CDL driving rules practice questions
20 free practice questions from 49 CFR Part 392. Each answer is explained and linked to the rule it comes from.
CDL Driving rules
20 questions across 8 topics. After each answer you see why it is right, with a link to the official source.
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Prefer to read? Here is every question in the CDL Driving rules set, grouped by topic. Open a question to see the answer, why it is right and the official source.
Alcohol prohibition
1. Under 392.5(a)(3), which possession of beer, wine or distilled spirits on a CMV is outside the prohibition?
- A. Alcohol manifested and transported as part of a shipment
- B. A sealed bottle kept in the driver's sleeper berth
- C. Alcohol the driver bought for use after the trip
- D. Alcohol kept unopened in the cab's glove box
Show answer
Answer: A. Alcohol manifested and transported as part of a shipment
The possession ban "does not apply to possession of wine, beer, or distilled spirits which are" either "Manifested and transported as part of a shipment" or "Possessed or used by bus passengers."
Source: eCFR: 49 CFR 392.5, Alcohol prohibition (as of Nov 3, 2026)
2. Under 392.5(b)(2), on what basis must a motor carrier not require or permit a driver to be on duty or operate a CMV when the driver appears to have used alcohol within the preceding four hours?
- A. Only a confirmed evidential breath test
- B. Only a written admission by the driver
- C. The driver's general appearance or conduct, or other substantiating evidence
- D. Only a police report
Show answer
Answer: C. The driver's general appearance or conduct, or other substantiating evidence
No motor carrier shall require or permit a driver to be on duty or operate a CMV "if, by the driver's general appearance or conduct or by other substantiating evidence, the driver appears to have used alcohol within the preceding four hours."
Source: eCFR: 49 CFR 392.5, Alcohol prohibition (as of Nov 3, 2026)
3. How may a driver who is subject to an out-of-service order under 392.5 seek review of that order?
- A. By calling the motor carrier's dispatcher within 24 hours
- B. By submitting a written petition for review within 10 days of issuance to the Division Administrator or State Director for the geographical area where the order was issued
- C. By retaking the CDL knowledge test
- D. By petitioning the State licensing agency within 90 days
Show answer
Answer: B. By submitting a written petition for review within 10 days of issuance to the Division Administrator or State Director for the geographical area where the order was issued
A driver "may petition for review of that order by submitting a petition for review in writing within 10 days of the issuance of the order to the Division Administrator or State Director for the geographical area in which the order was issued."
Source: eCFR: 49 CFR 392.5, Alcohol prohibition (as of Nov 3, 2026)
Ill or fatigued operator and drugs
4. Under 392.3, when may a driver whose alertness is so impaired by fatigue that driving is unsafe continue to operate a CMV?
- A. When fewer than 2 hours of driving time remain in the day
- B. When the dispatcher approves it by phone
- C. When the load is due at a scheduled appointment
- D. In a grave emergency where obeying the rule would increase the hazard, only to the nearest place at which that hazard is removed
Show answer
Answer: D. In a grave emergency where obeying the rule would increase the hazard, only to the nearest place at which that hazard is removed
Only "in a case of grave emergency where the hazard to occupants of the commercial motor vehicle or other users of the highway would be increased by compliance with this section" may the driver continue "to the nearest place at which that hazard is removed."
Source: eCFR: 49 CFR 392.3, Ill or fatigued operator (as of Nov 3, 2026)
5. The licensed medical practitioner exception in 392.4(c) covers paragraphs (a)(2), (3) and (4). Which substance category in 392.4(a) does it leave out?
- A. Amphetamines and their formulations
- B. Schedule I substances (21 CFR 1308.11)
- C. Narcotic drugs and their derivatives
- D. Other substances that could make the driver incapable of safe driving
Show answer
Answer: B. Schedule I substances (21 CFR 1308.11)
392.4(c) says "Paragraphs (a) (2), (3), and (4) do not apply" to a substance given under a licensed medical practitioner's instructions; paragraph (a)(1), "Any 21 CFR 1308.11 Schedule I substance," is not in that list.
