New York DMV CDL General Knowledge Practice Test 1
Test 1 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 New York test.
- Questions50
- Correct to pass40
- Passing score80%
- Minimum age18 years
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1. Which parts of total stopping distance can a driver shorten simply by staying alert and looking far ahead?
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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.
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2. How do you get more engine braking from an automatic transmission on a downgrade?
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Answer B: Select a lower range before starting down
Locking the transmission into a lower range keeps engine speed high enough to hold the vehicle back and spares the service brakes.
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3. A carrier operates commercial vehicles every day of the week. What weekly on-duty limit applies to its drivers?
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Answer A: 70 hours in 8 consecutive days
The limit is 60 hours in 7 consecutive days for a carrier that does not run every day, and 70 hours in 8 consecutive days for one that does.
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4. Why should you never shift gears while crossing railroad tracks?
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Answer A: You could miss the gear or stall and be stuck on the tracks
A stalled or coasting vehicle on the tracks has no way to clear quickly, so choose the gear before the crossing and do not shift until you are across.
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5. What must the driver confirm about the required emergency equipment before a trip?
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Answer A: That it is in place, in working order and ready to be used
Federal rules require the driver to be satisfied that the emergency equipment is present and ready, because it is needed at the worst possible moment.
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6. What tells you that an air suspension bag has a problem?
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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.
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7. What is the basic rule about backing a large vehicle?
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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.
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8. Which components on a typical engine are driven by belts that must be checked for wear and tension?
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Answer D: The alternator, the water pump and, on many vehicles, the air compressor
Belts drive accessories such as the alternator, the water pump and the air compressor, so one failed belt can take out charging, cooling or air supply.
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9. Why must a bent, cracked or badly seated lock ring be reported?
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Answer D: It can come off under pressure and let the tire and rim separate violently
The lock ring holds the assembly together against the full pressure of the tire, so a damaged ring can release with enough force to kill.
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10. For an unblocked article longer than 10 feet, the minimum is two tiedowns plus how many more?
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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.
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11. What is the purpose of the torque rods or radius rods you check on the suspension?
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Answer A: They hold the axle in alignment with the frame under braking and acceleration
Torque rods resist the twisting and fore and aft forces on the axle, so a cracked or missing rod lets the axle move out of alignment.
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12. Why should you never back under a trailer whose landing gear is resting on soft or muddy ground?
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Answer C: The landing gear can sink or collapse and the trailer can drop or tip over
Soft ground lets the landing gear sink under the load being transferred to it, and a trailer that drops or topples during coupling is extremely dangerous.
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13. What is the danger of letting engine speed climb past the top of the rated rpm range before you shift?
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Answer B: You can damage the engine, so the shift should be made before that point
Every engine has a rated operating range; running above it can cause serious engine damage, so the upshift belongs at the top of that range, not beyond it.
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14. Which road users are hardest to see at night?
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Answer C: Pedestrians and cyclists in dark clothing
People on foot or on a bicycle carry no lights of their own in many cases, so they appear only when the headlights reach them.
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15. You pick up a trailer that another driver dropped in the yard. What must you do before pulling it?
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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.
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16. How are New York commercial knowledge test questions presented?
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Answer C: As multiple choice with one correct answer out of three
New York commercial knowledge questions are multiple choice and each offers three answer choices, of which one is correct.
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17. Why is backing toward the driver side preferred?
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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.
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18. At 55 mph, about how far does a vehicle travel during a typical 3/4 second perception time plus 3/4 second reaction time, before the brakes even begin to work?
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Answer C: About 120 feet
Each 3/4 second at 55 mph covers about 60 feet, so perception and reaction together use up roughly 120 feet before braking starts.
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19. How does a load carried high in the trailer affect safe speed through a curve?
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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.
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20. You are driving past a park where children are playing close to the curb. What is the correct assumption?
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Answer A: A child may run into the street without looking
Children act on impulse and do not judge traffic well, so a driver has to expect one to enter the road and slow down in advance.
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21. Under federal rules, which commercial vehicles must stop at every railroad crossing before proceeding?
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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.
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22. You hear air escaping from a trailer tire during the pre-trip. What should you do?
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Answer C: Have it repaired or replaced before the vehicle is driven
An audible leak means the tire is failing now, and federal rules do not allow a vehicle to be operated on a flat or leaking tire.
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23. On the Interstate System, what is the federal maximum weight allowed on a single axle?
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Answer A: 20,000 pounds
Federal limits for the Interstate System cap one single axle at 20,000 pounds.
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24. Regular mirror checks during a long trip can reveal which developing problem?
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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.
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25. Most rollovers of loaded trucks on exit and entrance ramps happen for which reason?
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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.
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26. What does the federal bridge formula do?
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Answer C: It reduces the weight allowed on a group of axles as those axles get closer together
Axles bunched together concentrate the load on a short span of a bridge, so the formula lowers the allowable weight as the spacing shrinks.
