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NH CDL General Knowledge study materials
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NH CDL General Knowledge practice questions

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Question 1Vehicle Inspection and Basic Control

During a pre-trip inspection of a hydraulic brake system, how long should the air pressure loss be checked by holding the brake pedal down with the engine running?

  1. Until the low air warning buzzer sounds
  2. For 5 seconds while watching the gauge for any drop
  3. Only long enough to confirm the pedal feels firm
  4. For one minute while watching the gauge for a pressure drop Correct answer.

Explanation

For a vehicle with hydraulic brakes, the pre-trip inspection requires holding the brake pedal down with the engine running and watching the gauge for one minute. A pressure drop during that minute indicates a leak or failing component that must be fixed before driving.

Question 2Vehicle Inspection and Basic Control

You are inspecting a tractor-trailer and must check the service brakes. Which action correctly tests the slack adjusters on a vehicle with manual slack adjusters?

  1. Chock the wheels, release the parking brake, and pull each slack adjuster to check for more than about one inch of free play at the push rod Correct answer.
  2. Press the brake pedal and listen for air escaping at the chamber
  3. Release the parking brake and watch the push rods retract fully
  4. Pull each slack adjuster by hand and confirm it moves freely with no resistance

Explanation

With the wheels chocked and parking brake released, grasp each slack adjuster and pull it; excessive free play at the push rod (roughly one inch or more) means the brakes need adjustment. This check is part of the pre-trip inspection for manually adjusted brakes.

Question 3Vehicle Inspection and Basic Control

When performing the pre-trip inspection, where should you check the coolant level?

  1. By removing the radiator cap while the engine is hot
  2. At the surge tank or radiator sight glass with the engine cool Correct answer.
  3. By checking the overflow puddle under the engine
  4. Only by reading the dashboard temperature gauge

Explanation

Coolant should be checked at the surge tank or sight glass when the engine is cool, which avoids scalding and gives an accurate level. Removing a radiator cap on a hot engine can release pressurized steam and cause serious burns.

Question 4Vehicle Inspection and Basic Control

During the pre-trip inspection, you check the steering system. Which observation indicates a problem that must be corrected before driving?

  1. The steering wheel returns smoothly after a turn
  2. The power steering fluid is at the full mark on the dipstick
  3. The steering wheel has slight free play of about 10 degrees
  4. The steering box is loose or the tie rod ends have excessive play Correct answer.

Explanation

A loose steering box or excessive play in the tie rod ends means the steering is not responding precisely and could fail. Any looseness in these components must be repaired before the vehicle is operated.

Question 5Vehicle Inspection and Basic Control

You are checking tire condition during a pre-trip inspection. Which condition requires the vehicle to be placed out of service?

  1. A tread depth of 3/32 inch on a rear tire
  2. A tread depth of 4/32 inch on a front steering tire Correct answer.
  3. A small stone lodged in the tread groove
  4. A properly inflated tire with even wear

Explanation

Front steering tires on a commercial vehicle must have at least 4/32 inch of tread depth; less than that is a defect. Rear tires have a lower minimum, so 3/32 inch on a rear tire is acceptable.

Question 6Vehicle Inspection and Basic Control

What is the correct way to check the oil level during a pre-trip inspection?

  1. By looking at the oil filter housing
  2. With the engine off and the vehicle on level ground, using the dipstick Correct answer.
  3. With the engine running and the dipstick removed
  4. By watching the oil pressure gauge while idling

Explanation

The oil level is checked with the engine off and the vehicle on level ground so the reading on the dipstick is accurate. Checking with the engine running or on a slope gives a false reading.

Question 7Vehicle Inspection and Basic Control

When backing a tractor-trailer, which technique helps you avoid a jackknife?

  1. Back with the trailer at a sharp angle to shorten the distance
  2. Back quickly so the trailer does not have time to swing
  3. Use the mirrors and back slowly, correcting with small steering movements Correct answer.
  4. Turn the steering wheel sharply in the opposite direction of the trailer

Explanation

Backing slowly while watching both mirrors and making small steering corrections keeps the trailer under control and reduces the chance of a jackknife. Sharp angles and fast backing make the trailer swing uncontrollably.

