CDL General knowledge Practice Test 6

Question 1Which is a clue that a parked vehicle may be about to move?

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C: Brake or backup lights, exhaust, or movement inside the vehicle. Signs that a parked vehicle may pull out include people moving inside it, brake or backup lights and exhaust. Wisconsin Commercial Driver's Manual (BDS356), based on the AAMVA 2025 CDL Manual: 2.8.3 Drivers who are hazards, page 63.

Question 2According to the manual, how much more likely are you to be fatally injured if you are not wearing a safety belt and are thrown from the vehicle?

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C: 4 times. Not wearing a safety belt makes a fatal injury 4 times more likely if you are thrown from the vehicle, so stay belted whenever you drive a CMV. Wisconsin Commercial Driver's Manual (BDS356), based on the AAMVA 2025 CDL Manual: 1.4 Other CDL rules, page 31.

Question 3Before checking the engine compartment, what should you make sure of?

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B: The parking brakes are on and/or the wheels are chocked. Step 2 starts by making sure the parking brakes are on and/or the wheels are chocked. Wisconsin Commercial Driver's Manual (BDS356), based on the AAMVA 2025 CDL Manual: 2.1.5 Seven-step inspection method, page 36.

Question 4In stab braking, after you release the brakes because the wheels locked, when do you reapply them?

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D: As soon as the wheels start rolling. Reapply fully as soon as the wheels start rolling. It can take up to one second, and reapplying before they roll won't let the vehicle straighten out. Wisconsin Commercial Driver's Manual (BDS356), based on the AAMVA 2025 CDL Manual: 2.17.2 How to stop quickly and safely, page 85.

Question 5What does the slow-moving vehicle symbol look like?

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A: A red triangle with an orange center. The slow-moving vehicle symbol is a red triangle with an orange center. Wisconsin Commercial Driver's Manual (BDS356), based on the AAMVA 2025 CDL Manual: 2.8.3 Drivers who are hazards, page 64.

Question 6Under the federal rule, which counts as using a hand-held mobile phone while driving a CMV?

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D: Reaching for a phone so that you move out of your seated, belted driving position. Hand-held use includes holding a phone for a call, dialing with more than a single button, or moving out of your seated, belted position to reach for a phone. Wisconsin Commercial Driver's Manual (BDS356), based on the AAMVA 2025 CDL Manual: 2.9.4 Cell/mobile phones, page 67.

Question 7After starting the engine, how quickly should the oil pressure come up to normal?

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A: Within seconds. Normal oil pressure should show within a few seconds of starting the engine. Wisconsin Commercial Driver's Manual (BDS356), based on the AAMVA 2025 CDL Manual: 2.1.5 Seven-step inspection method, page 36.

Question 8Why shouldn't you jam on the brakes in an emergency?

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C: It keeps the wheels locked and causes a skid you can't control. Pushing the pedal as hard as you can only keeps the wheels locked up and causes a skid, and you can't control a skidding vehicle. Wisconsin Commercial Driver's Manual (BDS356), based on the AAMVA 2025 CDL Manual: 2.17.2 How to stop quickly and safely, page 86.

Question 9Which of these is a clue that a driver may be a confused tourist?

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D: Car-top luggage and out-of-state plates. Roof-top luggage and out-of-state plates point to tourists, who may stop or turn without warning. Wisconsin Commercial Driver's Manual (BDS356), based on the AAMVA 2025 CDL Manual: 2.8.3 Drivers who are hazards, page 64.

Question 10How long is a CDL disqualified for a second conviction for hand-held phone use in a CMV within 3 years?

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B: 60 days. A second hand-held phone conviction within 3 years brings a 60-day disqualification; a third or later one within 3 years brings 120 days. Wisconsin Commercial Driver's Manual (BDS356), based on the AAMVA 2025 CDL Manual: 2.9.4 Cell/mobile phones, page 67.

Question 11In a vehicle with air brakes, air pressure should build from 50 to 90 psi within about:

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B: 3 minutes. On an air-brake vehicle, pressure should climb from 50 to 90 psi in 3 minutes or less. Wisconsin Commercial Driver's Manual (BDS356), based on the AAMVA 2025 CDL Manual: 2.1.5 Seven-step inspection method, page 36.

Question 12What are the two main reasons hydraulic brakes fail?

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B: Loss of hydraulic pressure and brake fade on long downgrades. Most hydraulic brake failures come from loss of hydraulic pressure or brake fade on long downgrades. Wisconsin Commercial Driver's Manual (BDS356), based on the AAMVA 2025 CDL Manual: 2.17.3 Brake failure, page 86.

Question 13Which of these is a clue that a driver may be impaired?

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C: An open window in cold weather. Clues to impaired drivers include weaving, leaving the road, stopping at the wrong time, sudden speed changes and an open window in cold weather. Wisconsin Commercial Driver's Manual (BDS356), based on the AAMVA 2025 CDL Manual: 2.8.3 Drivers who are hazards, page 65.

Question 14How long is a CDL disqualified for a third texting-while-driving conviction in a CMV within 3 years?

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C: 120 days. For three or more texting convictions within 3 years, the disqualification is 120 days. Wisconsin Commercial Driver's Manual (BDS356), based on the AAMVA 2025 CDL Manual: 2.9.5 Texting, page 68.

Question 15At what pressure does the air compressor governor usually cut out?

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C: Around 120–140 psi. Governor cut-out is usually around 120–140 psi, but check the figure for your own vehicle. Wisconsin Commercial Driver's Manual (BDS356), based on the AAMVA 2025 CDL Manual: 2.1.5 Seven-step inspection method, page 36.

