Alabama CDL — General Knowledge practice
Alabama 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
12 questions · pass with 10 correct. You get instant feedback and an explanation after every answer.
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.
Show all 12 questions with answers
1. If you become too ill to drive safely, you should:
Correct answer: Not drive, except to reach the nearest safe stopping point in an emergency
When illness makes safe operation impossible you must not drive, other than reaching a safe place to stop in a true emergency.
2. Combining other drugs with alcohol tends to:
Correct answer: Make the effects of the drugs much worse
Alcohol can greatly amplify the effects of other drugs, so mixing any drug with driving is unsafe.
Source: Alabama CDL Manual - Section 2.22.2 (Alcohol, Other Drugs, and Driving - Other Drugs)
3. After alcohol passes through the brain, most of the remainder is carried to the:
Correct answer: Liver, which processes it at a fixed rate
A small share leaves through urine, sweat, and breath, but most alcohol goes to the liver, which breaks it down slowly.
Source: Alabama CDL Manual - Section 2.22 (Alcohol, Other Drugs, and Driving - How Alcohol Works)
4. What blood alcohol concentration makes it illegal to operate a commercial vehicle?
Correct answer: 0.04 percent or higher
The commercial limit is 0.04 percent - stricter than the usual 0.08 percent for non-commercial drivers.
Source: Alabama CDL Manual - Section 2.22 (Alcohol, Other Drugs, and Driving)
5. Which statement about a 'standard drink' is correct?
Correct answer: A beer, a glass of wine, and a shot of liquor contain similar amounts of alcohol
It is the alcohol that impairs you, and a typical beer, glass of wine, and shot of liquor each contain about the same amount.
Source: Alabama CDL Manual - Section 2.22 (Alcohol, Other Drugs, and Driving - What Is a Drink)
6. What should a driver do about a drug that only hides fatigue?
Correct answer: Avoid it, because rest is the only real cure for fatigue
Drugs that merely mask tiredness are dangerous; only sleep genuinely relieves fatigue.
Source: Alabama CDL Manual - Section 2.22.2 (Alcohol, Other Drugs, and Driving - Other Drugs)
7. Alcohol impairs which of the following abilities needed for driving?
Correct answer: Judgment, vision, coordination, and reaction time
Drinking affects judgment, vision, coordination, and reaction time, leading to errors like weaving and slow responses.
8. Roughly how much alcohol can the liver process in one hour?
Correct answer: About one-third of an ounce
The liver clears only about one-third ounce of alcohol per hour - far less than a single standard drink holds - so it builds up if you drink faster.
Source: Alabama CDL Manual - Section 2.22 (Alcohol, Other Drugs, and Driving - How Alcohol Works)
9. What commonly measures the amount of alcohol in a person's body?
Correct answer: Blood alcohol concentration (BAC)
BAC is the standard measure of how much alcohol is in the body and rises when you drink faster than the liver can process it.
Source: Alabama CDL Manual - Section 2.22 (Alcohol, Other Drugs, and Driving - How Alcohol Works)
10. What will actually sober up a person who has been drinking?
Correct answer: Only the passage of time
The liver removes alcohol at a fixed rate, so only time - not coffee or a shower - lowers your BAC.
Source: Alabama CDL Manual - Section 2.22 (Alcohol, Other Drugs, and Driving - How Alcohol Works)
11. How much alcohol does it take to begin impairing some drivers?
Correct answer: As little as one drink
For some people even a single drink is enough to show signs of impairment.
Source: Alabama CDL Manual - Section 2.22 (Alcohol, Other Drugs, and Driving)
12. By operating a commercial vehicle, a driver is considered to have consented to:
Correct answer: Alcohol testing
Driving a CMV means you have given implied consent to alcohol testing.
More CDL — General Knowledge topics
Practice Alcohol & Drugs in another state
Every Alabama question is written from the official Alabama driver handbook and checked against its current edition. DMV Test Free is a free, independent study resource — not affiliated with any DMV or government agency. About DMV Test Free