Question 8Vehicle Inspection and Basic Control

You are driving a loaded tractor-trailer on a downgrade. Which action best controls your speed without overheating the brakes?

  1. Shift to neutral and use the service brakes continuously
  2. Select a lower gear before the grade and use the engine brake plus light, steady braking Correct answer.
  3. Apply the brakes hard at the top of the grade and hold them
  4. Rely on the trailer hand valve to slow the combination

Explanation

Selecting a lower gear before the downgrade lets engine braking share the load, and light steady brake applications keep the drums from overheating. Continuous or hard braking on a long grade can cause fade and loss of control.

Question 9Vehicle Inspection and Basic Control

What is the purpose of the pre-trip inspection of the coupling system on a tractor-trailer?

  1. To verify the trailer lights are working
  2. To test the trailer spring brakes
  3. To check the air pressure in the trailer tires
  4. To confirm the fifth wheel is greased and the kingpin is fully locked Correct answer.

Explanation

The coupling inspection confirms the kingpin is fully seated and locked in the fifth wheel and that the assembly is properly greased. A properly locked coupling prevents the trailer from separating from the tractor.

Question 10Vehicle Inspection and Basic Control

During the pre-trip inspection, you must check the air compressor and air system. Which result indicates the air system is functioning properly?

  1. Air pressure remains constant regardless of engine speed
  2. Air pressure builds from 85 to 100 psi only when the engine is at high idle
  3. Air pressure drops when the engine is started
  4. Air pressure builds from 85 to 100 psi within 45 seconds at normal idle Correct answer.

Explanation

A properly functioning air system builds pressure from 85 to 100 psi within 45 seconds at normal engine idle. Slower buildup suggests a compressor or leak problem that must be repaired.

Question 11Vehicle Inspection and Basic Control

When performing a pre-trip inspection, what should you check on the exhaust system?

  1. That the exhaust exits at the rear of the tractor
  2. That the exhaust pipe is painted
  3. That the system is secure, undamaged, and not leaking Correct answer.
  4. That the muffler is the largest component

Explanation

The exhaust system must be secure, free of damage, and not leaking, since leaks can allow carbon monoxide into the cab. Loose or damaged exhaust parts are a safety defect.

Question 12Vehicle Inspection and Basic Control

You are inspecting the lights on a tractor-trailer. Which check confirms the trailer clearance lights are working?

  1. Turn on the headlights and walk around to see the marker lights illuminate Correct answer.
  2. Honk the horn and watch for a flash
  3. Engage the turn signal and check the front lights
  4. Press the brake pedal and check the tail lights

Explanation

Turning on the headlights or marker light switch and walking around the vehicle lets you confirm the trailer clearance and marker lights are lit. This is part of the lighting portion of the pre-trip inspection.

Question 13Vehicle Inspection and Basic Control

What is the correct procedure for testing the parking brake on a tractor-trailer during the pre-trip inspection?

  1. Test the parking brake only after the air pressure drops below 60 psi
  2. Release the parking brake and roll backward
  3. Set the parking brake and try to pull forward slowly to see if the vehicle moves Correct answer.
  4. Set the parking brake while the engine is off only

Explanation

With the parking brake set, gently try to pull forward; if the vehicle moves, the parking brake is not holding and must be repaired. This confirms the brake can hold the vehicle when parked.

Question 14Vehicle Inspection and Basic Control

During a pre-trip inspection, you find a broken leaf spring or a missing spring hanger. What should you do?

  1. Place the vehicle out of service until the suspension is repaired Correct answer.
  2. Note it and continue the trip, checking it again at the next stop
  3. Inflate the tires to maximum pressure to compensate
  4. Reduce the load and drive at lower speed

Explanation

A broken leaf spring or missing hanger compromises the suspension and can cause loss of control or axle misalignment. The vehicle must be placed out of service until the defect is repaired.

Question 15Vehicle Inspection and Basic Control

When checking the engine compartment during a pre-trip inspection, which item should be verified for the belts?

