New Jersey MVC CDL General Knowledge Practice Test 7
- Questions50
- Correct to pass40
- Passing score80%
- Minimum age18 years
-
1. What do the U-bolts on a leaf spring suspension do?
Show answer
Answer A: They clamp the spring assembly to the axle so it cannot move
U-bolts hold the spring pack tight against the axle, and a loose or broken U-bolt lets the axle slide out of place under load.
-
2. You are not certain that your loaded vehicle will clear a low overpass. What should you do?
Show answer
Answer A: Take another route rather than risk it
There is no safe way to guess at a clearance, and striking a bridge endangers everyone on and under it, so the only correct choice is a different route.
-
3. On a two lane road carrying traffic in both directions, where do the three warning devices go?
Show answer
Answer C: About 10 feet from the vehicle on the traffic side, 100 feet behind and 100 feet ahead
Traffic can approach from either direction, so one device goes close to the vehicle and one is placed about 100 feet away in each direction.
-
4. Experienced commercial drivers scan the road ahead by roughly how much travel time?
Show answer
Answer B: About 12 to 15 seconds
Looking 12 to 15 seconds ahead gives a heavy vehicle enough room to slow or change lanes smoothly instead of reacting late.
-
5. What phone rule applies to a New Jersey school bus driver at the wheel?
Show answer
Answer B: Both handheld and hands-free devices are banned while the bus is in operation
A school bus driver may not use a handheld or hands-free phone while operating the bus, except in an emergency or when the bus is parked in a safe area off the highway.
-
6. You need to pull off onto the shoulder because of a problem with the load. How should you communicate that to other drivers?
Show answer
Answer D: Signal the move, then switch on the four-way flashers once stopped
Other drivers need a signal before you leave the lane and a clear warning once the vehicle is stopped near the traffic lanes.
-
7. Who may remove an out-of-service sticker from a commercial vehicle?
Show answer
Answer B: Only an authorized person, and only after the defect that caused it has been repaired
The sticker stays on the vehicle until the repairs are made and an authorized person removes it, so nobody can simply peel it off and drive away.
-
8. Where do you find the maximum weight a tire can safely carry?
Show answer
Answer D: Stamped on the sidewall of the tire itself
Each tire is marked with the greatest weight it can carry at a stated inflation pressure, and the load on an axle must stay within the total for its tires.
-
9. 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.
-
10. What should you do before backing into a space you have not used before?
Show answer
Answer A: Get out and walk around to check the path, the clearance and any obstacles
Walking the area first reveals low obstructions, soft ground and objects that never appear in the mirrors.
-
11. Your vehicle is stopped just past a hill or curve that hides it from approaching traffic. How should the warning devices be adjusted?
Show answer
Answer A: Move the rearmost device farther back, up to 500 feet, so drivers are warned before the obstruction
When a hill or curve blocks the view, the farthest device is moved back beyond the obstruction so approaching drivers see the warning in time.
-
12. You are moving an oversized load under a permit that requires a pilot vehicle. What is the pilot vehicle there to do?
Show answer
Answer B: Warn other traffic and check the route ahead for clearances and hazards
Escort or pilot vehicles warn approaching traffic and scout the route for low bridges, narrow spots and other hazards that a wide or long load cannot pass.
-
13. 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.
-
14. What does mountain driving demand that flat country driving does not?
Show answer
Answer D: Lower gears and constant allowance for gravity
In the mountains gravity works for you on the climb and against you on the descent, so gear selection and speed control matter far more than on level road.
-
15. You need fuel and the canopy over the pumps is low. What is the safe way to handle the clearance?
Show answer
Answer B: Stop and check the height at the entrance and at the way out before committing
Clearance can differ at the entry, under the canopy and at the exit, and a sloping approach changes the effective height, so both ends have to be checked.
-
16. You are drifting in the lane, yawning constantly and cannot remember the last few miles. What is the only reliable cure?
Show answer
Answer C: Stopping in a safe place and sleeping
Those are classic drowsiness warning signs, and nothing except sleep repays the sleep the body is missing.
