CDL General Knowledge Practice Test 2026：第3套练习测试

CDL General Knowledge Practice Test 练习测试第3套（共6套）：再练25道题，附答案和解释。

商用车辆
美国
150道题
核对于2026年10月10日

第1题，共25题
Is a radar detector allowed in a commercial motor vehicle?
- Yes, if it is turned off
- Yes, on interstate highways
- Only in states that allow them
- No
显示答案
答案: D. No
A driver may not use a radar detector in a CMV or drive a CMV that has one in it.
第2题，共25题
In the seven-step inspection method, what is the first step?
- Vehicle overview
- Check the signal lights
- Check the brakes
- Check the engine compartment
显示答案
答案: A. Vehicle overview
Step 1 is the vehicle overview: general condition, leaning, leaks, hazards nearby and the last inspection report.
第3题，共25题
Before you check the engine compartment, what should you do?
- Turn on the high beams and flashers
- Start the engine and let it warm up
- Set the parking brake or chock the wheels
- Release the parking brake fully
显示答案
答案: C. Set the parking brake or chock the wheels
Step 2 starts by making sure the vehicle cannot move: set the parking brake and/or chock the wheels.
第4题，共25题
In which step of the seven-step inspection do you check tires, wheels, suspension and brakes on each side of the vehicle?
- Step 6, the signal lights
- Step 1, the overview
- Step 3, inside the cab
- Step 5, the walkaround
显示答案
答案: D. Step 5, the walkaround
The walkaround in step 5 covers lights, tires, wheels, suspension, brakes, cargo securement and fuel tanks on every side.
第5题，共25题
What is the last step of the seven-step inspection?
- Read the last inspection report
- Check the engine oil
- Walk around the vehicle
- Start the engine and check the brakes
显示答案
答案: D. Start the engine and check the brakes
Step 7 is to start the engine and check the brake system, including the parking brake and service brake tests.
第6题，共25题
What is the minimum tread depth for the front (steering) tires?
- 4/32 inch in every major groove
- 1/32 inch in every major groove
- 6/32 inch in every major groove
- 2/32 inch in every major groove
显示答案
答案: A. 4/32 inch in every major groove
Front tires need at least 4/32 inch of tread in every major groove.
第7题，共25题
What is the minimum tread depth for tires that are not on the front axle?
- 4/32 inch
- 6/32 inch
- 2/32 inch
- 1/32 inch
显示答案
答案: C. 2/32 inch
Tires other than the front tires need at least 2/32 inch of tread in every major groove.
第8题，共25题
How much play in the steering wheel can make the vehicle hard to steer?
- More than 45 degrees (about 8 inches on the rim)
- Any play at all, even less than a quarter inch
- More than 2 degrees (about half an inch on the rim)
- More than 10 degrees (about 2 inches on a 20-inch wheel)
显示答案
答案: D. More than 10 degrees (about 2 inches on a 20-inch wheel)
Steering wheel play of more than 10 degrees can make it hard to steer.
第9题，共25题
How do you check hydraulic brakes during the inspection?
- Drive at 30 mph and brake hard; the truck should stop straight
- Pump three times, then hold for five seconds; the pedal should not move
- Hold the pedal for one minute with the engine off; it should sink
- Press the pedal once quickly; it should spring back up right away
显示答案
答案: B. Pump three times, then hold for five seconds; the pedal should not move
With hydraulic brakes, pump three times and hold for five seconds. The pedal should stay firm.
第10题，共25题
How do you test the service brakes at the end of the inspection?
- Move forward at about 5 mph and brake firmly
- Apply the parking brake while moving
- Pump the pedal several times while parked
- Drive at highway speed and brake hard
显示答案
答案: A. Move forward at about 5 mph and brake firmly
Go forward slowly, about 5 mph, then brake firmly. Note any pulling or delay.
第11题，共25题
How do you check that the parking brake will hold?
- Push against the truck by hand from behind
- Set it and gently pull against it in a low gear
- Release it at highway speed and feel the pull
- Park on a steep hill and walk away to see
显示答案
答案: B. Set it and gently pull against it in a low gear
With the parking brake on, try to pull forward gently in a low gear. The vehicle should not move.
第12题，共25题
Which emergency equipment must a truck carry?
- A spare tire, a tow strap and jumper cables
- A fire extinguisher, warning devices and spare fuses
- Snow chains, a jack and a tire iron
- A first aid kit, a shovel and a flashlight
显示答案
答案: B. A fire extinguisher, warning devices and spare fuses
