Alcohol, Drugs & DUI
Understand how alcohol and drugs destroy driving judgment and what follows.
Impairment questions are less about memorizing numbers and more about understanding what alcohol and drugs actually remove: judgment first, then reaction time, then coordination. Study how impairment builds, why self-assessment fails, and what consequences follow a violation, so the exam's scenario questions become predictable, because the impaired choice is always the one that felt fine at the time.
The rules that matter
- 0.08% BAC is the general adult limit, but you can be arrested below it if you are actually impaired.
- Zero-tolerance laws set a near-zero limit for drivers under 21 in every state.
- Only time lowers your BAC. Coffee, food, a cold shower, and fresh air do nothing.
- Implied consent means driving already counts as agreeing to chemical testing — refusing suspends your license by itself, before any conviction.
- Prescription and over-the-counter medicines can impair you enough to be charged with DUI.
- Alcohol impairs judgment before it impairs coordination, so impairment starts before it feels like it has.
The lessons in this module
Each lesson is one short set of questions. If you've missed questions in this module before, a few come back at the start. Progress saves automatically; sign in only if you want cross-device sync.
Lesson videos
4 lessons · See all →Read this in the handbook
Look for these sections: Alcohol and Drugs, Impaired Driving.
Where these rules come from
We do not copy official handbooks — most states do not allow it. What we do instead: state the rule in our own words, then name the official document behind it. 138 questions in this module cite 86 official documents, none checked earlier than 2026-05-17. The 6 most-cited are below.
| Official document | Sections cited |
|---|---|
NHTSA Risky Driving ↗ National · Checked 2026-08-01 | Impaired Driving |
NHTSA Drunk Driving ↗ National · Checked 2026-08-01 | Alcohol and Driving |
California Driver's Handbook ↗ State-specific · Checked 2026-07-28 | Alcohol Absorption Factors, Alcohol Myths, Alcohol and Impairment Factors |
California Driver's Handbook ↗ State-specific · Checked 2026-05-17 | Section 9: Alcohol and Drugs, Section 9: Alcohol and Drugs - Blood Alcohol Concentration Limits |
California Driver's Handbook ↗ State-specific · Checked 2026-08-17 | Section 5: An Introduction to Driving - Fatigue and Drowsiness, Section 5: An Introduction to Driving - Health, Fatigue, Medications, and Alertness, Section 5: An Introduction to Driving - Physical and Mental Alertness |
California Driver's Handbook ↗ State-specific · Checked 2026-05-17 | General Driving |
Opening a source takes you to the agency's own site, never to a copy of ours. If a source is out of date or broken, say so from any question.
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Review these questions
Which of the following factors does NOT affect how quickly you absorb alcohol?
- A. The color of the alcoholic beverage
- B. Whether you have eaten recently
- C. Your body weight
- D. How quickly you are drinking
Show answer
A. The color of the alcoholic beverage — The color of a drink has no effect on alcohol absorption. Factors that do affect it include body weight, food in the stomach, the rate of consumption, and individual metabolism.
Universal rule · checked against NHTSA Drunk Driving — Alcohol and Driving · verified 2026-08-01
'Drugged driving' refers to:
- A. Driving while carrying illegal drugs in the vehicle
- B. Only driving after using illegal narcotics, not legal medications or alcohol
- C. Driving after taking more than the prescribed dose of medication
- D. Operating a vehicle while impaired by any substance, including prescription or over-the-counter drugs
Show answer
D. Operating a vehicle while impaired by any substance, including prescription or over-the-counter drugs — Drugged driving means operating a vehicle while impaired by any substance — legal or illegal — that affects your ability to drive safely. This includes marijuana, opioids, sedatives, and even some antihistamines.
Universal rule · checked against NHTSA Risky Driving — Impaired Driving · verified 2026-08-01
'Drunk driving' and 'impaired driving' are different because:
- A. Drunk driving is more serious
- B. Impaired driving covers any substance that affects your driving
- C. They are the same thing
- D. Impaired driving only applies to prescription drugs
Show answer
B. Impaired driving covers any substance that affects your driving — 'Impaired driving' is the broader term covering any substance — alcohol, illegal drugs, prescription or over-the-counter medication — that reduces your ability to drive safely.
Universal rule · checked against NHTSA Drunk Driving — Alcohol and Driving · verified 2026-08-01
Which of the following statements about alcohol and driving is TRUE?
- A. Alcohol only impairs driving above the legal BAC limit
- B. One drink has no measurable effect on most adults
- C. Coffee can quickly reverse alcohol impairment
- D. Even small amounts of alcohol can impair judgment and reaction time
Show answer
D. Even small amounts of alcohol can impair judgment and reaction time — Alcohol impairs judgment, vision, and reaction time starting with the very first drink, well before reaching the legal BAC limit. There is no safe threshold for alcohol and driving.
Universal rule · checked against NHTSA Risky Driving — Impaired Driving · verified 2026-08-01
A driver who takes a prescription medication that causes drowsiness should:
- A. Drive only on familiar roads
- B. Not drive until they know how the medication affects them
- C. Drive only during daylight hours
- D. Drink extra coffee to stay alert
Show answer
B. Not drive until they know how the medication affects them — Prescription medications that cause drowsiness, dizziness, or blurred vision can impair driving as much as alcohol. Always read labels and consult your doctor or pharmacist before driving.
Universal rule · checked against NHTSA Risky Driving — Impaired Driving · verified 2026-08-01