California CDL — General Knowledge: Alcohol & Drugs Practice Test

Question 1

What blood alcohol concentration (BAC) makes it illegal to operate a commercial vehicle?

Accepted Answer

0.04 or higher — It is illegal to drive a commercial vehicle with a BAC of 0.04 or higher, which is stricter than the 0.08 limit for regular drivers. Even smaller amounts of alcohol impair driving skills.

Answer

0.08 or higher

Answer

0.10 or higher

Answer

There is no limit for CDL holders

Question 2

When may a commercial driver lawfully use a drug that a physician has prescribed for them?

Accepted Answer

When the physician has said it will not affect their ability to drive safely — A prescription on its own is not enough. The doctor has to state that the medication will not impair the driver's safe driving ability, and the driver still has to heed the warning labels on anything they take.

Answer

Whenever the prescription is current and written in the driver's own name

Answer

Whenever the dose is taken at the very end of a shift

Answer

Never — any prescription drug at all bars a driver from the wheel

Question 3

Which statement about a beer, a glass of table wine, and a shot of hard liquor is TRUE?

Accepted Answer

In standard measures each one delivers about the same amount of alcohol — A twelve-ounce beer, a five-ounce pour of table wine, and a shot and a half of eighty proof liquor are equivalent servings. What matters to your body is the alcohol itself, not the container it arrived in.

Answer

Beer is the mildest of the three and can be treated as harmless

Answer

Wine leaves the body faster than the other two

Answer

Only the liquor counts against a commercial driver

Question 4

How long before reporting for duty must a commercial driver stop consuming any intoxicating beverage?

Accepted Answer

Four hours — Drinking while on duty is never permitted, and the four-hour window before you go on duty is closed as well. The rule covers any intoxicating drink no matter how weak it happens to be.

Answer

One hour

Answer

Two hours

Answer

Eight hours

Question 5

How does alcohol affect your ability to drive?

Accepted Answer

It slows reactions and impairs judgment, coordination, and vision — Alcohol slows your reactions and impairs your judgment, coordination, and vision. These are exactly the skills you need to control a large vehicle safely, so any amount raises crash risk.

Answer

It sharpens reactions in experienced drivers

Answer

It affects only your sense of smell

Answer

It has no effect below the legal limit

Question 6

A driver has had several drinks. Which of these will actually bring the blood alcohol level back down?

Accepted Answer

Waiting, because the liver clears alcohol at a fixed and fairly slow rate — The liver works through roughly a third of an ounce of alcohol each hour and cannot be hurried. Coffee, cold water, and food may make somebody feel sharper without changing how much alcohol is still in the blood.

Answer

Strong black coffee

Answer

A cold shower

Answer

A large meal followed by some exercise

Question 7

Which statement about other drugs and medicines is TRUE for a commercial driver?

Accepted Answer

Prescription and over-the-counter drugs can impair driving — Many prescription and over-the-counter drugs can impair driving, so read labels and check with a doctor before driving. Never use stimulants or "pep pills" to try to stay awake behind the wheel.

Answer

Only illegal drugs can impair driving

Answer

Over-the-counter medicines are always safe to drive on

Answer

Stimulant pills are a safe way to fight fatigue

Question 8

A roadside test shows a driver has alcohol in their system, but at a level below 0.04 percent. What happens next?

Accepted Answer

The driver is placed out of service for a full 24 hours — Any detectable alcohol beneath the 0.04 threshold still triggers a twenty-four hour out-of-service order. The commercial standard leaves no room for a small amount that would pass unnoticed in a private car.

Answer

Nothing, because the reading falls under the commercial limit

Answer

The CDL is revoked for one year

Answer

The driver may continue after a one-hour rest break

Question 9

Under the "implied consent" rule, what have you agreed to by driving a commercial vehicle?

Accepted Answer

You have agreed to be tested for alcohol or drugs — By driving a commercial vehicle, you have consented to be tested for alcohol or drugs. Refusing to be tested carries the same kind of penalty as failing the test, including disqualification.

Answer

You may refuse any test without penalty

Answer

You give up your right to a license appeal

Answer

You must carry alcohol test kits in the cab

Question 10

Which combination of factors decides how high a person's blood alcohol concentration will climb?

Accepted Answer

How much is drunk, how fast it is drunk, and the drinker's body weight — Three things drive the number: the total alcohol taken in, the speed at which it goes down, and the body weight it is diluted into. A lighter person reaches any given level on noticeably less.

Answer

The proof of the drink and how recently the person ate

Answer

The person's height and how much sleep they had

Answer

The brand of the drink and the temperature of the room

California CDL — General Knowledge: Alcohol & Drugs practice test

Study questions with answers

1. What blood alcohol concentration (BAC) makes it illegal to operate a commercial vehicle?

2. When may a commercial driver lawfully use a drug that a physician has prescribed for them?

3. Which statement about a beer, a glass of table wine, and a shot of hard liquor is TRUE?

4. How long before reporting for duty must a commercial driver stop consuming any intoxicating beverage?

5. How does alcohol affect your ability to drive?

6. A driver has had several drinks. Which of these will actually bring the blood alcohol level back down?

7. Which statement about other drugs and medicines is TRUE for a commercial driver?

8. A roadside test shows a driver has alcohol in their system, but at a level below 0.04 percent. What happens next?

9. Under the "implied consent" rule, what have you agreed to by driving a commercial vehicle?

10. Which combination of factors decides how high a person's blood alcohol concentration will climb?

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