Source: eCFR: 49 CFR 392.4, Drugs and other substances (as of Nov 3, 2026)
Railroad-highway grade crossings
6. Under 392.10(b)(5), who may erect the "Exempt" signs that mark an industrial or spur line railroad grade crossing where a stop need not be made?
- A. Only the appropriate State or local authority, or others with its consent
- B. The motor carrier whose trucks use the crossing
- C. Any driver who uses the crossing every day
- D. The shipper at the industrial site
Show answer
Answer: A. Only the appropriate State or local authority, or others with its consent
A stop need not be made at "An industrial or spur line railroad grade crossing marked with a sign reading “Exempt.” Such “Exempt” signs shall be erected only by or with the consent of the appropriate State or local authority."
Source: eCFR: 49 CFR 392.10, Railroad grade crossings; stopping required (as of Nov 3, 2026)
7. Which cargo tank motor vehicle does 392.10(a)(5) add to the CMVs that must stop before crossing railroad tracks at grade?
- A. One carrying any food-grade liquid
- B. One that is empty and has never carried hazardous material
- C. One carrying potable water
- D. One transporting a commodity which at the time of loading has a temperature above its flashpoint
Show answer
Answer: D. One transporting a commodity which at the time of loading has a temperature above its flashpoint
The list includes "Every cargo tank motor vehicle transporting a commodity which at the time of loading has a temperature above its flashpoint as determined by § 173.120 of this title."
Source: eCFR: 49 CFR 392.10, Railroad grade crossings; stopping required (as of Nov 3, 2026)
8. Under 392.10(b)(3), what kind of traffic control at a railroad grade crossing means a stop need not be made?
- A. A functioning highway traffic signal transmitting a green indication which, under local law, permits the CMV to proceed across the tracks without slowing or stopping
- B. A crossbuck sign with no lights or gates
- C. A yield sign posted before the crossing
- D. A flashing red signal at the crossing
Show answer
Answer: A. A functioning highway traffic signal transmitting a green indication which, under local law, permits the CMV to proceed across the tracks without slowing or stopping
A stop need not be made at "A railroad grade crossing controlled by a functioning highway traffic signal transmitting a green indication which, under local law, permits the commercial motor vehicle to proceed across the railroad tracks without slowing or stopping."
Source: eCFR: 49 CFR 392.10, Railroad grade crossings; stopping required (as of Nov 3, 2026)
9. What does 392.11 require of a CMV not listed in 392.10 as it approaches a railroad grade crossing?
- A. It may cross at the posted speed limit without slowing
- B. It must be driven at a speed that lets it stop before the nearest rail, and not cross until due caution shows the course is clear
- C. It must stop only between sunset and sunrise
- D. It must sound its horn and may then continue at speed
Show answer
Answer: B. It must be driven at a speed that lets it stop before the nearest rail, and not cross until due caution shows the course is clear
Such a CMV must "be driven at a rate of speed which will permit said commercial motor vehicle to be stopped before reaching the nearest rail" and must not cross "until due caution has been taken to ascertain that the course is clear."
Source: eCFR: 49 CFR 392.11, Railroad grade crossings; slowing down required (as of Nov 3, 2026)
Scope, schedules and hazardous conditions
10. Under 392.2, which rule must be complied with when an FMCSA regulation imposes a higher standard of care than the local law of the jurisdiction?
- A. The local law, because it is where the vehicle is operating
- B. Whichever rule is less strict
- C. The FMCSA regulation
- D. Whichever rule the motor carrier chooses
Show answer
Answer: C. The FMCSA regulation
A CMV is operated under local law, but "if a regulation of the Federal Motor Carrier Safety Administration imposes a higher standard of care than that law, ordinance or regulation, the Federal Motor Carrier Safety Administration regulation must be complied with."