-
17. What tells a driver when to shift up in a vehicle with a manual transmission?
Show answer
Answer C: Engine speed in rpm together with road speed
Shift points are judged from engine rpm and road speed, using the operating range the manufacturer specifies for that engine.
-
18. Where should a driver expect fog to form first?
Show answer
Answer D: In low ground, near water and in valleys
Cool moist air settles in low places, so fog patches appear in hollows, river valleys and near lakes before they appear anywhere else.
-
19. During the walkaround you find the reflective conspicuity tape along the trailer caked with road grime. What should you do?
Show answer
Answer B: Clean it, because dirty reflective material cannot make the trailer visible at night
Reflective sheeting only works if light can reach it and bounce back, so a dirty strip leaves the trailer effectively unmarked to approaching traffic.
-
20. An enforcement officer inspects your vehicle at the roadside and attaches an out-of-service sticker. What may you do?
Show answer
Answer C: Nothing until the defect is repaired; the vehicle may not be driven
An out-of-service order means the vehicle is unsafe, and no schedule, load or destination allows it to be driven before the defect is corrected.
-
21. You are hauling an open box of loose gravel. What does that load require?
Show answer
Answer A: A cover, so that material cannot blow off or spill onto the road
Loose material that can be blown or spilled has to be covered so it does not come out of the body and strike traffic behind.
-
22. You are backing into a yard where electrical wires cross overhead. What is the main concern?
Show answer
Answer C: The wires may hang lower than the top of your vehicle
Overhead space has to be checked like any other space around the vehicle, because wires and cables are often lower than they look from the cab.
-
23. You are about to back across a quiet street into a driveway. Which of these is good practice before you start to move?
Show answer
Answer B: Turn on the four-way flashers and sound the horn to alert anyone nearby
Warning other road users and pedestrians before a reverse maneuver gives them the chance to stop or move clear before the vehicle starts back.
-
24. An intermodal container is being carried on an ordinary flatbed rather than on a container chassis. What does that mean for securement?
Show answer
Answer B: It must be secured with tiedowns that meet the container securement requirements
A container carried on a vehicle that is not fitted with integral locking devices has to be secured to the deck with tiedowns that satisfy the rules for containers.
-
25. On a scale, your loaded truck is well under the gross weight limit, but one axle is above the limit for that axle. What does this mean?
Show answer
Answer D: The vehicle is overloaded and the load must be shifted or reduced before you drive on
Each axle and axle group has its own limit and each must be respected; being under the gross limit does not excuse an overloaded axle.
-
26. When speed doubles, what happens to braking distance?
Show answer
Answer D: It becomes roughly four times as long
Braking distance rises with the square of speed, so twice the speed needs about four times the distance to stop.
-
27. 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.
-
28. During the vehicle overview, what should the driver look for on the ground under the vehicle?
Show answer
Answer B: Fresh puddles of oil, coolant, grease or fuel
New stains on the ground are the earliest sign of a leak, so the overview includes a look underneath before anything is opened or started.
-
29. You pick up a trailer that another driver dropped in the yard. What must you do before pulling it?
Show answer
Answer B: Inspect it yourself, because you are responsible for the whole vehicle you drive
Responsibility follows the driver who moves the vehicle, and a trailer that has stood in a yard may have lost air, developed a flat tire or been damaged.
-
30. Compared with a fully loaded one, an empty truck under hard braking will often do what?
Show answer
Answer A: Need a longer distance to stop because traction is poor
Stiff suspension and little weight over the tires reduce grip, so the wheels lock early and the vehicle can take longer to stop.
-
31. What is axle weight?
Show answer
Answer C: The weight carried to the ground by one axle or one set of axles
Axle weight describes how the load is shared among the axles that carry it to the road, not how much the whole vehicle weighs.
-
32. You are unsure whether your vehicle will fit through a narrow gate. What should you do?
Show answer
Answer A: Stop, get out and look, and take another route if the space is not clearly enough
Clearance is never guessed at from the seat; you look at it on foot and go round rather than trying a gap that may be too tight.
