A low-air pressure warning device that drops a flag in front of the driver

Gross Combination Weight Rating

AZ · GK Endorsement

Arizona General Knowledge CDL Practice Test

Below are 25 exam-style questions for the Arizona General Knowledge CDL knowledge test, modeled on the FMCSA-aligned content used by the Arizona Department of Transportation MVD. Try to answer each question on your own before reading the answer key directly under it. The questions and answer choices are shuffled deterministically per state and endorsement, so the order will stay the same on repeat visits — that lets you genuinely measure your improvement.

Heads up: this is a study tool, not a graded exam. Cover the answer with your hand or a sheet of paper for an honest practice run, then re-read the explanations for any questions you missed. Aim for 22 out of 25 or better, three times in a row, before scheduling the real exam.

Question 1 of 25

When approaching a railroad crossing in a CMV that is not required to stop, you should:

A Cross at maximum speed to get over quickly
B Always come to a full stop regardless of traffic
C Slow down, look, listen, and be prepared to stop
D Honk and proceed

Correct answer: C

Even when not required by class to stop, you must always be prepared to stop. Buses, hazmat, and certain other vehicles must stop every time.

Question 2 of 25

Which of the following is the correct order for the seven-step pre-trip air-brake check (last steps shown)?

A Test only the air-leak rate
B Test the service brake then the parking brake
C Test the parking brake then the service brake
D Test the low-air warning then drive

Correct answer: C

In the standard FMCSA seven-step procedure, the parking brake is tested before pulling away, then the service brake stop is the final step.

Question 3 of 25

A Class C CDL is required to drive:

A Class A combinations only
B Any vehicle over 26,001 lbs
C Vehicles designed to carry 16+ passengers including the driver, or that require hazmat placards
D Tractor-trailers under 26,001 lbs GCWR

Correct answer: C

Class C covers vehicles that don't meet Class A or B but are designed to carry 16 or more passengers (including the driver) or carry placarded amounts of hazardous materials.

Question 4 of 25

You are driving on a two-lane road and you see a driver about to pull out from a side road. You should:

A Honk and accelerate
B Maintain speed
C Move to the right lane
D Cover the brake and slow down

Correct answer: D

Anticipate the worst-case behavior. Cover the brake — keeping your foot just over it — so you can react if they pull out.

Question 5 of 25

The proper response to a tire blowout on the front axle is to:

A Shift to neutral and coast
B Steer sharply toward the shoulder
C Brake immediately and pull off the road
D Hold the steering wheel firmly, ease off the accelerator, and let the vehicle slow down

Correct answer: D

Hard braking after a blowout can cause loss of control. Hold the wheel, release the accelerator, and let speed bleed off before braking gently.

Question 6 of 25

A leaking exhaust system is dangerous because:

A It can let poisonous carbon monoxide into the cab
B It causes the engine to overheat
C It is illegal
D It increases fuel use

Correct answer: A

Carbon monoxide from a leaking exhaust can cause headaches, drowsiness, and unconsciousness. The illegality is real but the safety risk is the bigger answer.

Question 7 of 25

The proper following distance for a 60-foot truck traveling under 40 mph is at least:

A 6 seconds
B 10 seconds
C 1 second
D 4 seconds

Correct answer: A

Use one second per 10 feet of vehicle length below 40 mph: 60 ft / 10 = 6 seconds. Add one additional second above 40 mph.

Question 8 of 25

Which of the following is a valid reason to refuse a load?

A It would push your weight over legal limits
B All of the above
C The cargo is not properly secured or placarded
D It would make you exceed federal hours-of-service rules

Correct answer: B

A driver is required by federal law to refuse loads that violate HOS, weight, or hazmat rules. The driver, not the dispatcher, is liable.

Question 9 of 25

Which of the following is a sign of fatigue?

A Frequent yawning
B Trouble remembering the last few miles
C All of the above
D Drifting in your lane

Correct answer: C

All three are classic fatigue indicators in the FMCSA model. Cold air, music, and caffeine are not effective fixes — only sleep is.