  1. That the belts are tight and not cracked or frayed Correct answer.
  2. That only one belt is installed
  3. That the belts are the correct color
  4. That the belts are slightly loose to allow slippage

Explanation

Belts should be tight and free of cracks or fraying so they can drive the alternator, water pump, and other accessories. A loose or damaged belt can slip or break and cause a breakdown.

Question 16Vehicle Inspection and Basic Control

You are checking the air brake system during the pre-trip inspection. What does it mean if the low air pressure warning activates at 60 psi?

  1. The warning system is working as designed Correct answer.
  2. The compressor has failed completely
  3. The trailer supply valve is closed
  4. The parking brake will not release

Explanation

The low air pressure warning must activate before the pressure drops below 60 psi, so activation at that point confirms the warning system works. This alerts the driver before braking ability is compromised.

Question 17Vehicle Inspection and Basic Control

When performing the pre-trip inspection, how should you check the mirrors and windshield?

  1. Check only that the windshield wipers work
  2. Confirm the mirrors are adjusted, clean, and unbroken and the windshield is clear and free of cracks Correct answer.
  3. Check that the windshield has a tint strip
  4. Check that the mirrors are folded in for travel

Explanation

Mirrors must be clean, properly adjusted, and free of cracks, and the windshield must be clear and undamaged for good visibility. Impaired visibility is a safety defect that must be corrected.

Question 18Vehicle Inspection and Basic Control

During the pre-trip inspection, you check the trailer air lines. Which condition indicates the lines are properly connected?

  1. The lines are crossed and hanging loosely
  2. The lines are secure, not crossed, and the glad hands are locked Correct answer.
  3. The lines are taped together at the coupling
  4. The lines are disconnected to prevent air loss

Explanation

Trailer air lines must be securely connected with locked glad hands and must not be crossed, since crossed lines cause the trailer brakes to malfunction. Loose or crossed lines are a defect.

Question 19Vehicle Inspection and Basic Control

What is the recommended way to check for air leaks in the brake system during the pre-trip inspection?

  1. Only check for leaks when the low pressure warning sounds
  2. Listen for leaks with the engine running and the brakes released, then apply the brakes and listen again Correct answer.
  3. Check for leaks by watching the fuel gauge
  4. Spray soapy water only on the tires

Explanation

With the engine running and the brakes released, listen for leaks, then apply the brakes and listen again; leaks often appear only when the system is pressurized. Soapy water can also be used on fittings to reveal bubbles.

Question 20Vehicle Inspection and Basic Control

Before driving, you must check the trailer spring brakes. Which action confirms they apply automatically when air pressure is lost?

  1. Open the trailer supply valve and watch the pressure gauge rise
  2. Shut off the engine and listen for the brakes to set
  3. Pull the red trailer air supply valve out and listen for the spring brakes to apply Correct answer.
  4. Release the parking brake and roll forward

Explanation

Pulling out the red trailer air supply valve exhausts air from the trailer, and the spring brakes should apply automatically. This confirms the emergency braking feature works if the trailer separates or loses air.

Question 21Vehicle Inspection and Basic Control

When starting a heavy vehicle, what is the correct sequence before moving?

  1. Fasten the seat belt, check mirrors, release the parking brake, and move slowly Correct answer.
  2. Shift into a high gear and release the clutch
  3. Release the parking brake, shift into gear, and accelerate quickly
  4. Honk the horn, release the brake, and accelerate

Explanation

Before moving, secure the seat belt, check the mirrors for clearance, release the parking brake, and pull away slowly. This sequence confirms it is safe to move and prevents an unintended roll.

Question 22Vehicle Inspection and Basic Control

You are driving a tractor-trailer and must make a right turn. Which technique helps avoid hitting the curb or a vehicle on the right?

  1. Turn sharply from the right lane without checking mirrors
  2. Speed up through the turn to clear the intersection quickly
  3. Swing wide to the left before turning and check the right mirror as you turn Correct answer.
  4. Turn from the far-left lane across traffic

Explanation

Swinging wide to the left before a right turn gives the trailer room to clear the curb, and watching the right mirror confirms the trailer clears obstacles. Rushing or turning from the wrong lane risks a crash.