-
33. How should a driver use brakes fitted with an antilock system during an emergency stop?
Show answer
Answer C: Brake as usual and keep enough pressure to stay in control while steering around the hazard
The system only works when the brakes are applied hard enough for it to act, so the driver keeps pressure on and steers while the system prevents lockup.
-
34. Which wheel or rim condition must be treated as a defect during the walkaround?
Show answer
Answer C: Cracks, illegal welded repairs, or missing and loose lug nuts
Cracked or welded rims and missing or loose fasteners can let a wheel separate from the vehicle and must be corrected before driving.
-
35. What speed and gear should be used when backing a large vehicle?
Show answer
Answer B: As slowly as possible, in the lowest reverse gear
Backing slowly in the lowest reverse gear keeps the vehicle under precise control and leaves time to correct the path.
-
36. Rust streaks are running outward from the lug nuts on one wheel. What does this most likely indicate?
Show answer
Answer C: The lug nuts may be loose
Rust trails spreading from the nuts are a classic sign that the nuts have worked loose and the wheel has been moving on the studs.
-
37. You are inspecting the vehicle alone and need to confirm that the stop lights work. Which method is correct?
Show answer
Answer A: Have a helper press the brake pedal, or apply the brake in a way that keeps it on while you check from outside
Stop lights are checked from outside the vehicle while the brakes are applied, so a helper or a brake held on is needed.
-
38. What is the basic rule about backing a large vehicle?
Show answer
Answer B: Avoid backing whenever there is another way
Backing is dangerous because you cannot see everything behind you, so the manual tells drivers to plan routes and parking that avoid it.
-
39. 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.
-
40. 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.
-
41. A strap is a little too long, so a driver ties a knot in it to take up the slack. Is that acceptable?
Show answer
Answer C: No, tiedowns must not contain knots
A knot destroys the rated strength of a tiedown, so the rules do not allow knotted securement devices; the excess is taken up by the winch or ratchet instead.
-
42. What condition should the fifth wheel be in before you back under a trailer?
Show answer
Answer C: Jaws open, plate greased, and the fifth wheel tilted down toward the rear
The jaws have to be open to take the kingpin, the plate must be lubricated to prevent hard steering, and the fifth wheel is tilted down at the rear so the trailer apron can ride up onto it.
-
43. What is the purpose of blocking placed against cargo on a trailer deck?
Show answer
Answer B: To fill the space around the cargo so it cannot slide
Blocking is shaped to fit snugly against the cargo and fastened to the deck, removing the room the load would need in order to move.
-
44. 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.
-
45. A commercial vehicle stops on the shoulder of an undivided two-lane road that carries traffic in both directions. Where do the warning devices go?
Show answer
Answer B: Within 10 feet of the vehicle, plus 100 feet to the front and 100 feet to the rear
On a two-way road the devices must mark the vehicle itself and warn traffic approaching from each direction, and they must be in place within ten minutes.
-
46. You press on a drive belt and it deflects far more than the others. What does that suggest?
Show answer
Answer C: The belt is too loose and the part it drives may not work properly
A belt with excessive play slips on its pulleys, so the accessory it drives turns too slowly or not at all under load.
-
47. You find one lug nut missing from a wheel that has ten studs. What should you do?
Show answer
Answer C: Treat it as a defect and have it repaired before the vehicle is driven
Every missing fastener loads the others more heavily, and wheel separations usually begin with one nut that nobody replaced.
-
48. What is the minimum tread depth required in every major groove of a steering axle tire?
Show answer
Answer D: 4/32 inch
Federal rules set a higher tread minimum for front steering tires than for other positions because a steering tire failure is far harder to control.
-
49. You are told a posted bridge ahead has a weight limit lower than your gross weight. What must you do?
Show answer
Answer C: Take a route that avoids it, because a posted limit is a legal limit
A posted structure limit must be obeyed exactly as any other weight limit, so a heavier vehicle has to be routed around it.
-
50. 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.