CDL General Knowledge Practice Test 2026：第5套练习测试

1. 第1题，共25题

   What are escape ramps for?

   • AParking overnight
   • BChecking brakes on flat ground
   • CLetting slow trucks pass
   • DStopping runaway vehicles safely
   显示答案

   答案: D. Stopping runaway vehicles safely

   Escape ramps are built to stop vehicles whose brakes have failed. Know where they are on your route.

2. 第2题，共25题

   What is the following distance rule for heavy vehicles?

   • A1 second per 10 feet of length, plus 1 second over 40 mph
   • B1 second per 20 feet of length at any speed
   • C2 seconds for any vehicle at any speed
   • D1 car length for each 10 mph of speed
   显示答案

   答案: A. 1 second per 10 feet of length, plus 1 second over 40 mph

   Leave 1 second for every 10 feet of length below 40 mph, and add 1 second above 40 mph.

3. 第3题，共25题

   Your truck is 40 feet long and you are driving at 35 mph. What following distance should you keep?

   • AAt least 2 seconds
   • BAt least 4 seconds
   • CAt least 8 seconds
   • DAt least 5 seconds
   显示答案

   答案: B. At least 4 seconds

   40 feet means 4 seconds. Because you are below 40 mph, you do not add the extra second.

4. 第4题，共25题

   Your rig is 60 feet long and you are driving at 55 mph. What following distance should you keep?

   • AAt least 4 seconds
   • BAt least 7 seconds
   • CAt least 3 seconds
   • DAt least 6 seconds
   显示答案

   答案: B. At least 7 seconds

   60 feet means 6 seconds, plus 1 more second because you are above 40 mph.

5. 第5题，共25题

   Someone is tailgating you. What should you do?

   • ALeave more space ahead and avoid quick changes
   • BSpeed up to get away from them
   • CSlow down suddenly to make them back off
   • DFlash your brake lights to warn them
   显示答案

   答案: A. Leave more space ahead and avoid quick changes

   Give yourself more space ahead so you will not have to stop suddenly. Do not speed up or play tricks with your lights.

6. 第6题，共25题

   Which vehicle is more likely to hit a low bridge or overhang?

   • AAn empty van
   • BThey are always the same height
   • CA loaded van
   • DA loaded flatbed with a low load
   显示答案

   答案: A. An empty van

   An empty van rides higher than a loaded one. Also, do not assume posted heights are correct.

7. 第7题，共25题

   The diagram shows a tractor-trailer making a tight right turn. What is the right way to make the turn?

   • ATurn sharply from the left lane
   • BLet the trailer roll over the curb
   • CKeep the rear by the curb; swing wide as you finish
   • DSwing wide to the left before you start the turn
   显示答案

   答案: C. Keep the rear by the curb; swing wide as you finish

   Turn slowly, keep the rear close to the curb, and use the lane you are entering as you complete the turn.

8. 第8题，共25题

   Why should you not swing left before making a right turn in a large vehicle?

   • AA car may try to pass you on the right
   • BIt wears out your steering tires quickly
   • CIt is always illegal in every state
   • DIt makes the trailer jackknife in the turn
   显示答案

   答案: A. A car may try to pass you on the right

   If you swing left first, a car may slip in on your right. Swing wide as you complete the turn instead.

9. 第9题，共25题

   When turning left in a large vehicle, when should you start the turn?

   • AAt the center of the intersection
   • BFrom the right-hand lane
   • CBefore you reach the intersection
   • DAs soon as you see a gap
   显示答案

   答案: A. At the center of the intersection

   Go to the center of the intersection before you turn left, so your rear wheels do not cut the corner.

10. 第10题，共25题

    There are two left-turn lanes. Which one should a large vehicle use?

    • ANeither; go straight instead
    • BEither one
    • CThe left-hand turn lane
    • DThe right-hand turn lane
    显示答案

    答案: D. The right-hand turn lane

    Use the right-hand lane of two left-turn lanes. You may need to swing right to clear the turn.

11. 第11题，共25题

    Distraction makes you react half a second slower. What does this do to crash risk?

    • AIt doubles it
    • BIt has no real effect
    • CIt lowers it
    • DIt raises it a little
    显示答案

    答案: A. It doubles it

    Reacting just half a second slower because of a distraction doubles the chance of a crash.

12. 第12题，共25题

    What is the safest way to make or take a phone call?

    • APull off the road safely first
    • BText instead of calling
    • CHold the phone low and keep driving
    • DCall only on straight roads
    显示答案

    答案: A. Pull off the road safely first

    Pull over to a safe spot before using your phone. Even hands-free calls distract you.

13. 第13题，共25题

    An aggressive driver confronts you. What should you do?

    • ASpeed up to stay ahead of them
    • BGet out of the way; avoid eye contact
    • CBrake suddenly in front of them
    • DGesture back so they know you saw
    显示答案

    答案: B. Get out of the way; avoid eye contact

    Make every effort to get out of their way, do not make eye contact, and report them if you can safely.

