Alcohol & Drugs

Study questions with answers

10 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. 1. By operating on Illinois highways, a commercial driver has legally agreed to do what?

   Correct answer: Submit to chemical testing for blood-alcohol concentration

   Under the state's implied-consent rule, anyone driving on public roads has already consented to chemical testing that measures blood-alcohol concentration if lawfully requested. Refusing that testing carries its own disqualification.

   Source: Illinois CDL Guide — Sec. 1.5, Alcohol/Drug Regulations

2. 2. A driver refuses to take a chemical test for alcohol when lawfully asked. What is the minimum disqualification period?

   Correct answer: 12 months

   Refusing a lawful chemical test, or testing above the legal limit, disqualifies the driver for no less than one year — the same minimum that applies to a DUI conviction.

   Source: Illinois CDL Guide — Sec. 1.5, Disqualifications

3. 3. How does a DUI conviction affect a driver who was hauling placarded hazardous materials at the time?

   Correct answer: Disqualified for at least three years

   A DUI or a refusal to test normally means at least a one-year disqualification, but if it happens while the driver is transporting placarded hazardous materials, the minimum jumps to three years.

   Source: Illinois CDL Guide — Sec. 1.5, Disqualifications

4. 4. Driving a commercial vehicle with any amount of an illegal drug or cannabis in your system results in what minimum penalty?

   Correct answer: A disqualification of at least 12 months

   A conviction for operating a commercial vehicle with any unlawful controlled substance or cannabis present carries a disqualification of at least one year, mirroring the alcohol-related penalties.

   Source: Illinois CDL Guide — Sec. 1.5, Disqualifications

5. 5. A CDL holder is driving their personal car, not a commercial vehicle. At what blood-alcohol level are they considered legally impaired?

   Correct answer: 0.08 percent

   When a CDL holder is behind the wheel of a non-commercial vehicle, the ordinary 0.08 percent limit applies. The stricter 0.04 threshold only governs the operation of a commercial vehicle.

   Source: Illinois CDL Guide — Sec. 1.5, Alcohol/Drug Regulations

6. 6. How should fatigue be treated compared with alcohol impairment behind the wheel?

   Correct answer: As a serious impairment that raises crash risk

   Tiredness raises your crash risk and grows worse at night. Like alcohol, it dulls your abilities, and the only safe fix is to stop and sleep.

   Source: Illinois CDL Guide — Sec. 2.23, Staying Alert and Fit

7. 7. What effect does carbon monoxide have that makes a leaking exhaust dangerous?

   Correct answer: It makes you sleepy

   Carbon monoxide gas makes you sleepy, so a leak can gradually put a driver to sleep without warning. That is why a broken exhaust system must be repaired before driving.

   Source: Illinois CDL Guide — Sec. 2.13, Driving in Winter

8. 8. What blood-alcohol level is a school bus driver allowed to have while operating a school bus?

   Correct answer: None — the limit is 0.00 percent

   A school bus driver must have essentially no measurable alcohol in their system; the manual sets the limit at 0.00 percent for anyone driving a school bus, which is stricter than the general CDL standard.

   Source: Illinois CDL Guide — Sec. 1.5, Alcohol/Drug Regulations

9. 9. Beyond alcohol, which of the following makes a driver a hazard the manual warns about?

   Correct answer: A driver who is sleepy, on drugs, or ill

   A driver who is drowsy, using drugs, or sick is just as much a hazard as one who has been drinking. Watch for impaired and sleepy drivers, especially late at night.

   Source: Illinois CDL Guide — Sec. 2.8, Seeing Hazards

10. 10. What is the lowest blood-alcohol concentration at which an Illinois CDL holder is prohibited from operating a commercial motor vehicle?

    Correct answer: 0.04 percent

    State law bars a CDL holder from driving a commercial vehicle once their blood-alcohol level reaches 0.04 percent. That threshold is half the 0.08 limit that applies to ordinary passenger-vehicle drivers.

    Source: Illinois CDL Guide — Sec. 1.5, Alcohol/Drug Regulations