Why should you take the starter key with you during the pre-trip inspection?

So no one can drive the vehicle while you are inspecting under it.

You will need it during the inspection.

The Class B and Class C vehicle inspection tests include an inspection of

the special features of the vehicle.

When inspecting the brakes, you should pay particular attention to

the brake linings or brake pads.

You are checking your steering and exhaust system during a pre-trip inspection. Which of these problems, if found, should be fixed before the vehicle is driven?

A small leak of power steering fluid

Steering wheel play of more than 10 degrees

When you check the alternator,

make sure it is securely mounted.

make sure that some of the wires are undamaged.

make sure that belt deflection is at least one inch.

make sure that some of the wires are securely fastened.

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20 questions
Pass mark 80%

Alaska CDL: Pre-Trip Inspection Practice Test

20 pre-trip inspection questions for the Alaska CDL Knowledge Test, out of 91 in the app. Answer each to see whether you got it right and why. The real Alaska Pre-Trip Inspection test has 20 questions and you need 16 correct (80%) to pass.

Facts updated Oct 26, 2026
Official source: law.cornell.edu
Independent, not affiliated with the DMV. How we write our questions

How it works

1Pick an answer20 questions, one tap each.
2See the ruleRight or wrong, every answer is explained.
3Get your scoreCompared with the real 80% pass mark.

Start the test

0/20 answered0 correctPass mark 80%

1Question 1 of 20
What do you use the dipstick to check?
Not quite. The answer is Oil level
Use the dipstick to check the oil level in the engine. If the oil level is below the refill mark, add oil before you start to drive.
2Question 2 of 20
Why should you take the starter key with you during the pre-trip inspection?
Not quite. The answer is So no one can drive the vehicle while you are inspecting under it.
Take the starter key with you during the inspection so no one can drive your vehicle while you are inspecting under it.
3Question 3 of 20
On a school bus, which of the following must be mounted securely on the frame of the vehicle, with no loose or damaged fittings?
Not quite. The answer is Stop arm
The stop arm is an extensible stop sign on the side of the school bus. A control lets you swing out the stop arm to warn other drivers that you're stopping to pick up or let off passengers. During your inspection, check that the stop arm is undamaged and mounted securely on the vehicle frame, and there are no loose fittings. Activate the stop arm to be sure that it extends fully.
4Question 4 of 20
The Class B and Class C vehicle inspection tests include an inspection of
Not quite. The answer is the special features of the vehicle.
Class B and Class C CDLs cover the operation of a wide variety of different types of vehicles with their own special features. You must perform the vehicle inspection test in a vehicle that is representative of the kinds of vehicles that you plan to drive professionally. As part of the test, you will have to inspect any special features of your vehicle (such as the special features of school buses if you're using one for the test).
5Question 5 of 20
You are checking for damage to the longitudinal members, cross members, box, or floor. What are you inspecting?
Not quite. The answer is Frame
The frame consists of the structural members for supporting the body of the vehicle or trailer. When inspecting the frame, (1) check for cracks; (2) check for broken welds; and (3) check for illegal holes or other damage to the longitudinal frame members, cross members, box, or floor.
6Question 6 of 20
Which of these converts air pressure to mechanical force to operate the brake at a wheel?
Not quite. The answer is Brake chamber
The brake chamber (one at each wheel) converts air pressure to mechanical force to operate the brake at that wheel. When you press the brake pedal, compressed air from a service tank enters the brake chamber. Air pressure pushes out the brake chamber's pushrod, which moves the slack adjuster. The moving slack adjuster applies the brake.
7Question 7 of 20
When inspecting the brakes, you should pay particular attention to
Not quite. The answer is both of the above.
When inspecting the brakes, check that the drums (or discs) do not have cracks longer than one-half the width of the friction area. Also check that the linings (or pads) are neither loose nor soaked with oil or grease. The linings (or pads) must not be worn dangerously thin either.
8Question 8 of 20
During the pre-trip inspection, which of the following does NOT get checked at the rear of a trailer?
Not quite. The answer is Landing gear
You check the landing gear when you inspect the side of the trailer.
9Question 9 of 20
Which of the following can disengage the engine from the drivetrain?
Not quite. The answer is Clutch and gearshift
To ensure that your vehicle doesn't move once you start the engine, first depress the clutch (unless the vehicle has an automatic transmission) and put the gearshift in neutral (or Park for an automatic transmission). Once the engine has started, slowly release the clutch.
10Question 10 of 20
You are checking your steering and exhaust system during a pre-trip inspection. Which of these problems, if found, should be fixed before the vehicle is driven?
Not quite. The answer is Both of the above
Your steering system is critical to your safety, especially in an emergency. Excessive steering wheel play may make it difficult for you to know which way your front wheels are pointed. A leak of power steering fluid may eventually lead to power steering failure if left uncorrected.
11Question 11 of 20
What should be fully engaged with no loose or missing pins in the slide mechanism of the sliding fifth wheel?
Not quite. The answer is Locking pins
On many vehicles, the fifth wheel is designed to slide forward and backward on slider rails. If that is so on your vehicle, check the sliding fifth wheel locking pins. Make sure that none of them are loose or missing and that all of them are fully engaged.
12Question 12 of 20
What should not be bent, damaged, or rusted through and should be evenly centered with the dual wheels and tires evenly separated?
Not quite. The answer is Spacers
Wheel spacers adjust wheel offset. During your pre-trip inspection, inspect each wheel that has wheel spacers to make sure that no spacers are missing, bent, damaged, or rusted through. Make sure that dual tires aren't touching. Dual tires that touch can catch fire.
13Question 13 of 20
What heats the cab and prevents frost from forming on the windshield?
Not quite. The answer is Heater/defroster
The heater/defroster provides a stream of warmed air. By selecting the appropriate vents, you can choose whether the air will heat the cab or melt frost on the windshield.
14Question 14 of 20
When you inspect your vehicle's doors, check that the hinges are secure and the _______ are in good condition.
Not quite. The answer is seals
Damaged door seals allow drafts or rain to get inside. Check if the door seals are intact and undamaged. Replace any leaky door seals.
15Question 15 of 20
When you check the alternator,
Not quite. The answer is make sure it is securely mounted.
When checking the alternator, check that it is securely fastened. Check that all wires are undamaged and securely fastened. Check that the belt is in good condition and the belt deflection is between 1/2 inch and 3/4 inch.
16Question 16 of 20
Which of these must be securely mounted to prevent road materials from being thrown by your vehicle's tires?
Not quite. The answer is Splash guards
Splash guards (mud flaps) behind the tires prevent debris from hitting other vehicles. During your pre-trip inspection, check that splash guards are present, undamaged, securely mounted, and not dragging on the ground or rubbing on the tires.
17Question 17 of 20
What releases the fifth wheel locking jaws so the trailer can be coupled?
Not quite. The answer is Release arm
The release arm allows you to disengage the fifth-wheel locking jaws so you can uncouple the trailer. During your pre-trip inspection, check that the release arm is in the engaged position and the safety latch (if so equipped) is in place.
18Question 18 of 20
If the wheel has a sight glass, check that the oil level is adequate. Otherwise, look for leaks around the
Not quite. The answer is hub oil seals and axle seals.
As part of your pre-trip inspection of the wheels, check the axle seals and the hub oil/grease seals for leaks. Look for oil or grease on the wheels and any visible evidence of cracks or leaks. If the wheel has a sight glass, you can visually confirm that the oil level is adequate.
19Question 19 of 20
During your inspection, checking which of these will NOT help prevent a vehicle fire?
Not quite. The answer is Battery fluid level
There are many possible causes of vehicle fires, including poor cargo ventilation and electrical short circuits caused by damaged insulation or loose connections. A low battery fluid level can impair battery performance and even damage the battery, but it's unlikely to cause a fire.
20Question 20 of 20
If worn, what can cause excessive heat buildup from a reduced ability to absorb and dissipate heat, possibly leading to loss of brake response?
Not quite. The answer is Brake drum / linings
Brake linings use friction to turn the vehicle's kinetic energy into heat. However, excessive heat from overuse of the brakes may cause the brake linings to wear out faster, leading to brake fade or failure. Also, if one brake is out of adjustment and can't do its job, the other brakes will have to work harder, causing them to overheat.

