Nevada DMV CDL General Knowledge Practice Test 7
- Questions50
- Correct to pass40
- Passing score80%
- Minimum age18 years
-
1. What are you looking for on the brake drums during the walkaround?
Show answer
Answer B: Cracks, dents and any oil or grease that has reached the friction surface
A cracked or badly scored drum can break apart under braking heat, and oil or grease on the friction surface destroys the braking effort at that wheel.
-
2. While checking the in-cab gauges after start-up, what should the coolant temperature gauge do?
Show answer
Answer C: Rise gradually to the normal operating range
A healthy cooling system warms the engine slowly; a gauge that shoots up or stays cold points to a problem with the thermostat, coolant or sensor.
-
3. A delivery van is stopped in the right lane ahead with its flashers on. What should you expect?
Show answer
Answer C: Someone may step into your lane from in front of it
A stopped delivery vehicle hides the space in front of it, and that is exactly where a person carrying a package is likely to walk out.
-
4. Why should the radiator cap never be removed while the engine is hot?
Show answer
Answer A: The cooling system is under pressure and scalding coolant can be sprayed out
A hot cooling system holds pressurized coolant above its normal boiling point, so releasing the cap can throw boiling liquid and steam at whoever is holding it.
-
5. The only way into a customer yard forces you to back toward the right, or blind, side of the vehicle. What should you do?
Show answer
Answer D: Use a helper and get out to check the path more often than you normally would
Blind side backing is allowed but far riskier, so it calls for a spotter you can see and for repeated checks of the path on foot.
-
6. At the scale your tractor drive axles are overweight while the trailer axles have room. Sliding the trailer tandems forward will do what?
Show answer
Answer C: Move weight off the drive axles and onto the trailer axles
Sliding the trailer tandems forward brings the rear support closer to the load, so the trailer axles pick up more weight and the drive axles carry less; sliding them rearward does the opposite.
-
7. How is the fluid level in an automatic transmission usually checked?
Show answer
Answer A: With the engine running, following the procedure in the operator manual
Most automatic transmissions are designed to be checked with the engine running, and the operator manual gives the exact conditions for that vehicle.
-
8. Taking your eyes off the road for about five seconds at highway speed means traveling roughly how far unseen?
Show answer
Answer A: About the length of a football field
At highway speed a five second glance away covers roughly 100 yards, which is far more road than any driver can afford to travel blind.
-
9. Apart from the risk of stalling, why is rolling backwards when starting on an upgrade so serious in a heavy vehicle?
Show answer
Answer D: You can strike the vehicle behind you, which is often much closer than you think
You cannot see how close the vehicle behind has stopped, and even a short roll back is enough to hit it.
-
10. For a modern truck with low-friction parts and a streamlined shape, which gear should be used going down a grade?
Show answer
Answer D: A gear lower than the one needed to climb the same grade
Newer trucks roll more freely than older ones, so the old rule of using the climbing gear no longer holds; a lower gear is needed for enough engine braking.
-
11. How often must every commercial motor vehicle receive a periodic inspection?
Show answer
Answer C: At least once every twelve months
Federal rules require each commercial motor vehicle to pass a periodic inspection at least once in every twelve month period.
-
12. A load overhangs the rear of the trailer. What must the driver check before leaving?
Show answer
Answer D: That the overhang is marked as required, with flags or lamps as conditions demand
A projecting load has to be made visible to other drivers, with flags in daylight and lamps when lights are required, so nobody runs into what they cannot see.
-
13. 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.
-
14. Besides the hours when the law requires them, when should headlights be switched on?
Show answer
Answer A: Any time visibility is poor, such as in rain, fog or at dusk
Headlights are used to be seen as much as to see, so they belong on whenever light or weather makes the vehicle harder to spot.
-
15. Your vehicle begins to hydroplane on a wet road. What should you do?
Show answer
Answer B: Release the accelerator and push in the clutch so the wheels can turn freely and regain grip
Hydroplaning tires are riding on water; slowing without braking lets them settle back onto the road and grip again.
-
16. You are strapping down a load with sharp metal edges on a flatbed. What should you use?
Show answer
Answer D: Edge protection between the strap and the sharp edges so the tiedown is not cut
Sharp edges cut or wear through a strap under tension, so edge protectors are required wherever a tiedown could be damaged.
