TheoryCDL Class a Practice Questions
Free CDL Class A practice questions with answers and plain-English explanations. Browse the PDF, video and online mock test.
CDL Class A Questions
Open each answer, read the explanation, then continue into the full practice flow.
Q1During a pre-trip inspection, which component should you check for cracks, missing bolts, and proper mounting?
Show answer
✓ Correct answer: Coupling device (fifth wheel)
The CDL manual requires you to inspect the fifth wheel for cracks, broken or missing parts, and to verify it is properly mounted and locked before every trip.
Q2What is the correct order to begin the 7-step pre-trip inspection?
Show answer
✓ Correct answer: Approach the vehicle, look for leaks and damage from a distance, then check the engine compartment
Step 1 of the 7-step inspection is to approach and do an overview of the vehicle from a distance, looking for obvious damage, leaks, or tilting before moving closer.
Q3During a pre-trip inspection of the engine compartment, which fluid level does the CDL manual specifically require you to check?
Show answer
✓ Correct answer: Engine oil level
The CDL manual requires checking engine oil level as part of the engine compartment inspection; it must be at the proper level with no signs of leaks.
Q4How many steps are in the standard CDL 7-step pre-trip inspection procedure?
Show answer
✓ Correct answer: 7
The standard FMCSA/AAMVA CDL manual defines exactly 7 steps for the pre-trip vehicle inspection, covering everything from vehicle overview to signal and brake checks.
Q5While driving, your low air pressure warning light and buzzer activate. According to the CDL manual, at approximately what air pressure does this warning typically trigger?
Show answer
✓ Correct answer: 60 psi
The CDL manual states the low air pressure warning device must activate before pressure drops below 60 psi, signaling the driver to stop safely and not continue driving.
Q6During an en-route inspection stop, you notice one of your drive axle tires has a tread depth measuring 2/32 of an inch. What action is required?
Show answer
✓ Correct answer: You may continue; the minimum for drive axles is 2/32 inch
Federal regulations require a minimum tread depth of 4/32 inch on front axle tires and all drive axle tires; 2/32 inch is only the minimum for other positions, so a drive axle at 2/32 is an out-of-service condition.
Q7Which of the following brake defects found during inspection would place a vehicle out of service?
Show answer
✓ Correct answer: A cracked brake drum
A cracked brake drum is a critical out-of-service defect per FMCSA regulations because it compromises braking performance and could lead to complete brake failure.
Q8During a pre-trip inspection of the coupling, you push forward on the trailer and the fifth wheel does not release. What does this indicate?
Show answer
✓ Correct answer: The coupling is properly locked and secure
Pushing forward on the trailer while the tractor is in low gear and not releasing confirms the fifth wheel is properly locked onto the kingpin, which is a required part of the coupling inspection.
Q9During your pre-trip walk-around, you find that one running light on the trailer is not working. What must you do before driving?
Show answer
✓ Correct answer: Note the defect and have it repaired before operating the vehicle
Any lighting defect that affects required safety equipment must be repaired before the vehicle is operated; noting defects does not satisfy the requirement if the equipment is needed for legal operation.
Q10During a pre-trip inspection of a vehicle with air brakes, you fan the brakes to reduce air pressure. At approximately what pressure should the spring (parking) brakes automatically activate?
Show answer
✓ Correct answer: 40 psi
The CDL manual states that spring brakes should automatically activate (pop out) when air pressure falls into the range of approximately 20 to 45 psi, with the generally tested threshold around 40 psi, ensuring the vehicle is held if air is lost.
Full CDL Class A bank + unlimited mocks
Try 30 questions free. Unlock the complete CDL Class A question bank, every explanation, and unlimited timed mock exams. Practice on any device.
Unlock CDL Class A →