New Mexico MVD CDL General Knowledge Practice Test 8
- Questions50
- Correct to pass40
- Passing score80%
- Minimum age18 years
-
1. Why is backing toward the driver side preferred?
Show answer
Answer C: You can watch the rear of the vehicle directly through the side window
Backing to the left lets the driver look out the window and see the rear of the vehicle directly instead of relying on a mirror alone.
-
2. If a New Mexico driver's traffic violation happened while driving a commercial vehicle, how does the resulting CDL disqualification relate to their regular license revocation or suspension?
Show answer
Answer D: It can run for a different length of time than, and in addition to, the regular revocation or suspension
New Mexico may impose a CDL disqualification alongside an ordinary license revocation or suspension for the same violation, and the two can run for different lengths of time.
-
3. When should the horn of a commercial vehicle be used?
Show answer
Answer C: Only when it is needed to avoid a crash
An air horn is loud enough to startle other road users, so it is a warning device rather than a way to comment on other drivers.
-
4. 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.
-
5. The rear wheels of your vehicle lock during braking and the rear starts to slide sideways. What should you do first?
Show answer
Answer A: Stop braking so the rear wheels can roll again, then steer quickly in the direction you want to go
Locked wheels have no side grip; releasing the brakes restores traction and then countersteering brings the vehicle back into line.
-
6. Your axle weights are legal, but the tires on that axle are rated below the weight it is carrying. What controls?
Show answer
Answer B: The lower figure, so the tires may not be loaded beyond their marked rating
You may never exceed the rating marked on a tire, even when the axle limit would allow more, because an overloaded tire builds heat and can fail.
-
7. What does restriction K mean on a New Mexico commercial driver license?
Show answer
Answer B: The driver may only operate a commercial vehicle in intrastate commerce
Restriction K limits the holder to commercial driving inside New Mexico, so interstate trips are not authorized.
-
8. Dry bulk tanks call for extra caution mainly because of what?
Show answer
Answer C: A high center of gravity combined with a load that can shift
Dry bulk loads ride high and can move inside the tank, which makes the vehicle easier to tip in a curve.
-
9. 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.
-
10. You are stopped in a line of traffic behind a car. How much space should you leave in front of you?
Show answer
Answer C: Enough to see where the rear tires of that car meet the road
That amount of space lets you pull around the vehicle ahead if it stalls and absorbs some of the shock if you are struck from behind.
-
11. 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.
-
12. What are you checking when you pull the engine oil dipstick during the pre-trip?
Show answer
Answer A: That the oil level is within the safe operating range marked on the stick
The dipstick shows whether there is enough oil to lubricate and cool the engine, and a level outside the safe range must be corrected before driving.
-
13. You are backing a tractor-trailer in a straight line and the trailer starts to drift to the left. What is the standard correction?
Show answer
Answer D: Turn the top of the steering wheel a little to the left, toward the drift
Small corrections made in the direction the trailer is drifting bring it back into line; large or opposite movements make the drift worse.
-
14. Who must sign a driver vehicle inspection report?
Show answer
Answer D: The driver who prepared it
The report is the driver statement about the condition of the vehicle at the end of the day, so the driver signs it.
-
15. 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.
-
16. You are pulling away from a curb in a 65 foot combination. Besides traffic, what must you watch?
Show answer
Answer B: The trailer wheels, which stay close to the curb and can strike it or an object on it
Because of off-tracking, the rear wheels follow a tighter path than the front, so they stay near the curb while the cab is already out in the lane.
-
17. 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.
-
18. You drive a 40 foot straight truck at 50 miles per hour in good conditions. What following distance does the rule of thumb call for?
Show answer
Answer A: 5 seconds
One second for every 10 feet of vehicle length gives 4 seconds, and one extra second is added for speeds above 40 miles per hour.
-
19. Where are regrooved, recapped or retreaded tires not allowed on a truck or truck tractor?
Show answer
Answer C: On the front steering wheels
Regrooved and retreaded tires are prohibited on the front wheels of a truck or truck tractor because a steering tire blowout is extremely difficult to manage.
-
20. During uncoupling, when may the fifth wheel locking lever be released?
Show answer
Answer D: Only after the landing gear is down and taking the weight of the trailer
The landing gear has to be supporting the trailer before the lock is released; otherwise the trailer nose can drop as soon as the tractor pulls out.
-
21. Why should a driver avoid traveling alongside another vehicle for any length of time?
Show answer
Answer D: You lose your escape route and you may be sitting in the other driver blind spot
Running beside someone leaves nowhere to move if you have to change lanes, and the other driver may not know you are there at all.
-
22. Why must you never coast down a hill in neutral or with the clutch pushed in?
Show answer
Answer C: You lose the braking effect of the engine and your brakes may overheat and fail
Engine braking is what keeps a heavy vehicle in check on a grade; coasting throws it away and leaves the service brakes to do all the work until they overheat.
-
23. 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.
-
24. A chain rated at 6,600 pounds is fitted with a hook rated at 4,700 pounds. What is the working load limit of that assembly?