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27. You are asked to drive a truck loaded with enough hazardous materials to require placards. What must you have?
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Answer C: A hazardous materials endorsement on your commercial driver license
Driving a vehicle that must be placarded requires the H endorsement, which involves a separate knowledge test and a security background check.
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28. May a commercial driver use a hand-held phone while stopped at a red light?
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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.
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29. What happens to a commercial driver's license if that driver refuses a chemical test a second time within five years?
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Answer A: The CDL is permanently revoked
A second chemical test refusal within five years results in permanent revocation of a New York commercial driver license.
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30. What must the motor carrier do about a defect listed on a driver vehicle inspection report?
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Answer D: Repair it, or certify that repair is not needed, before the vehicle is dispatched again
A reported defect must be corrected, or certified as not needing correction, and that certification is what the next driver reads before taking the vehicle.
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31. A vehicle becomes unsafe while you are already on the road. What does the federal rule allow?
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Answer A: Continuing only to the nearest place where repairs can safely be made
If stopping where you are would be more dangerous than moving, the rule allows you to reach the nearest place where the vehicle can safely be repaired, and no further.
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32. Why should high beams not be used in fog?
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Answer A: The light reflects back off the droplets and blinds you
Fog is made of water droplets that scatter light straight back at the driver, so a stronger beam makes the wall of glare worse rather than better.
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33. A load overhangs the rear of the trailer. What must the driver check before leaving?
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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.
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34. Total stopping distance is made up of which parts?
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Answer A: Perception distance, reaction distance and braking distance
The vehicle travels while the hazard is recognized, while the driver moves to the pedal, and again while the brakes slow the vehicle.
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35. How does a driver keep a vehicle with a manual transmission from rolling back when starting on an upgrade?
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Answer D: Partly engage the clutch before the right foot leaves the brake, or hold the vehicle with the parking brake until the engine pulls
Something has to hold the vehicle during the instant the foot moves from the brake to the accelerator, and that is either the clutch at its engagement point or the parking brake.
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36. You are the first to arrive at a crash. What is the correct order of actions?
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Answer C: Protect the area, notify the authorities, care for the injured
Preventing a second crash comes first, because an unprotected scene puts the injured and the helpers in more danger than the original collision.
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37. 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?
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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.
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38. What score passes each New York commercial driver knowledge test?
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Answer B: 80 percent
Every commercial knowledge test in New York, including endorsement tests, is passed at 80 percent, and there is no fixed limit on retakes.
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39. When is a road surface usually most slippery during a rain shower?
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Answer A: Just after the rain starts, when water mixes with oil and dirt on the surface
The first rain lifts oil and dust into a slick film that has not yet been washed away, so the road is more slippery than it will be later.
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40. What is the first step of the standard seven-step vehicle inspection?
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Answer C: A general overview of the vehicle, including the last inspection report
The routine opens with a walk-up overview of the vehicle and a review of the previous inspection report so known defects are addressed first.
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41. At highway speed, looking 12 to 15 seconds ahead means looking about how far down the road?
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Answer B: About a quarter of a mile
Twelve to fifteen seconds of travel is roughly a quarter of a mile at highway speed, while the same amount of time is about one block in slow city traffic.
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42. What should a driver assume about the height posted at a bridge or an overpass?
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Answer B: That it may be wrong, because repaving or packed snow can leave less clearance than the sign shows
Resurfacing and packed snow raise the road under the structure, so the real clearance can be lower than the posted figure.
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43. A delivery van is stopped in the right lane ahead with its flashers on. What should you expect?
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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.
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44. Why is a leak in the exhaust system especially dangerous in cold weather?
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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.
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45. The coolant temperature gauge climbs above its normal range on a long grade. What is the correct response?
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Answer C: Stop when it is safe to do so and find the cause before going on
Rising coolant temperature signals a fault such as a lost belt, a leak or a blocked radiator, and continuing can turn a repair into a destroyed engine.
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46. The car in the next lane still has snow covering most of its windows. What should you assume?
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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.
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47. What is checked about the engine cooling system during the engine compartment inspection?
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Answer C: That the coolant level is adequate and the radiator and hoses are not leaking
A low coolant level or a leaking hose leads to overheating, which can stop the vehicle in a place where stopping is dangerous.
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48. Your right wheels drop off the pavement onto a soft shoulder. What is the correct recovery?
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Answer A: Stay on the shoulder, ease off the accelerator, brake gently only once speed is down to about 20 mph, then steer back sharply and countersteer at once
Bringing speed down on the shoulder first avoids a violent sideways jolt, and countersteering the instant the tires are back on the pavement keeps the vehicle out of the next lane.
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49. How does a front tire failure usually feel to the driver?
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Answer D: The steering suddenly becomes heavy and pulls to one side
A failed front tire loads the steering and makes the wheel feel heavy, while a rear tire failure shows up as the back end swaying.
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50. While checking the in-cab gauges after start-up, what should the coolant temperature gauge do?
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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.