Source: eCFR: 49 CFR 392.2, Applicable operating rules (as of Nov 3, 2026)
Stopped vehicles and warning devices
11. Under 392.22(a), besides the time before the warning devices are placed, when must the hazard warning signal flashers of a CMV stopped on the shoulder of a highway be used?
- A. Only when the stop lasts more than 1 hour
- B. Never; once the warning devices are out, the flashers must be turned off
- C. Only between sunset and sunrise
- D. During the time the warning devices are picked up for storage before the CMV is moved
Show answer
Answer: D. During the time the warning devices are picked up for storage before the CMV is moved
"The flashing signals shall be used during the time the warning devices are picked up for storage before movement of the commercial motor vehicle." They "may be used at other times while a commercial motor vehicle is stopped in addition to, but not in lieu of, the warning devices".
Source: eCFR: 49 CFR 392.22, Emergency signals; stopped commercial motor vehicles (as of Nov 3, 2026)
12. Under 392.22(b)(2)(iii), when must warning devices be placed for a CMV stopped within the business or residential district of a municipality?
- A. Always, within 10 minutes, as on any other highway
- B. Only when the stop lasts more than 1 hour
- C. During the time lighted lamps are required, when street or highway lighting is insufficient to make the CMV clearly discernable at a distance of 500 feet
- D. Never; warning devices are not used in municipalities
Show answer
Answer: C. During the time lighted lamps are required, when street or highway lighting is insufficient to make the CMV clearly discernable at a distance of 500 feet
"The placement of warning devices is not required within the business or residential district of a municipality, except during the time lighted lamps are required and when street or highway lighting is insufficient to make a commercial motor vehicle clearly discernable at a distance of 500 feet to persons on the highway."
Source: eCFR: 49 CFR 392.22, Emergency signals; stopped commercial motor vehicles (as of Nov 3, 2026)
13. A CMV equipped with only fusees is stopped on the shoulder of a highway. What does 392.22(b)(2)(i) require before the stopped CMV is moved?
- A. The fusees are left burning to warn traffic
- B. The fusees are moved 100 feet ahead of the CMV
- C. The driver extinguishes and removes each fusee
- D. Each fusee is replaced with a reflective triangle
Show answer
Answer: C. The driver extinguishes and removes each fusee
The driver places a lighted fusee at each prescribed location and "Before the stopped commercial motor vehicle is moved, the driver shall extinguish and remove each fusee."
Source: eCFR: 49 CFR 392.22, Emergency signals; stopped commercial motor vehicles (as of Nov 3, 2026)
14. Gasoline is leaking from a CMV stopped upon a highway. What does 392.22(b)(2)(vi) say about flame-producing emergency signals?
- A. None may be lighted or placed except at such a distance from the liquid as will assure the prevention of a fire or explosion
- B. They must be placed right beside the leak to mark it
- C. They must be used in place of reflective triangles
- D. They may be used only within 10 feet of the CMV
Show answer
Answer: A. None may be lighted or placed except at such a distance from the liquid as will assure the prevention of a fire or explosion
If gasoline or another flammable liquid leaks, "no emergency warning signal producing a flame shall be lighted or placed except at such a distance from any such liquid or gas as will assure the prevention of a fire or explosion."
Source: eCFR: 49 CFR 392.22, Emergency signals; stopped commercial motor vehicles (as of Nov 3, 2026)
15. For which of these vehicles does 392.25 forbid flame-producing emergency signals?
- A. Any CMV stopped during daylight hours
- B. A bus transporting passengers
- C. A CMV transporting Division 1.4 explosives
- D. A CMV using compressed gas as a motor fuel
Show answer
Answer: D. A CMV using compressed gas as a motor fuel
392.25 bars flame-producing signals for "any commercial motor vehicle using compressed gas as a motor fuel"; for explosives it names only "Division 1.1, Division 1.2, or Division 1.3."