Question 23Vehicle Inspection and Basic Control

What is the correct way to check the fifth wheel jaws during the pre-trip inspection?

  1. Pull the release handle to see if it moves
  2. Confirm the kingpin is greased only
  3. Look under the trailer to confirm the jaws are closed around the kingpin and the safety latch is engaged Correct answer.
  4. Check that the fifth wheel is painted

Explanation

Visually inspecting the fifth wheel from under the trailer confirms the jaws have closed around the kingpin and the safety latch is engaged. A properly closed coupling prevents trailer separation.

Question 24Vehicle Inspection and Basic Control

During the pre-trip inspection, how should you check the brake drums and linings on a vehicle with air brakes?

  1. Check that the drums are hot to the touch
  2. Check that the drums are painted and the linings are dry
  3. Check that the drums are cracked and the linings are worn
  4. Check that the drums are free of cracks and the linings have adequate thickness Correct answer.

Explanation

Brake drums must be free of cracks and the linings must have sufficient thickness to stop the vehicle. Cracked drums or worn linings reduce braking ability and must be repaired.

Question 25Shifting, Backing, and Turning

You are driving a tractor-trailer on a straight, dry road and need to change lanes. What is the safest way to begin steering into the new lane?

  1. Accelerate hard during the turn to pull the trailer straight
  2. Use a slow, smooth steering input and check the mirrors as the trailer follows Correct answer.
  3. Turn the steering wheel sharply so the trailer follows quickly
  4. Brake hard while turning to keep the rig tight

Explanation

A tractor-trailer steers from the rear, so the trailer cuts the corner and follows the path of the cab. Steering inputs should be smooth and gradual, and you must watch the mirrors to confirm the trailer is tracking correctly. Sharp inputs or sudden braking while turning can cause the trailer to swing or the rig to roll.

Question 26Shifting, Backing, and Turning

When backing a tractor-trailer, which technique gives you the most control and visibility?

  1. Back only toward the driver's side and use the mirrors
  2. Back quickly to reduce the time the trailer wanders
  3. Rely on the backup camera alone and ignore the mirrors
  4. Use a helper as a spotter and back slowly with the mirrors Correct answer.

Explanation

Backing a large combination vehicle is safest at a slow walk, using both mirrors and a spotter who stays in view. A spotter can see blind areas the driver cannot and can stop the maneuver if needed. Backing quickly or trusting a single view source reduces reaction time and hides hazards.

Question 27Shifting, Backing, and Turning

You must make a right turn in a tractor-trailer at a tight urban intersection. What should you do before starting the turn?

  1. Swing wide to the left first, then turn right Correct answer.
  2. Stay in the right lane and turn from the rightmost position
  3. Move to the left lane and turn from there
  4. Turn from the center lane to give the trailer room

Explanation

A tractor-trailer's rear wheels track inside the path of the front wheels, so the trailer cuts the corner. To keep the trailer off the curb and out of the way of vehicles on your right, swing wide to the left before turning right. Turning from a tight right position risks the trailer running over the curb or striking a pedestrian or vehicle.

Question 28Shifting, Backing, and Turning

Why does a tractor-trailer need extra room when making a left turn at an intersection?

  1. The trailer brakes engage later than the cab brakes
  2. The trailer is lighter than the cab
  3. The steering axle turns more sharply than a car's
  4. The rear wheels of the trailer track inside the front wheels Correct answer.

Explanation

Off-tracking means the trailer's rear wheels follow a path closer to the inside of the turn than the front wheels. On a left turn this can put the trailer over the curb or into oncoming lanes if you do not allow enough room. Drivers must swing wide and check mirrors throughout the turn.

Question 29Shifting, Backing, and Turning

You are backing a trailer and the trailer starts to drift to the left. To correct it while backing, which way should you turn the steering wheel?

  1. Turn the wheel to the right
  2. Turn the wheel to the left Correct answer.
  3. Brake hard and stop backing
  4. Hold the wheel straight and continue backing

Explanation

When backing, the trailer moves in the direction you turn the wheel. If the trailer drifts left, turning the wheel left steers the trailer back to the right relative to your view. Small corrections made early keep the trailer tracking straight.