-
17. How can a driver restart the 60 or 70 hour on-duty limit?
Show answer
Answer B: Take 34 or more consecutive hours off duty
A period of 34 or more consecutive hours off duty resets the 60 or 70 hour calculation so the driver can begin a new period.
-
18. You are backing with a helper guiding you and the helper drops out of sight in your mirror. What should you do?
Show answer
Answer B: Stop until you can see the helper again
If you cannot see the helper you cannot receive a signal to stop, so the only safe action is to halt until visual contact is restored.
-
19. You have backed into the same loading bay every week for a year. How often should you still get out and walk to the rear before backing?
Show answer
Answer D: Every time, since the area can change while you are away from it
A familiar space is no guarantee; vehicles, pallets, people and overhead obstructions appear between one visit and the next, so you check on every occasion.
-
20. You find a defect during the pre-trip inspection. What must happen before the vehicle is driven?
Show answer
Answer C: It must be repaired, or the vehicle must not be driven
Writing a defect down does not make the vehicle safe; a defect that affects safe operation has to be corrected before the trip starts.
-
21. What is the most common cause of a front-wheel skid, where the vehicle keeps going straight even though you turn the wheel?
Show answer
Answer B: Driving too fast for the conditions
A front-wheel skid usually comes from too much speed for the traction available; the only cure is to let the vehicle slow down and stop turning or braking so hard.
-
22. You are hauling a load of steel plate that is well within every weight limit but is stacked five feet high on a flatbed. What is the main concern?
Show answer
Answer A: The center of gravity is high, so the rig will roll more easily in a curve
Legal weight does not make a load safe; height raises the center of gravity and it is height, not weight alone, that decides how readily the vehicle rolls over.
-
23. Cargo falls from your trailer and causes a crash behind you. Who is likely to answer for it?
Show answer
Answer C: The driver and the carrier, since securing the load on the road is their duty
Whoever loaded the vehicle, the driver and the carrier are responsible for the load being secure while it is on the road.
-
24. A driver is tailgating you, honking and making gestures. What is the best response?
Show answer
Answer A: Do not make eye contact, ignore the gestures and give the driver room to get past
Engaging an aggressive driver only escalates the situation; the safest move is to stay calm, avoid eye contact and let the driver get by.
-
25. Why should both outside mirrors be checked over and over while backing?
Show answer
Answer B: Each mirror covers only part of the path and neither covers the blind spots, so people and objects can appear without warning
Working both mirrors in turn is the only way to follow the whole path of a vehicle you cannot see behind.
-
26. Why is a leak in the exhaust system especially dangerous in cold weather?
Show answer
Answer A: Carbon monoxide can build up inside a closed cab
In winter the windows are shut and the heater is running, so exhaust gas that escapes early can reach the driver and cause drowsiness or worse.
-
27. What must be checked on a sliding fifth wheel during the inspection?
Show answer
Answer B: That it is locked in position and not so far forward that the trailer can hit the cab
A slider that is unlocked can move under braking, and one set too far forward lets the trailer strike the cab when the tractor turns sharply.
-
28. How long must a Nevada Commercial Learner Permit be held before the skills test?
Show answer
Answer A: At least 14 days from the date of initial issuance
Nevada requires the Commercial Learner Permit to be held for 14 days from initial issuance before the applicant may take the skills test.
-
29. What is the coupling device weight rating on a vehicle?
Show answer
Answer A: The most weight that the coupling on the vehicle is rated to pull
The coupling device rating is a limit on how much weight the coupling may tow, and it is one of the ratings that has to be respected when a combination is loaded.
-
30. You are about to cross a long, high bridge with a light load in gusty wind. What should you do?
Show answer
Answer C: Slow down and be ready for a sudden push
Wind is strongest where a bridge leaves the shelter of the land, and lower speed gives you time to correct when the first gust hits.
-
31. Why must the steering wheel be moved only a small amount at a time while backing?
Show answer
Answer B: Because a small turn of the wheel produces a large change at the rear of the vehicle
In reverse, the effect of the steering is greatly magnified at the back of the vehicle, so a small correction is usually all that is needed.