14. 第14题，共25题

    About how far ahead can you see with low beam headlights?

    • AAbout 50 feet
    • BAbout 500 feet
    • CAbout 250 feet
    • DAbout 1,000 feet
    显示答案

    答案: C. About 250 feet

    Low beams show about 250 feet ahead. High beams show about 350 to 500 feet.

15. 第15题，共25题

    When should you dim your high beams?

    • AOnly when the other driver flashes you
    • BOnly when you are driving in a town
    • CWithin 500 feet of an oncoming or leading vehicle
    • DWithin 100 feet of any other vehicle
    显示答案

    答案: C. Within 500 feet of an oncoming or leading vehicle

    Dim your lights within 500 feet of an oncoming vehicle and when following another vehicle.

16. 第16题，共25题

    You feel very sleepy while driving at night. What is the only safe cure?

    • ATurn the radio up loud
    • BOpen the window for air
    • CGet off the road and sleep
    • DDrink a strong coffee
    显示答案

    答案: C. Get off the road and sleep

    Sleep is the only safe cure for being sleepy. Stop driving.

17. 第17题，共25题

    What is the best advice for driving in heavy fog?

    • AUse high beams so you can see farther
    • BFollow the tail lights ahead closely
    • CSpeed up to get through it quickly
    • DDon't drive; wait at a rest area until it clears
    显示答案

    答案: D. Don't drive; wait at a rest area until it clears

    If you can, don't drive in fog. If you must, slow down before entering it and use low beams and fog lights.

18. 第18题，共25题

    What should you know about tire chains before winter driving?

    • AOne chain is enough for any truck
    • BLearn to put them on when the storm starts
    • CCarry enough, plus extra cross-links, and practice
    • DChains are only needed on dry roads
    显示答案

    答案: C. Carry enough, plus extra cross-links, and practice

    Carry enough chains and extra cross-links, check them for broken hooks and worn links, and learn to put them on before you need them.

19. 第19题，共25题

    Why is an exhaust leak dangerous in winter?

    • AIt makes the heater run too hot
    • BCarbon monoxide can enter the cab
    • CIt lowers the pressure in the tires
    • DIt freezes the fuel in the lines
    显示答案

    答案: B. Carbon monoxide can enter the cab

    Exhaust leaks can let carbon monoxide into the cab. This gas causes sleepiness and can kill.

20. 第20题，共25题

    Your brakes got wet in heavy rain. How can you dry them?

    • AStop and wait an hour for them to air dry
    • BPump the brakes quickly while parked
    • CBrake lightly while driving slowly in a low gear
    • DBrake hard several times at highway speed
    显示答案

    答案: C. Brake lightly while driving slowly in a low gear

    Slow down, use a low gear and gently apply the brakes to heat and dry them.

21. 第21题，共25题

    In very hot weather, how often should you check your tires?

    • AOnly at the start of the trip
    • BEvery 500 miles
    • CEvery 2 hours or every 100 miles
    • DOnce a day
    显示答案

    答案: C. Every 2 hours or every 100 miles

    Heat raises tire pressure and temperature. Inspect tires every 2 hours or every 100 miles in hot weather.

22. 第22题，共25题

    A tire is too hot to touch. What should you do?

    • ASpray it with cold water and drive on
    • BLet some air out
    • CStay stopped until it cools off
    • DKeep driving to cool it with air
    显示答案

    答案: C. Stay stopped until it cools off

    Wait until a hot tire cools. Do not let air out, because the pressure will be too low when the tire cools.

23. 第23题，共25题

    About how long does a typical tractor-trailer need to clear a single railroad track?

    • AAt least 14 seconds
    • BAbout 7 seconds
    • CMore than 1 minute
    • DAbout 3 seconds
    显示答案

    答案: A. At least 14 seconds

    A typical tractor-trailer needs at least 14 seconds to clear a single track and more than 15 seconds for a double track.

24. 第24题，共25题

    What must you never do while driving across railroad tracks?

    • ADrive in a low gear
    • BKeep moving
    • CShift gears
    • DLook both ways
    显示答案

    答案: C. Shift gears

    Never change gears while crossing the tracks. You could stall on them.

25. 第25题，共25题

    Which vehicles must stop 15 to 50 feet before a railroad crossing?

    • ABuses with passengers and some hazmat vehicles
    • BOnly school buses carrying students
    • COnly vehicles over 80,000 pounds
    • DOnly vehicles that have air brakes
    显示答案

    答案: A. Buses with passengers and some hazmat vehicles

    Federal rules require buses with passengers and vehicles carrying certain hazardous materials to stop 15 to 50 feet from the tracks.

键盘：按1–4作答，按 Enter 进入下一题。

真实考试：Varies by state; usually 50 questions, with 40 correct needed (80%)