Source: eCFR: 49 CFR 392.25, Flame producing devices (as of Nov 3, 2026)
Seat belts, fueling and other practices
16. Under 392.16(b), in which vehicle must all other occupants be properly restrained by seat belts before the driver operates it?
- A. Only a vehicle hauling hazardous materials
- B. A property-carrying CMV that has seat belt assemblies installed at the seats for other occupants
- C. Only a vehicle traveling on an interstate highway
- D. Only a vehicle whose occupants are motor carrier employees
Show answer
Answer: B. A property-carrying CMV that has seat belt assemblies installed at the seats for other occupants
392.16(b) applies to "a property-carrying commercial motor vehicle" that "has seat belt assemblies installed at the seats for other occupants of the vehicle" and requires that "all other occupants are properly restrained."
Source: eCFR: 49 CFR 392.16, Use of seat belts (as of Nov 3, 2026)
17. When does 392.50(a) allow a CMV to be fueled with the engine running?
- A. When the outside temperature is below freezing
- B. When fueling will take less than 5 minutes
- C. Whenever a second person watches the nozzle
- D. When it is necessary to run the engine to fuel the commercial motor vehicle
Show answer
Answer: D. When it is necessary to run the engine to fuel the commercial motor vehicle
No driver or employee shall "Fuel a commercial motor vehicle with the engine running, except when it is necessary to run the engine to fuel the commercial motor vehicle".
Source: eCFR: 49 CFR 392.50, Ignition of fuel; prevention (as of Nov 3, 2026)
Texting and hand-held mobile telephones
18. Besides the ban on drivers in 392.80(a), what duty does 392.80(b) place on motor carriers?
- A. A motor carrier shall not allow or require its drivers to engage in texting while driving
- B. A motor carrier must install texting-blocking software on each driver's phone
- C. A motor carrier must report each driver's texting to the State licensing agency
- D. A motor carrier must collect drivers' phones before each trip
Show answer
Answer: A. A motor carrier shall not allow or require its drivers to engage in texting while driving
392.80(b) is headed "Motor carriers" and states: "No motor carrier shall allow or require its drivers to engage in texting while driving."
Source: eCFR: 49 CFR 392.80, Prohibition against texting (as of Nov 3, 2026)
19. Under the definition in 392.82(b), which of these counts as driving for the hand-held mobile telephone rule?
- A. Halted at the side of the highway in a location where the vehicle can safely remain stationary
- B. Halted off the highway at a rest area where the vehicle can safely remain stationary
- C. Operating a CMV on a highway while temporarily stationary because of traffic
- D. Halted off the highway at a fuel island where the vehicle can safely remain stationary
Show answer
Answer: C. Operating a CMV on a highway while temporarily stationary because of traffic
Driving means "operating a commercial motor vehicle on a highway, including while temporarily stationary because of traffic," but not after the driver "has moved the vehicle to the side of, or off, a highway and has halted in a location where the vehicle can safely remain stationary."
Source: eCFR: 49 CFR 392.82, Using a hand-held mobile telephone (as of Nov 3, 2026)
Equipment and cargo inspection
20. Which driver does 392.9(b)(4) exempt from the cargo inspection rules in 392.9(b)?
- A. Any driver on a trip shorter than 150 miles
- B. The driver of a sealed CMV who has been ordered not to open it to inspect its cargo
- C. Any driver of a flatbed trailer
- D. Any driver hauling cargo that someone else loaded
Show answer
Answer: B. The driver of a sealed CMV who has been ordered not to open it to inspect its cargo
"The rules in this paragraph (b) do not apply to the driver of a sealed commercial motor vehicle who has been ordered not to open it to inspect its cargo or to the driver of a commercial motor vehicle that has been loaded in a manner that makes inspection of its cargo impracticable."
Source: eCFR: 49 CFR 392.9, Inspection of cargo, cargo securement devices and systems (as of Nov 3, 2026)