Questions people ask

Is this Alaska CDL: Pre-Trip Inspection Practice Test like the real Alaska CDL Knowledge Test?

The questions are written in the same style as the real test, from official sources, with an explanation for each answer. The real test has 20 questions; this free test has 20.

How many questions are on the Alaska CDL Knowledge Test?

The General Knowledge test has 20 questions. Each class and endorsement adds its own test.

What score do you need to pass the Alaska CDL Knowledge Test?

You need 16 out of 20 correct (80%).

How old do you have to be to take the Alaska CDL Knowledge Test?

You can take it from age 18.

Where can I practice more questions?

The Driving Exam Prep app has the full question bank for your test, a step-by-step roadmap, a mistakes review and a readiness score against the real pass mark.

Official sources

Our questions are written from these official sources. Always study your official handbook too: rules change, and our practice questions may differ from your real test.

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What do you use the dipstick to check?

Why should you take the starter key with you during the pre-trip inspection?

On a school bus, which of the following must be mounted securely on the frame of the vehicle, with no loose or damaged fittings?

The Class B and Class C vehicle inspection tests include an inspection of

You are checking for damage to the longitudinal members, cross members, box, or floor. What are you inspecting?

Which of these converts air pressure to mechanical force to operate the brake at a wheel?

When inspecting the brakes, you should pay particular attention to

During the pre-trip inspection, which of the following does NOT get checked at the rear of a trailer?

Which of the following can disengage the engine from the drivetrain?

You are checking your steering and exhaust system during a pre-trip inspection. Which of these problems, if found, should be fixed before the vehicle is driven?

What should be fully engaged with no loose or missing pins in the slide mechanism of the sliding fifth wheel?

What should not be bent, damaged, or rusted through and should be evenly centered with the dual wheels and tires evenly separated?

What heats the cab and prevents frost from forming on the windshield?

When you inspect your vehicle's doors, check that the hinges are secure and the _______ are in good condition.

When you check the alternator,

Which of these must be securely mounted to prevent road materials from being thrown by your vehicle's tires?

What releases the fifth wheel locking jaws so the trailer can be coupled?

If the wheel has a sight glass, check that the oil level is adequate. Otherwise, look for leaks around the

During your inspection, checking which of these will NOT help prevent a vehicle fire?

If worn, what can cause excessive heat buildup from a reduced ability to absorb and dissipate heat, possibly leading to loss of brake response?

More topic

Questions people ask

Official sources

Keep going

Your license is one lesson closer.