New Hampshire NH DMV CDL General Knowledge Practice Test 6
- Questions50
- Correct to pass40
- Passing score80%
- Minimum age18 years
-
1. Which of these counts as a serious traffic violation for a commercial driver license holder?
Show answer
Answer C: Speeding 15 miles per hour or more above the limit
Excessive speeding, reckless driving, improper lane changes, following too closely and texting while driving are all serious traffic violations.
-
2. What testing does New Hampshire require when transferring a valid out-of-state CDL of the same class and endorsements?
Show answer
Answer C: No written tests, except for a hazardous materials endorsement, which needs fingerprinting and the hazmat knowledge test
New Hampshire generally does not require written tests to transfer a valid out-of-state CDL with the same class and endorsements, but a hazardous materials endorsement requires fingerprinting and the hazmat knowledge test.
-
3. Some commodities have their own detailed securement rules on top of the general ones. Which list is made up of such commodities?
Show answer
Answer C: Logs, metal coils, paper rolls, concrete pipe and crushed vehicles
The cargo securement rules add specific requirements for particular commodities, including logs, dressed lumber, metal coils, paper rolls, concrete pipe, intermodal containers, vehicles, crushed cars, roll on containers and large boulders.
-
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. Why must the driver of a large vehicle keep it centered in its lane?
Show answer
Answer B: The vehicle needs the full width of the lane
A commercial vehicle is close to lane width already, so any drift takes part of the vehicle into the next lane or onto the shoulder.
-
6. Why should the radio, the fan and other noisy equipment be switched off during a required stop at a railroad crossing?
Show answer
Answer C: So that an approaching train can be heard
The rules require the driver to look and listen along the track, and on a double track crossing a passing train can hide a second one, so hearing matters as much as seeing.
-
7. 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.
-
8. 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.
-
9. Why is a leaking exhaust system on a commercial vehicle dangerous to the driver?
Show answer
Answer B: It can let carbon monoxide reach the cab, where it can poison the occupants
Exhaust gas contains carbon monoxide, which has no smell and dulls the driver judgment long before it becomes obvious that anything is wrong.
-
10. 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.
-
11. The engine oil pressure gauge falls toward zero while you are driving. What should you do?
Show answer
Answer C: Stop as soon as it is safe to do so and shut the engine down
Loss of oil pressure destroys an engine in a very short time, so the correct response is to stop and shut down rather than to drive on.
-
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. An overpass you have driven under before now has a fresh layer of pavement on the road below it. Why does that matter?
Show answer
Answer B: The new layer raises the road and reduces the clearance
Repaving lifts the road surface, so the real clearance under a structure can be less than the height posted on it.
-
14. Why does a cracked frame rail or cross member make a vehicle unsafe?
Show answer
Answer B: The frame carries the whole load, and a crack can spread until the structure fails
The frame is the backbone that supports the body, the load and the running gear, so a crack in it is a structural failure that grows with every mile.
-
15. 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.
-
16. A dock crew loads all of the freight at the very back of a 48 foot van trailer. What are the two consequences?
Show answer
Answer A: The steering axle is relieved of weight and steering becomes light, and the trailer axles may go over the limit
Weight placed far to the rear lifts weight off the front of the combination, so the steering goes light while the trailer axles take too much of the load.
-
17. Why does the commercial driver manual tell you to look far down the road instead of only at the vehicle ahead?
Show answer
Answer D: So you can adjust smoothly instead of braking hard at the last moment
A heavy vehicle cannot react quickly, so early information lets you slow gradually rather than make a sudden stop or swerve.
-
18. 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.
-
19. 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.
-
20. What tells you that an air suspension bag has a problem?
Show answer
Answer B: The bag is leaking or damaged, or the vehicle sits unevenly on that side
An air bag that leaks or is cut lets that corner of the vehicle settle, which throws the load onto the other suspension parts and changes the ride height.
-
21. How does a load carried high in the trailer affect safe speed through a curve?
Show answer
Answer B: It raises the rollover risk, so the speed must be lower
A high center of gravity lets the vehicle tip long before the tires lose their grip, so height of the load directly limits curve speed.
-
22. 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.
-
23. What is the minimum age to apply for a New Hampshire commercial driver license?
Show answer
Answer C: 18 years
The NH DMV states that drivers must be at least 18 years old to apply for a commercial driver license.
-
24. Which items belong to the trailer part of the walkaround inspection?
Show answer
Answer D: Landing gear, doors, tires, wheels, lights, reflectors, frame and cargo securement
The trailer has its own running gear, lighting, structure and load, and all of it is the responsibility of the driver pulling it.
-
25. 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.
-
26. 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.
-
27. Where is the yellow antilock brake malfunction lamp on a trailer, and what does it mean if it stays lit?
Show answer
Answer D: On the left side, at the front or rear corner, and it means the antilock function may not be working
Trailers carry the yellow lamp on the left side, and a lamp that stays on after the bulb check means the antilock function may be lost even though the normal brakes still work.
