving ability will not be affected. It also says to heed warning labels and doctor's orders.

    Source: Montana Commercial Driver License Manual — Section 2.22.2, Other Drugs

  9. 9. On the manual's approximate BAC chart, before any adjustment for time, how do a 100-pound person and a 200-pound person compare after two drinks each?

    Correct answer: About .08 for the 100-pound person and .04 for the 200-pound person

    The two-drink row of the chart lists .08 under 100 pounds and .04 under 200 pounds, which shows why a smaller person reaches a given BAC on less alcohol.

    Source: Montana Commercial Driver License Manual — Section 2.22.1, Alcohol and Driving

  10. 10. Alcohol first affects the part of the brain that controls judgment and self-control. What does the manual call one of the bad things about that?

    Correct answer: It can prevent drinkers from realizing they are becoming drunk

    Because judgment goes first, the manual warns that drinkers may not know they are getting drunk, even though sound judgment and self-control are essential to safe driving.

    Source: Montana Commercial Driver License Manual — Section 2.22.1, Alcohol and Driving

  11. 11. The manual explains what a BAC of .10 means. What fraction of your total blood content is alcohol at that level?

    Correct answer: One-tenth of 1 percent, or 1/1000

    A note under the table of BAC effects says a BAC of .10 means 1/10 of 1% of your total blood content is alcohol.

    Source: Montana Commercial Driver License Manual — Section 2.22.1, Alcohol and Driving

  12. 12. What does the manual say about using caffeine to hold off fatigue?

    Correct answer: It can raise awareness for a few hours, but it wears off and should not be relied on

    The manual says caffeine may increase awareness for a few hours, warns against drinking too much, and tells drivers not to depend on it to prevent fatigue.

    Source: Montana Commercial Driver License Manual — Section 2.11.2, Driver Factors

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