Nevada DMV CDL General Knowledge Practice Test 3
Test 3 of 5. Pick an answer for each question to see if it is right and why; your score appears at the end. You need 40 correct answers to pass, the same ratio as the real Nevada test.
- Questions50
- Correct to pass40
- Passing score80%
- Minimum age18 years
-
1. On a tractor with a sliding fifth wheel, what does moving the fifth wheel forward do?
Show answer
Answer A: Puts more of the trailer weight onto the steering axle
Moving the coupling point forward transfers weight from the drive axles to the steering axle, which is how a driver corrects a drive axle that is over the limit.
-
2. Your load projects more than 4 feet beyond the rear of the vehicle. How must the projecting end be marked?
Show answer
Answer A: With a red or orange flag by day and a red lamp after dark
Federal rules require a warning flag on a rear projecting load in daylight and a red lamp on the end of it when lights are required.
-
3. What may a Nevada CDL holder aged 18 to 20 do?
Show answer
Answer D: Operate a commercial motor vehicle in intrastate commerce only, without carrying passengers for hire or placarded hazardous materials
Nevada grants CDLs to applicants aged 18 to 20 for intrastate commerce only, and that age group may not transport passengers for hire or placarded hazardous materials.
-
4. How should a commercial driver treat the speed posted for a curve?
Show answer
Answer B: As a limit set for cars in good conditions, so a heavy or tall load calls for a lower speed
Posted curve speeds are based on passenger vehicles in good conditions, and a tall or heavy load can roll over well below that speed.
-
5. During a trip you stop for a break. Which items should you check before driving on?
Show answer
Answer B: Tires, wheels and rims, brakes, lights, reflectors, electrical connections and cargo securement
Critical items can change during a trip, so each stop is used to recheck the tires, wheels, brakes, lights, connections and cargo.
-
6. When traction is poor, such as on packed snow, how should you speed up?
Show answer
Answer C: Very gradually, so the drive wheels do not spin
Gentle throttle keeps the drive wheels from breaking traction, because spinning wheels give up both grip and directional control.
-
7. What should the ammeter or voltmeter show once the engine is running?
Show answer
Answer D: A reading in the normal charging range
With the engine running, the alternator should be charging; a discharge reading or an abnormal charge level means an electrical fault.
-
8. What does the working load limit stamped on a chain or strap describe?
Show answer
Answer B: The maximum load the device is rated to hold in normal use
The working load limit is the rated safe capacity for everyday use, deliberately set well below the force that would break the device.
-
9. Why is a quick lane change particularly risky with a load of hanging meat or of livestock?
Show answer
Answer A: The load swings or leans and can keep pushing the trailer after you straighten out
A swinging or leaning load keeps moving after the vehicle has finished the maneuver, so its momentum acts on the trailer at the worst moment.
-
10. Loading heavy freight on top of lighter freight has what effect on the vehicle?
Show answer
Answer B: It raises the center of gravity and makes a rollover more likely
A high center of gravity lets the vehicle tip more easily in curves or during a sudden swerve.
-
11. Why should the mirrors be checked repeatedly while you make a tight turn?
Show answer
Answer C: To watch the rear of the vehicle clear other vehicles and objects
In a long vehicle the rear wheels cut inside the path of the front wheels, so only the mirrors show whether the rear is clearing curbs, poles and other vehicles.
-
12. What is the driver looking for when the exhaust system is inspected?
Show answer
Answer B: Loose, broken or missing pipes, brackets or clamps, and signs that exhaust is leaking
A loose or leaking exhaust system can send carbon monoxide into the cab and can put hot gas against parts that will burn.
-
13. For an unblocked article longer than 10 feet, the minimum is two tiedowns plus how many more?
Show answer
Answer B: One more for every additional 10 feet of length or any part of 10 feet
Past the first 10 feet, one more tiedown is added for each additional 10 feet of length or any fraction of that distance.
-
14. In dense city traffic you cannot see 12 seconds ahead because other vehicles block the view. What is the best response?
Show answer
Answer A: Slow down and open up more space in front of you
When you cannot see far enough ahead, extra following distance buys back the reaction time that the blocked view has taken away.
-
15. May a commercial driver use a hand-held phone while stopped at a red light?
Show answer
Answer B: No, a stop in traffic still counts as driving
Hand-held use is allowed only when the vehicle has been moved to the side of or off the highway and halted where it can safely remain stopped.
-
16. You want to check whether a tire on your truck is properly inflated. What is the correct method?
Show answer
Answer A: Measure the pressure with a tire gauge
Only a tire gauge tells you the actual pressure; a tire can look and sound normal while being badly underinflated.