Question 10 of 25

A driver must report any accident involving a CMV to the carrier within:

A 7 days
B 1 hour
C A reasonable time, before going off duty
D 24 hours

Correct answer: C

FMCSA rules require notification of the motor carrier in a reasonable time — most policies treat that as before going off duty.

Question 11 of 25

When backing a heavy vehicle, you should:

A Back to the right whenever possible
B Back without using mirrors so you can watch out the window
C Use a helper and walk around the vehicle first
D Back fast to get it over with

Correct answer: C

Always GOAL — Get Out And Look — and use a helper. Backing to the left when possible is preferred because you can see better, not to the right.

Question 12 of 25

A driver may keep moving when:

A A trailer brake light is out
B A vehicle is in safe operating condition
C Required emergency equipment is missing
D A passenger door is open

Correct answer: B

Federal rules forbid driving any CMV that is not in safe operating condition. Continue only after the defect is fixed.

Question 13 of 25

The minimum tread depth for steer-axle tires is:

A 6/32 inch
B 4/32 inch
C 2/32 inch
D 1/32 inch

Correct answer: B

Steer tires must have at least 4/32 inch in every major groove. Other tires require at least 2/32 inch.

Question 14 of 25

Stab braking is used:

A On wet roads only
B On vehicles with ABS
C On vehicles without ABS, to keep them straight in an emergency
D To save fuel

Correct answer: C

Stab braking — full application then release as soon as wheels lock, then re-apply — is for non-ABS vehicles. With ABS, do not pump.

Question 15 of 25

A driver's blood-alcohol concentration (BAC) of 0.04% or higher while operating a commercial motor vehicle is:

A Allowed off-duty only
B Allowed if the driver feels fine
C A traffic violation, but not a CDL disqualification
D Considered driving under the influence for CDL purposes

Correct answer: D

Federal rules treat 0.04% BAC in a CMV as DUI for CDL purposes — half the typical 0.08% limit for non-commercial drivers.

Question 16 of 25

A driver convicted of a major offense (DUI, leaving the scene, etc.) in a CMV faces:

A CDL disqualification for at least one year for a first offense
B A fine only
C A warning
D No federal consequence

Correct answer: A

Major offenses carry a one-year CDL disqualification minimum (three years if hauling hazardous materials), and lifetime for a second.

Question 17 of 25

When approaching a steep downgrade, the basic safe-driving rule is:

A Coast in neutral
B Stay in high gear
C Select a lower gear before starting down
D Use the parking brake intermittently

Correct answer: C

Get into a low gear before the descent so the engine helps hold the vehicle back.

Question 18 of 25

Which is true about brake lining wear and adjustment?

A Brake adjustment is the dispatcher's responsibility
B Slack adjusters need periodic checking; pushrod travel beyond limits is out-of-service
C Brakes self-adjust forever
D Drum brakes never need adjustment

Correct answer: B

Slack adjusters can fail, and pushrod travel must be within limits. Drivers check; adjustment itself is a maintenance task for qualified personnel.

Question 19 of 25

Cargo that hangs more than 4 feet beyond the back of the vehicle must be marked with:

A A green flag
B Yellow tape only
C Nothing — federal rules do not require marking
D A red flag (or red light at night) at the extreme rear

Correct answer: D

Federal rules require a red flag during the day and red lights at night for projecting cargo beyond 4 feet.

Question 20 of 25

A "wig-wag" is:

A A type of cargo strap
B A low-air pressure warning device that drops a flag in front of the driver
C A fuel-saving switch
D A trailer hitch component

Correct answer: B

On older trucks, a wig-wag is a mechanical low-air warning that lowers a flag into the driver's field of view when air pressure drops below safe limits.

Question 21 of 25

What is the most important reason for doing a vehicle inspection?

A To improve fuel economy
B Safety for yourself and other road users
C To reduce tire wear
D To meet your dispatcher's schedule

Correct answer: B

Federal rules and the FMCSA model manual list safety as the single most important reason for a pre-trip inspection. Mechanical defects discovered before the trip cannot kill anyone on the highway.