Question 16Your hydraulic brake pedal goes to the floor. Which action can help?

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A: Downshift, pump the brakes, use the parking brake, and look for an escape route. Downshift, pump the brakes, use the parking brake (which is separate from the hydraulic system) and find an escape route. Wisconsin Commercial Driver's Manual (BDS356), based on the AAMVA 2025 CDL Manual: 2.17.3 Brake failure, page 86.

Question 17A driver ahead makes an over-the-shoulder check. What might they be about to do?

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B: Change lanes. A driver glancing over the shoulder may be about to change lanes. These body-movement clues are easiest to spot in motorcyclists and bicyclists. Wisconsin Commercial Driver's Manual (BDS356), based on the AAMVA 2025 CDL Manual: 2.8.3 Drivers who are hazards, page 65.

Question 18When may a CMV driver use a hand-held phone or text while driving?

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A: When necessary to communicate with law enforcement or other emergency services. There is an emergency exception allowing hand-held use or texting when necessary to communicate with law enforcement or emergency services. Wisconsin Commercial Driver's Manual (BDS356), based on the AAMVA 2025 CDL Manual: 2.9.4 Cell/mobile phones, page 67.

Question 19On a trailer, the yellow ABS light on the left rear stays on after start-up. What does this mean?

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B: The trailer ABS is not working properly. For trailers, if the yellow light on the left rear stays on, the ABS is not working properly. Wisconsin Commercial Driver's Manual (BDS356), based on the AAMVA 2025 CDL Manual: 2.1.5 Seven-step inspection method, page 36.

Question 20Your brakes fail on a downgrade and there is an escape ramp ahead. What should you do?

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D: Use the escape ramp. Use the escape ramp whenever you lose your brakes on a downgrade; skipping it makes a serious crash much more likely. Wisconsin Commercial Driver's Manual (BDS356), based on the AAMVA 2025 CDL Manual: 2.17.3 Brake failure, page 86.

Question 21What does it mean to be "in conflict" with another road user?

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A: You need to change speed and/or direction to avoid hitting someone. You are in conflict when you must change speed or direction to avoid hitting someone, such as at intersections, merges and lane drops. Wisconsin Commercial Driver's Manual (BDS356), based on the AAMVA 2025 CDL Manual: 2.8.3 Drivers who are hazards, page 65.

Question 22Which hazard class is explosives such as dynamite, fireworks and ammunition?

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A: Class 1. Class 1 is explosives, such as dynamite, fireworks and ammunition. Wisconsin Commercial Driver's Manual (BDS356), based on the AAMVA 2025 CDL Manual: 2.23.1 What are hazardous materials?, page 95.

Question 23After the engine starts, how should the coolant temperature gauge behave?

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D: Begin a gradual rise to the normal operating range. Coolant temperature should begin a gradual rise to the normal operating range. Wisconsin Commercial Driver's Manual (BDS356), based on the AAMVA 2025 CDL Manual: 2.1.5 Seven-step inspection method, page 37.

Question 24Your hydraulic brakes fail and there is no escape ramp. When should you take an escape route such as an open field or side road?

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C: As soon as you know your brakes are not working. Make the move as soon as you know your brakes aren't working; the longer you wait, the faster you'll go and the harder it is to stop. Wisconsin Commercial Driver's Manual (BDS356), based on the AAMVA 2025 CDL Manual: 2.17.3 Brake failure, page 86.

Question 25When you see a hazard, what should you do in your mind?

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D: Think about the emergencies that could develop and plan what you would do. Always have a plan: think about the emergencies a hazard could create and figure out what you would do. Wisconsin Commercial Driver's Manual (BDS356), based on the AAMVA 2025 CDL Manual: 2.8.4 Always have a plan, page 65.

Question 1Which is a clue that a parked vehicle may be about to move?

Question 2According to the manual, how much more likely are you to be fatally injured if you are not wearing a safety belt and are thrown from the vehicle?

Question 3Before checking the engine compartment, what should you make sure of?

Question 4In stab braking, after you release the brakes because the wheels locked, when do you reapply them?

Question 5What does the slow-moving vehicle symbol look like?

Question 6Under the federal rule, which counts as using a hand-held mobile phone while driving a CMV?

Question 7After starting the engine, how quickly should the oil pressure come up to normal?

Question 8Why shouldn't you jam on the brakes in an emergency?

Question 9Which of these is a clue that a driver may be a confused tourist?

Question 10How long is a CDL disqualified for a second conviction for hand-held phone use in a CMV within 3 years?

Question 11In a vehicle with air brakes, air pressure should build from 50 to 90 psi within about:

Question 12What are the two main reasons hydraulic brakes fail?

Question 13Which of these is a clue that a driver may be impaired?

Question 14How long is a CDL disqualified for a third texting-while-driving conviction in a CMV within 3 years?

Question 15At what pressure does the air compressor governor usually cut out?

Question 16Your hydraulic brake pedal goes to the floor. Which action can help?

Question 17A driver ahead makes an over-the-shoulder check. What might they be about to do?

Question 18When may a CMV driver use a hand-held phone or text while driving?

Question 19On a trailer, the yellow ABS light on the left rear stays on after start-up. What does this mean?

Question 20Your brakes fail on a downgrade and there is an escape ramp ahead. What should you do?

Question 21What does it mean to be "in conflict" with another road user?

Question 22Which hazard class is explosives such as dynamite, fireworks and ammunition?

Question 23After the engine starts, how should the coolant temperature gauge behave?

Question 24Your hydraulic brakes fail and there is no escape ramp. When should you take an escape route such as an open field or side road?

Question 25When you see a hazard, what should you do in your mind?

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