-
28. How are the headlights, marker lights and turn signals checked during the seven-step inspection?
Show answer
Answer A: The engine is shut off, the parking brake is set, the lights are switched on and then checked from outside the vehicle
The lights are switched on with the vehicle secured, then the driver walks around and confirms each lamp actually works and is clean.
-
29. What does the driver check in the final step of the seven-step inspection?
Show answer
Answer A: Hydraulic brake leaks where those brakes are fitted, then the parking brake and the service brakes
The last step is done with the engine started: test for hydraulic leaks on vehicles with hydraulic brakes, then prove that the parking brake holds and that the service brakes stop the vehicle.
-
30. 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.
-
31. 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.
-
32. Two tires in a dual set have noticeably different diameters. Why is that a problem?
Show answer
Answer C: The larger tire carries more than its share of the load and can be overloaded
The taller tire touches the road first and takes most of the weight, so it runs overloaded and hot while the smaller one does little work.
-
33. As a long vehicle goes around a corner, how do the rear wheels travel compared with the front wheels?
Show answer
Answer A: They follow a tighter path, closer to the inside of the turn
The rear wheels off-track toward the inside of the turn, and the longer the vehicle the bigger the difference, which is why the front must swing wide enough to keep the rear off the curb.
-
34. What is the driver responsible for when a load is covered with a tarp?
Show answer
Answer C: Fastening it so it cannot flap free, block a mirror, or come off in the wind
A tarp that works loose can tear away, block the driver view or the view of others, and become a hazard for the traffic behind.
-
35. After the first inspection of a trip, how often must cargo securement be checked again?
Show answer
Answer D: Every 3 hours or 150 miles or at each change of duty status, whichever happens first
The load must be re-checked at whichever of those points arrives first, so a loosening tiedown is found long before it fails.
-
36. Most rollovers of loaded trucks on exit and entrance ramps happen for which reason?
Show answer
Answer B: The ramp was taken faster than the load could tolerate
A posted ramp speed is set for cars, and a loaded trailer with a high center of gravity can roll at a speed a car would take easily.
-
37. Where on a tire is tread depth measured?
Show answer
Answer C: In a major tread groove, away from any tie bar or wear indicator
Depth is taken in a major groove and away from the raised tie bars and wear indicators, which would give a shallower and misleading reading.
-
38. 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.
-
39. What does New Hampshire law say about using an amateur or citizens band radio while driving?
Show answer
Answer A: It is lawful, notwithstanding any other provision of law
RSA 265:105 expressly makes it lawful to use an amateur or citizens band radio, radio telephone, radio telegraph equipment or other electronic receiving device while driving.
-
40. What does it mean to overdrive your headlights at night?
Show answer
Answer D: Driving so fast that you cannot stop within the distance lit by your headlights
You must be able to stop inside the distance you can see; at night that distance is limited by the headlights, so speed must be lowered to match.
-
41. A car ahead of you keeps drifting within its lane and moving unevenly. What should you assume?
Show answer
Answer C: The driver may be distracted, lost or impaired
Unsteady lane keeping is a classic clue to a driver who is not in full control, so the safe response is to keep back and give plenty of room.
-
42. 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.
-
43. Which factors determine a safe speed for a long, steep downgrade?
Show answer
Answer C: The steepness and length of the grade, the weight of the vehicle and cargo, and the road and weather conditions
Gravity, weight and traction all decide how fast a heavy vehicle can safely descend, which is why signs often post lower speeds for trucks on grades.
-
44. 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.
-
45. You are pulling a loaded pneumatic dry bulk trailer and approach an exit ramp posted at 35 mph. What is the safest approach?
Show answer
Answer C: Slow to well below the posted speed before the ramp begins
A dry bulk trailer carries its weight high and the load can move, so the ramp speed posted for a car is far too fast and the slowing must be finished before the curve.
-
46. Which of these is a major cause of skids in heavy vehicles?
Show answer
Answer C: Over-braking, over-steering, over-acceleration or driving too fast for conditions
Skids happen when the tires are asked for more grip than the road can give, which happens through braking, steering or accelerating too hard or simply too much speed.
-
47. What must be checked about the cargo doors and any tarpaulin before a trip?
Show answer
Answer B: That the doors are closed and latched and that any tarp is tied down securely
An unlatched door or a loose tarp can swing open or tear free at speed, spilling cargo or blocking the view of the traffic behind you.
-
48. 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.
-
49. How soon must warning devices be placed after a commercial vehicle stops on the traveled part or the shoulder of a highway?
Show answer
Answer D: As soon as possible and in any case within 10 minutes
The hazard warning flashers go on immediately and the warning devices must be in place as soon as possible, never later than 10 minutes after stopping.
-
50. A commercial driver is convicted of two serious traffic violations within three years. What is the result?
Show answer
Answer D: Disqualification for 60 days
Two serious traffic violations in a three year period bring a 60 day disqualification, and a third in the same period raises it to 120 days.