-
32. You miss a gear while double clutching and the transmission is stuck in neutral. What should you do?
Show answer
Answer B: Return to neutral, release the clutch, bring engine speed to match road speed and try again
Forcing the lever damages the gears; matching the engine speed to the road speed lets the gear engage cleanly on the next try.
-
33. Your brakes have failed and you decide to use the parking brake to slow down. Why should you hold the release button or lever while doing so?
Show answer
Answer D: So you can release the brake at once if the wheels lock and the vehicle starts to skid
The parking brake can lock the wheels; keeping your hand on the release lets you let go the moment a skid starts and regain control.
-
34. 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.
-
35. What is the minimum tread depth for tires in positions other than the steering axle?
Show answer
Answer A: 2/32 inch
Drive and trailer tires must keep at least 2/32 inch of tread in a major groove, measured away from tie bars and fillets.
-
36. Which winter preparation matters most for keeping the road in view?
Show answer
Answer D: Working wipers, washer fluid and a working defroster
Slush and road spray coat the windshield within minutes in winter, so wipers, washer fluid and the defroster are what keep any view at all.
-
37. How do you confirm that the coupling is locked before pulling out of the yard?
Show answer
Answer D: By locking the trailer brakes and pulling gently forward against them
The tug test loads the coupling in the direction that would pull it apart, so if the jaws are not closed on the kingpin you find out at walking pace.
-
38. What alcohol concentration triggers the 185-day administrative revocation for the holder of a Nevada commercial driver license?
Show answer
Answer B: .04 percent or more
Nevada's administrative action revokes the license for 185 days at .08 percent for ordinary drivers, but at .04 percent or more for a commercial driver license holder.
-
39. Under federal rules, which commercial vehicles must stop at every railroad crossing before proceeding?
Show answer
Answer D: Passenger buses and placarded hazardous materials vehicles
Buses carrying passengers and vehicles required to display hazardous materials placards must stop at crossings, while other commercial vehicles slow and check.
-
40. 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.
-
41. 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.
-
42. What does the tachometer on the dashboard of a heavy truck show?
Show answer
Answer D: How fast the engine is turning, in revolutions per minute
The tachometer reads engine speed in rpm, which is what a driver uses to judge shift points in a vehicle with a manual transmission.
-
43. A fire starts in the cargo area of a van trailer. Why should you keep the doors closed until firefighters arrive?
Show answer
Answer D: Opening the doors lets in air that feeds the fire
A fire in a closed van is starved of oxygen; opening the doors gives it the air it needs to flare up.
-
44. You are given a ratchet strap with a deep cut along one edge. What should you do?
Show answer
Answer C: Do not use it; a damaged tiedown cannot be relied on to hold its rated load
Cuts, burns, knots and broken stitching weaken a strap far below its marked working load limit, so it must be taken out of service.
-
45. At what time of day do drowsy driving crashes occur most often?
Show answer
Answer A: Between midnight and 6 a.m.
The body clock makes people sleepiest in the early morning hours, which is when most fatigue-related crashes happen.
-
46. What is the payload of a truck?
Show answer
Answer C: The weight of the cargo the vehicle is carrying, that is the loaded weight less the empty weight
Payload is what is left of the legal or rated weight once the weight of the empty vehicle is taken off, and it is the weight of cargo that can be carried.
-
47. 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.
-
48. Why is braking while in a curve dangerous in a heavy vehicle?
Show answer
Answer A: The wheels lock more easily and the vehicle can skid
Tires already using their grip to turn have little left for braking, so hard braking in a curve locks the wheels; slow down before the curve instead.
-
49. Why are the windshield wipers on the pre-trip list even before a trip in fine weather?
Show answer
Answer C: Because weather can change and a wiper failure leaves the driver without a clear view
Rain, spray or mud can arrive at any point in a long trip, and a wiper that fails then leaves the driver with no way to clear the windshield.
-
50. How is free play in the steering wheel measured during the inspection?
Show answer
Answer B: By turning the wheel until the front wheels just start to move and noting the movement
Play is the movement at the rim that produces no movement at the road wheels, so it is measured by turning until the wheels first respond.