Question 22 of 25

You may not drive a CMV with a blood-alcohol concentration of:

A 0.08% or higher
B 0.10% or higher
C Any detectable amount above 0.00%
D 0.04% or higher

Correct answer: D

0.04% is the regulatory limit for CMV operation. A detectable amount under that triggers an out-of-service order but is not necessarily a DUI conviction.

Question 23 of 25

GCWR stands for:

A Gross Cargo Weight Rating
B General Carrier Weight Rating
C Gross Combination Weight Rating
D Government Combination Weight Reading

Correct answer: C

GCWR is the maximum allowable weight of a power unit plus a towed unit, including all cargo. It determines whether a license is Class A.

Question 24 of 25

Which is true about the use of turn signals?

A Use the four-way flashers instead of signals at intersections
B Signal early, signal continuously, and cancel after the turn
C Signal only when other vehicles are present
D Signal only at the moment you start turning

Correct answer: B

The federal model manual specifies signal early, continuously, and cancel after — the same three steps every state CDL test asks about.

Question 25 of 25

On a long downgrade, why is it dangerous to use the brakes too much?

A It wastes brake pads
B It triggers the ABS warning light
C It cools the brakes too much
D Brake fade can leave you with reduced or no braking power

Correct answer: D

Heat from continuous braking causes the friction surfaces to lose their grip. Use a low gear and brief, moderate brake applications.

Study tips for the Arizona General Knowledge exam

The General Knowledge portion of the Arizona CDL exam is graded out of the bank of questions the Arizona Department of Transportation MVD draws from each year. While the exact bank is not published, every question is sourced from the General Knowledge chapter of the Arizona CDL handbook, which itself is derived from the FMCSA Model Commercial Driver's License Manual. That means studying our practice tests, reading the corresponding handbook chapter, and re-reading the parts you got wrong is genuinely the most efficient route to a first-time pass.

Most successful applicants follow a simple cycle: take the practice test cold, write down every question you missed, open the matching chapter of the official Arizona handbook, re-read the section that contains the right answer, then re-take the practice test 24 to 48 hours later. The 24-hour delay matters — sleep is when your brain commits new information to long-term memory, and CDL knowledge questions reward that kind of consolidated learning rather than cramming.

Pay particular attention to questions that include qualifier words like always, never, only, primary, or most. CDL test writers love to flip the right answer with a single qualifier. When two answer choices look almost identical, pay attention to the verb (is it must, should, or may?) and to any numbers (14 days, 100 air miles, 8 hours, 70/8 split). On endorsement tests in particular, watch for trick framing where a true statement about a different endorsement is offered as the "correct" answer to a question that is actually about General Knowledge.

Test-day logistics matter too. Bring photo ID, your Social Security card or birth certificate, your medical examiner's certificate (DOT card), and proof of state residency if you haven't already submitted those documents. The Arizona Department of Transportation MVD will not let you sit for the knowledge exam without your documentation, and most offices charge an additional fee for re-attempts. Arrive early — the wait at most CDL testing offices runs 30 to 60 minutes — and silence your phone before the exam begins.

Finally, keep your General Knowledge fundamentals sharp even when you're focused on the General Knowledge exam. Many states administer multiple knowledge tests in a single sitting, and questions on weight definitions (GVWR, GCWR, GAWR), stopping distance, and the pre-trip inspection routine show up across endorsements. If you're unsure on the basics, sit a fresh Arizona General Knowledge practice test before scheduling the real exam.

Next steps

Missed more than four questions? Re-read the General Knowledge study guide and the matching chapter in the official Arizona CDL handbook. Then come back and re-take the test. Once you can score 22 of 25 or higher on three runs in a row, you're in good shape to schedule the real exam at your local Arizona Department of Transportation MVD office.

Already comfortable with this endorsement? Drill another: AZ Air Brakes · AZ Combination Vehicles · AZ Hazardous Materials · AZ Passenger · AZ School Bus · AZ Tank Vehicle · AZ Doubles / Triples

New to the CDL process in Arizona? Read How to apply for a CDL in Arizona for the document checklist and step-by-step timeline.