-
17. You must leave the vehicle parked on a slight grade. What adds security beyond setting the parking brake?
Show answer
Answer D: Chocking the wheels so the vehicle cannot roll if the brake bleeds off
Chocks hold the vehicle mechanically and are the standard backup whenever a parked vehicle could roll.
-
18. Which parts of total stopping distance can a driver shorten simply by staying alert and looking far ahead?
Show answer
Answer B: Perception distance and reaction distance
Alertness shortens the time spent recognizing a hazard and moving your foot to the pedal; braking distance depends on speed, weight, brakes and the road surface.
-
19. Which clues warn you that a parked car may pull out or open a door?
Show answer
Answer A: Exhaust smoke, turned front wheels, a person in the seat
Signs of life in a parked vehicle, such as a running engine, turned wheels or an occupant, mean it may move or open a door into your path.
-
20. Cargo carried inside the cab must never do which of these?
Show answer
Answer C: Block the driver view, restrict arm or leg movement, or block an emergency exit
Anything inside the cab must leave the driver a clear view, free movement of the arms and legs, and an unobstructed way out of the vehicle.
-
21. Your drive wheels start to spin and the rear begins to slide while you accelerate on a slick surface. What should you do?
Show answer
Answer B: Stop accelerating and, if the vehicle has a manual transmission, push in the clutch
An acceleration skid ends when the drive wheels stop pushing, so easing off the throttle and disengaging the clutch lets them regain grip.
-
22. During a right turn in a tractor-trailer, what are you looking for in the right hand mirror?
Show answer
Answer B: Whether the trailer will clear the curb and whether anything has moved alongside you
The right mirror is what tells you how close the trailer wheels are running to the curb and whether a vehicle or a cyclist has slipped into the space on your right.
-
23. A driver behind you wants to pass and you can see that the road ahead is clear. What should you do?
Show answer
Answer B: Do not signal the other driver to pass; let that driver decide when it is safe
Directing other drivers can cause a crash if you misjudge the gap, so leave the decision to the driver who is passing.
-
24. Under federal rules, what is required of a commercial driver who wants to use a mobile phone while driving?
Show answer
Answer B: The phone must be hands-free and started with no more than a single button press, and it must not be held
Federal rules ban texting and hand-held phone use while driving a commercial vehicle; reaching for, holding or dialing a phone is a violation.
-
25. Why do cracked spring hangers or badly worn shackles matter?
Show answer
Answer A: They allow the axle to shift out of its correct position under the vehicle
Hangers and shackles hold the spring, and therefore the axle, in place, so when they fail the axle can move and the vehicle may become uncontrollable.
-
26. A roadside test shows a commercial driver has measurable alcohol in the system but below 0.04. What happens?
Show answer
Answer C: The driver is placed out of service for 24 hours
Any measurable alcohol while on duty results in an immediate 24 hour out of service order, even when the concentration is under the 0.04 limit.
-
27. Which shock absorber condition is a defect?
Show answer
Answer C: A shock that is leaking, broken or disconnected at either mounting
A shock that has lost its fluid or its mounting no longer damps the suspension, so the wheel bounces and loses contact with the road.
-
28. Apart from the legal duty, what is the main practical reason for a thorough pre-trip inspection?
Show answer
Answer A: It finds problems that could cause a breakdown or a crash before the vehicle is on the road
A defect found in the yard is an inconvenience, while the same defect found at highway speed can be a crash, so the inspection is where problems are cheapest to fix.
-
29. Your vehicle stalls on a railroad crossing and a train is coming. What should you do?
Show answer
Answer C: Get out at once and move toward the train, well off to one side
Leave the vehicle immediately and move at an angle toward the oncoming train, so that wreckage thrown forward by the impact travels away from you.
-
30. What are the rules for using your turn signal before a turn or lane change?
Show answer
Answer A: Signal early, keep the signal on until the turn is finished, then cancel it
An early, continuous signal tells others what you plan to do; cancelling afterward keeps the signal from misleading them.
-
31. What should you check about the fuel tank during the walkaround?
Show answer
Answer A: That it is securely mounted, the cap is on tight and there are no leaks
A loose tank or a missing cap can spill fuel, and any fuel leak is a fire hazard that makes the vehicle unsafe to drive.
-
32. The scale shows that your combination is over the legal gross weight. Why will sliding the tandems not fix it?
Show answer
Answer B: Because sliding the axles changes where the weight sits, not how much there is
Repositioning axles redistributes weight between axle groups; when the total is too high, freight has to come off the vehicle.
-
33. You are stopped in traffic on a steep upgrade behind another truck. How much space should you leave in front?
Show answer
Answer A: Enough that you can pull away without rolling back into the vehicle behind you
Room ahead lets you get moving smoothly on a grade instead of having to hold the vehicle perfectly still or roll back toward the traffic behind.