Required emergency equipment is a charged, rated fire extinguisher, warning devices such as three reflective triangles, and spare fuses unless the vehicle has circuit breakers.
第13题，共25题
Your oil pressure gauge shows low or falling pressure while you drive. What should you do?
- Speed up to raise the pressure
- Turn off the gauge
- Keep driving and check it at your next stop
- Stop as soon as it is safe
显示答案
答案: D. Stop as soon as it is safe
Low or changing oil pressure can mean engine damage. Stop right away when it is safe.
第14题，共25题
You find defects listed on the previous driver's inspection report. When should you sign the report?
- Only if the defects were repaired or certified as not needing repair
- Only at the end of your own trip, after you drive the vehicle
- Always, before you start the engine, whatever the report says
- Never; only a mechanic may sign an inspection report
显示答案
答案: A. Only if the defects were repaired or certified as not needing repair
Review the last report and sign it only when the defects listed were certified as repaired or not needing repair.
第15题，共25题
When you must back up, which way should you back if you have a choice?
- Into traffic
- Uphill
- Toward the driver's side
- Toward the right side
显示答案
答案: C. Toward the driver's side
Backing toward the driver's side lets you see better.
第16题，共25题
What does G.O.A.L. mean when backing?
- Get Out And Look
- Gear Options Are Limited
- Go Only At Low speed
- Give Others A Lane
显示答案
答案: A. Get Out And Look
Before and while backing, get out and look at your path if you are not sure what is behind you.
第17题，共25题
How should you back a large vehicle?
- Quickly, to finish the move
- In the highest reverse gear
- Slowly, in the lowest reverse gear
- In neutral, letting it roll
显示答案
答案: C. Slowly, in the lowest reverse gear
Back slowly in the lowest reverse gear so you can correct steering errors and stop quickly.
第18题，共25题
You are backing a trailer and want the trailer to go to the left. Which way do you turn the steering wheel?
- Hold it straight
- Turn it left, then quickly right
- To the left
- To the right
显示答案
答案: D. To the right
When backing a trailer, turn the steering wheel in the opposite direction from where you want the trailer to go.
第19题，共25题
Which kind of manual transmission usually needs double clutching?
- An unsynchronized transmission
- An automatic transmission
- A synchronized transmission
- Any transmission in top gear
显示答案
答案: A. An unsynchronized transmission
Unsynchronized manual transmissions usually need double clutching. Synchronized ones do not.
第20题，共25题
When should you downshift?
- After speed builds on a downgrade
- In the middle of a curve
- Before a downgrade and before a curve
- Only when the engine stalls
显示答案
答案: C. Before a downgrade and before a curve
Shift down before a downgrade and before a curve so you stay in control.
第21题，共25题
What should you do with a retarder on wet, icy or snowy roads?
- Set it to the highest level
- Use it instead of the brakes
- Turn it off
- Use it only in curves
显示答案
答案: C. Turn it off
Retarders can make the drive wheels skid on slippery roads, so turn them off.
第22题，共25题
Your drive wheels start to spin as you pull away. What should you do?
- Apply the trailer brakes
- Take your foot off the accelerator
- Shift into a higher gear quickly
- Press harder on the accelerator
显示答案
答案: B. Take your foot off the accelerator
If the drive wheels spin, ease off the accelerator to regain traction.
第23题，共25题
How far ahead do most good drivers look?
- 30 to 40 seconds
- 12 to 15 seconds
- 3 to 5 seconds
- 1 to 2 seconds
显示答案
答案: B. 12 to 15 seconds
Looking 12 to 15 seconds ahead gives you time to spot hazards and plan.
第24题，共25题
At highway speed, looking 12 to 15 seconds ahead means looking about how far?
- About 2 miles
- About 100 feet
- About one city block
- About a quarter of a mile
显示答案
答案: D. About a quarter of a mile
At lower speeds 12 to 15 seconds is about one block. At highway speeds it is about a quarter of a mile.
第25题，共25题
How do convex (curved) mirrors make objects look?
- Smaller and farther away than they really are
- Closer but the right size
- Larger and closer than they really are
- Exactly as they are
显示答案
答案: A. Smaller and farther away than they really are
Convex mirrors show a wider area, but things look smaller and farther away.

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