Question 30Shifting, Backing, and Turning

What is the main reason to check your mirrors frequently while driving a tractor-trailer in traffic?

  1. To check the trailer's tire pressure
  2. To confirm the trailer is tracking properly and to see vehicles in blind spots Correct answer.
  3. To monitor fuel consumption
  4. To watch the trailer brakes for overheating

Explanation

Mirrors are the primary tool for confirming the trailer is following correctly and for spotting vehicles in the large blind areas around a rig. Frequent mirror checks let you detect a drifting trailer or a passing vehicle before it becomes a hazard. Mirrors do not measure brake heat, tire pressure, or fuel use.

Question 31Shifting, Backing, and Turning

You are driving a loaded tractor-trailer and need to make a sharp right turn onto a narrow street. Which action best protects pedestrians on the right corner?

  1. Honk continuously and turn without slowing
  2. Check the right mirror and blind area for pedestrians, then turn slowly with a wide swing Correct answer.
  3. Turn from the left lane to avoid the corner entirely
  4. Speed up through the turn to clear the corner quickly

Explanation

Pedestrians near the right corner are at risk because the trailer cuts inside the turn. Checking the right mirror and blind area before and during the turn, combined with a slow wide swing, keeps the trailer clear of the curb. Speed and horn use do not replace a proper visual check.

Question 32Shifting, Backing, and Turning

When backing a tractor-trailer with a spotter, where should the spotter position themselves?

  1. In front of the cab to watch the front bumper
  2. Directly behind the trailer to guide the driver
  3. In the driver's mirror view on the side the trailer is backing toward Correct answer.
  4. Inside the cab next to the driver

Explanation

A spotter must stay visible in the driver's mirror on the side the trailer is moving toward. From there the spotter can see the path and signal the driver to stop if needed. Standing directly behind the trailer or inside the cab defeats the purpose of the spotter.

Question 33Shifting, Backing, and Turning

You are backing a trailer into a loading dock on your right side. The trailer begins to swing too far to the right. What is the best corrective action?

  1. Stop and restart the maneuver from the beginning
  2. Turn the wheel right to bring the trailer back
  3. Accelerate to pull the trailer straight
  4. Turn the wheel left to bring the trailer back Correct answer.

Explanation

When backing toward the right and the trailer swings too far right, turning the wheel left steers the trailer back toward the desired line. Corrections should be small and made early. Accelerating or restarting does not correct the trailer's path and can worsen the situation.

Question 34Shifting, Backing, and Turning

A tractor-trailer is making a right turn and the driver notices the trailer's rear wheels are about to cross the curb. What should the driver do?

  1. Stop, back up slightly, and re-approach with a wider swing Correct answer.
  2. Turn the wheel harder to the right
  3. Continue the turn and let the trailer ride the curb
  4. Accelerate to lift the trailer over the curb

Explanation

If the trailer is about to hit the curb, stopping and re-approaching with a wider swing keeps the trailer clear. Riding the curb can damage tires and the trailer and may strike pedestrians or objects. Accelerating or turning harder increases the risk.

Question 35Shifting, Backing, and Turning

What does the term "off-tracking" describe when turning a tractor-trailer?

  1. The trailer brakes applying later than the cab brakes
  2. The steering wheel returning to center after a turn
  3. The trailer swaying at highway speed
  4. The trailer's rear wheels following a path inside the front wheels' path Correct answer.

Explanation

Off-tracking is the difference between the path of the front wheels and the path of the trailer's rear wheels. The rear wheels track inside the turn, which is why extra room is needed for both left and right turns. It is not related to brake timing, steering return, or highway sway.

Question 36Shifting, Backing, and Turning

You are driving a tractor-trailer and need to change lanes on a highway. What is the correct sequence?

  1. Signal, check mirrors and blind spot, then move smoothly when clear Correct answer.
  2. Honk, signal, and move without checking
  3. Signal and move at the same time to save time
  4. Check mirrors, signal, and move immediately

Explanation

A lane change in a large vehicle requires signaling, checking both mirrors and the blind spot, and then moving smoothly only when the lane is clear. Moving immediately or skipping the blind-spot check can cause a collision with a vehicle the mirrors do not show. Honking does not make a lane change safe.