-
34. How can a driver tell that a shipment includes hazardous materials?
Show answer
Answer B: The shipping paper describes them and the packages carry hazard warning labels
Hazardous materials are identified on the shipping paper with their shipping name and hazard class, and the packages themselves carry labels showing the hazard.
-
35. An unblocked article is 8 feet long and weighs 900 pounds. How many tiedowns does the federal rule require?
Show answer
Answer B: Two
Only an article that is 5 feet or shorter and 1,100 pounds or lighter can be held with a single tiedown; anything longer than 5 feet needs at least two whatever it weighs.
-
36. Which brake lining condition must be reported?
Show answer
Answer C: Linings that are worn thin, loose, cracked or soaked with oil or grease
Linings must have enough material left and must be securely attached and clean, because a thin, loose or contaminated lining cannot deliver its share of braking.
-
37. After starting the engine, how quickly should the oil pressure gauge come up to its normal range?
Show answer
Answer B: Within a few seconds
Oil pressure should build within seconds of starting; if it stays low, the engine is not being lubricated and should be shut down.
-
38. When a helper guides you while backing, what should be agreed on before you start?
Show answer
Answer D: A set of hand signals, especially the signal that means stop
The driver and helper must agree on signals in advance, above all the stop signal, because they usually cannot hear each other.
-
39. A Nevada commercial driver is convicted of a traffic offense in another state. What must the driver do?
Show answer
Answer A: Notify the home state and the employer within 30 days of the conviction
Federal rules applied by Nevada require a commercial driver to notify the home state and the employer of any traffic conviction received in another state, using DMV form CDL 005 within 30 days.
-
40. Your brakes are starting to fade on a mountain downgrade and a sign shows an escape ramp one mile ahead. What should you do?
Show answer
Answer B: Plan to use the ramp instead of trying to reach the bottom
Fading brakes on a grade only get worse, and the ramp exists precisely so a driver does not have to gamble on the rest of the descent.
-
41. Within what distance should high beams be lowered at night?
Show answer
Answer D: Within about 500 feet of an oncoming vehicle and within about 500 feet of a vehicle you are following
High beams blind other drivers at close range, so they are lowered at roughly the same distance whether the other vehicle is coming toward you or is ahead of you.
-
42. Why must cargo also be held down against vertical movement and not only against sliding?
Show answer
Answer D: Because a load that bounces can jump the blocking and slacken its own tiedowns
Rough road makes an unrestrained article lift; every bounce lets it move a little and works the tiedowns loose until nothing is holding it.
-
43. Why does a driver use pull-ups while backing into a tight space?
Show answer
Answer C: To pull forward and start the approach again when the angle is going wrong
Stopping, pulling ahead and repositioning fixes a bad angle safely, and there is nothing wrong with needing more than one attempt.
-
44. Where are the OVERSIZE LOAD signs normally carried on a vehicle moving under such a permit?
Show answer
Answer A: On the front and the rear of the vehicle
The warning signs face the traffic that meets the load and the traffic that comes up behind it, so they go on the front and the rear.
-
45. How should the headlamps be checked during the pre-trip inspection?
Show answer
Answer A: By switching on both low beam and high beam and confirming each one works outside
Both beams are separate circuits, so each is switched on in turn and confirmed from outside the vehicle where the lamps can actually be seen.
-
46. What is the correct way to make a right turn in a long vehicle?
Show answer
Answer D: Keep the rear of the vehicle close to the curb and swing wide only as you complete the turn
Swinging left before a right turn invites another driver to move into the gap on your right, so any extra width is taken as the turn is finished.
-
47. Why is a sudden, sharp lane change dangerous in a loaded heavy vehicle?
Show answer
Answer D: The vehicle can lean far enough to roll over, especially when the load sits high
A quick swerve throws the weight of a tall, heavy load sideways, and a rollover can begin before the tires ever slide.
-
48. What does the commercial driver manual tell you to do with the parking brake when you leave your vehicle?
Show answer
Answer B: Apply the parking brake every time you leave the vehicle
The manual is explicit that the parking brake goes on whenever the driver leaves the vehicle, because once nobody is at the controls it is the only thing holding it.
-
49. A vehicle carries placards on its front, rear and both sides. What is the main purpose of those placards?
Show answer
Answer C: To tell emergency responders and other people what hazard the cargo presents
Placards warn everyone around the vehicle, especially emergency responders, about the kind of hazard the cargo presents.
-
50. Why does a load of hanging meat in a refrigerated trailer require special care in curves?
Show answer
Answer D: The meat swings and has a high center of gravity, which makes the trailer unstable
Hanging meat is heavy, sits high and swings, so the trailer can tip in a curve or on a ramp taken at normal speed.