Ohio CDL — General Knowledge practice
Alcohol & Drugs
Blood alcohol limits, zero-tolerance and implied-consent laws, and how alcohol and drugs — legal or not — affect your driving.
Questions reviewed against the official Ohio driver handbook · July 7, 2026
11 questions · pass with 9 correct. You get instant feedback and an explanation after every answer.
Study questions with answers
11 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. If a driver has any measurable alcohol below 0.04 percent, what happens?
Correct answer: The driver is placed out of service for 24 hours
Any detectable amount of alcohol under 0.04 percent puts the driver out of service for 24 hours rather than triggering a full disqualification.
Source: Ohio CDL Driver Manual, Section 1 (Disqualifications)
2. For a first offense such as driving a CMV with a BAC of 0.04 or more, how long will you lose your CDL?
Correct answer: At least one year
A first major offense costs you your CDL for at least one year. That penalty grows to at least three years if you were hauling placarded hazardous materials.
Source: Ohio CDL Driver Manual, Section 1 (Disqualifications)
3. At what blood alcohol concentration does it become illegal to operate a commercial motor vehicle?
Correct answer: 0.04 percent or higher
Operating a CMV is illegal at a blood alcohol concentration of 0.04 percent or higher, a stricter limit than the one that applies to most passenger-car drivers.
Source: Ohio CDL Driver Manual, Section 1 (Alcohol Disqualifications)
4. By operating a commercial motor vehicle, a driver is considered to have agreed to what?
Correct answer: Testing for alcohol when required
Driving a CMV is treated as giving your consent to alcohol testing. Refusing to be tested is itself a disqualifying offense.
Source: Ohio CDL Driver Manual, Section 1 (Alcohol Disqualifications)
5. What is the only thing that will actually lower a drinker's blood alcohol concentration?
Correct answer: Letting enough time pass
Because the liver processes alcohol at a steady rate, only the passage of time reduces your level. Black coffee, food, or a cold shower will not speed it up.
Source: Ohio CDL Driver Manual, Section 2 (How Alcohol Works)
6. As blood alcohol rises, which ability is affected first?
Correct answer: Judgment and self-control
Alcohol first hits the part of the brain that governs judgment and self-control. That is dangerous because it can keep drinkers from realizing they are getting drunk.
Source: Ohio CDL Driver Manual, Section 2 (Alcohol and the Brain)
7. Which factors together determine a person's blood alcohol concentration?
Correct answer: The amount consumed, the speed of drinking, and body weight
How much you drink, how quickly you drink it, and your body weight all shape your BAC. A lighter person reaches a given level on less alcohol.
Source: Ohio CDL Driver Manual, Section 2 (What Determines BAC?)
8. A standard drink of beer, wine, or hard liquor is best described how?
Correct answer: A beer, a glass of wine, and a shot of liquor hold about the same alcohol
A 12-ounce beer, a 5-ounce glass of table wine, and a 1.5-ounce shot of 80-proof liquor each contain the same amount of alcohol. It is the alcohol, not the type, that matters.
Source: Ohio CDL Driver Manual, Section 2 (What Is a Drink?)
9. If a first major alcohol or drug offense happens while you drive a vehicle placarded for hazardous materials, the CDL loss is at least how long?
Correct answer: Three years
The minimum disqualification jumps to three years when the offense occurs in a vehicle carrying placarded hazardous materials.
Source: Ohio CDL Driver Manual, Section 1 (Disqualifications)
10. What is the only genuine cure for fatigue while driving?
Correct answer: Getting sleep and rest
Rest and sleep are the only real remedy for fatigue. Drugs that mask tiredness may keep you awake but do not restore true alertness.
Source: Ohio CDL Driver Manual, Section 2 (Other Drugs)
11. What should you know about common over-the-counter cold medicines before driving?
Correct answer: They can cause drowsiness and impair safe driving
Many legal cold and allergy medicines can make a driver drowsy or otherwise unsafe. Heed the warning labels, and never assume a non-prescription drug is harmless behind the wheel.
Source: Ohio CDL Driver Manual, Section 2 (Other Drugs)
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Every Ohio question is written from the official Ohio 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