Show answer
Answer A: 4,700 pounds, the rating of the weakest part
An assembly is only as strong as its weakest component, so hooks, binders and links all count and the lowest rating governs.
-
25. An automatic transmission is left in its normal drive position as the vehicle rolls down a long grade. What does it tend to do?
Show answer
Answer A: Shift up as road speed rises, so engine braking falls away
An automatic left in drive keeps upshifting as speed builds, which is the opposite of what you want on a grade; that is why the driver must select a low range.
-
26. Under federal safety rules, what must the driver of a commercial vehicle do before starting a trip?
Show answer
Answer A: Be satisfied that the vehicle is in safe operating condition
The driver is responsible for inspecting the vehicle and must be satisfied it is in safe operating condition before the trip begins.
-
27. What is the best practice when fog is thick enough to hide the road ahead?
Show answer
Answer B: Slow down before entering the fog, and if visibility is too poor, pull off into a rest area or truck stop until it improves
The safest choice in heavy fog is not to be driving in it, and if you are already in it your speed has to come down before your visibility does.
-
28. Regular mirror checks during a long trip can reveal which developing problem?
Show answer
Answer D: Smoke coming from a tire or from a wheel
Overheating tires, wheel bearings and brakes usually show as smoke long before anything appears on the dash, and mirrors are where a driver sees it.
-
29. Which set of emergency equipment must be carried on a commercial motor vehicle?
Show answer
Answer D: A fire extinguisher, spare electrical fuses unless the vehicle has circuit breakers, and warning devices
The required kit is a properly charged and rated fire extinguisher, spare fuses when the vehicle uses them, and warning devices for a stopped vehicle.
-
30. Why must tiedowns be rechecked during a trip even when they were tight at the start?
Show answer
Answer C: Road vibration and cargo movement can loosen them as the miles go by
Straps and chains settle and loosen as the vehicle bounces and the cargo shifts slightly, so the load must be rechecked at the required intervals.
-
31. What is normally required in order to move an over-width or over-length load?
Show answer
Answer B: A special permit along with warning devices such as flags and signs
Oversize movements need a permit plus marking devices, and travel is often limited to certain hours or routes.
-
32. How much free play in the steering wheel is enough to make a vehicle hard to steer and should be reported?
Show answer
Answer B: More than 10 degrees, roughly 2 inches of movement at the rim of a 20 inch wheel
Excess play means steering input is lost before the wheels respond, and more than about 10 degrees is treated as a defect.
-
33. You must drive well below the speed of surrounding traffic, for example when climbing a steep grade with a heavy load. What should you do?
Show answer
Answer B: Turn on the four-way flashers to warn following traffic, where state law allows it
Flashers warn faster traffic that a slow-moving vehicle is ahead, which helps prevent rear-end crashes; some states restrict their use while moving, so check the local rule.
-
34. 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.
-
35. What actually lowers the amount of alcohol in the bloodstream?
Show answer
Answer B: Time
The liver removes alcohol at a fixed rate, so nothing but the passage of time reduces blood alcohol concentration.
-
36. Why should you avoid using your lights to tell a following driver that it is safe to pass you?
Show answer
Answer B: You may misjudge the gap and the driver will act on your signal
The manual warns against signaling others to pass, because the responsibility for a head-on crash then rests on a judgment you could easily get wrong.
-
37. What happens to braking distance when speed is doubled?
Show answer
Answer C: It becomes about four times longer
Braking distance grows with the square of speed, so doubling the speed multiplies both the braking distance and the force of an impact by about four.
-
38. 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.
-
39. 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.
-
40. On the Interstate System, what are the federal maximums for a tandem axle group and for gross vehicle weight?
Show answer
Answer B: 34,000 pounds and 80,000 pounds
The federal Interstate limits allow 34,000 pounds on a tandem axle group and 80,000 pounds gross.
-
41. Which step of the seven-step inspection method comes immediately after checking the engine compartment?
Show answer
Answer D: Start the engine and inspect the inside of the cab
Once the hood is closed the driver moves to the driver seat, starts the engine and checks gauges, controls and warning devices before going any further.
-
42. 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.
-
43. Which vehicles are most likely to get hung up on a raised railroad crossing?
Show answer
Answer A: Low-slung units such as car carriers and lowboys
Vehicles with low ground clearance or a long wheelbase can bottom out on a humped crossing and become stuck on the tracks.
-
44. 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.
-
45. The car in the next lane still has snow covering most of its windows. What should you assume?
Show answer
Answer C: That driver cannot see you and may move into your lane
A driver whose view is blocked cannot see the vehicles around, so you should assume you are invisible and stay out of that vehicle path.
-
46. 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.
-
47. 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.
-
48. 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.
-
49. 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.
-
50. Where should a trailer be dropped, and what else does the driver do before pulling out from under it?
Show answer
Answer C: On solid level ground, with the trailer wheels chocked if it may roll
A dropped trailer must sit on ground that will carry the landing gear without sinking, and chocks stop it rolling once the tractor and its air supply are gone.