Question 37Shifting, Backing, and Turning

Why should you avoid backing a tractor-trailer when you can turn around or drive around instead?

  1. Backing is the most dangerous maneuver because of blind spots and limited visibility Correct answer.
  2. Backing is faster than turning around
  3. Backing is required by law at every intersection
  4. Backing uses less fuel than driving forward

Explanation

Backing a large combination vehicle is among the most dangerous maneuvers because of extensive blind spots and the difficulty of controlling the trailer. Whenever possible, plan your route to avoid needing to back up. Backing is not faster, more efficient, or legally required at intersections.

Question 38Shifting, Backing, and Turning

A driver is turning a tractor-trailer left at an intersection and the trailer's rear wheels are tracking toward the curb on the left. What should the driver have done differently?

  1. Braked hard during the turn
  2. Accelerated through the turn
  3. Started the turn from a tighter position to the right
  4. Started the turn from a wider position to the right Correct answer.

Explanation

On a left turn, off-tracking pulls the trailer toward the inside of the turn. Starting from a wider position to the right gives the trailer room to track without hitting the left curb. A tighter start, acceleration, or hard braking would not fix the tracking problem.

Question 39Shifting, Backing, and Turning

When making a right turn in a tractor-trailer, which mirror should you watch most closely as the trailer follows through the turn?

  1. The left mirror only
  2. The interior rearview mirror
  3. The right mirror, to confirm the trailer clears the curb and corner Correct answer.
  4. The mirror on the trailer's rear door

Explanation

During a right turn the trailer cuts toward the right curb, so the right mirror shows whether the trailer is clearing the corner and any pedestrians or objects. The left mirror is less useful for this check, and a tractor-trailer typically has no interior rearview mirror.

Question 40Shifting, Backing, and Turning

You are backing a tractor-trailer and the trailer begins to jackknife. What is the safest immediate response?

  1. Stop, pull forward to straighten out, and restart the maneuver Correct answer.
  2. Turn the wheel sharply the opposite way while continuing to back
  3. Accelerate to straighten the trailer
  4. Continue backing slowly to work it out

Explanation

A jackknife means the angle between the cab and trailer has become too sharp. The safest response is to stop, pull forward to straighten the combination, and restart the backing maneuver. Accelerating, sharp counter-steering while backing, or continuing to back worsens the angle.

Question 41Shifting, Backing, and Turning

A driver must turn a 53-foot trailer right onto a street with a narrow entrance. Which combination of actions best completes the turn safely?

  1. Swing wide left, slow down, check the right mirror, and turn gradually Correct answer.
  2. Turn sharply from the right lane at normal speed
  3. Back up if the trailer nears the curb and then turn sharply
  4. Start the turn from the left lane to gain room

Explanation

A long trailer needs a wide left swing to keep the rear wheels off the right curb. Slowing down, checking the right mirror, and turning gradually keeps the trailer tracking correctly and gives time to react. Sharp turns, turning from the left lane, or backing during the turn increase risk.

Question 42Shifting, Backing, and Turning

Why can a tractor-trailer's blind spot be larger on the right side than on the left, and what does this mean for lane changes to the right?

  1. The driver sits on the left, so the right side has a larger blind area requiring a careful head check and mirror use Correct answer.
  2. The right mirror is smaller, so right lane changes need no extra check
  3. Right lane changes are illegal for tractor-trailers
  4. The trailer blocks the right mirror, making it useless

Explanation

Because the driver sits on the left, the right side of a tractor-trailer has a larger blind area than the left. Before a right lane change, the driver must use the right mirror carefully and make a head check to confirm the lane is clear. The right mirror is not useless, and right lane changes are legal when safe.

Question 43Shifting, Backing, and Turning

A driver is backing a tractor-trailer around a corner into a narrow alley. The trailer must swing wide to clear a building on the left. Which statement best describes the correct technique?

  1. Back straight in, then pivot the trailer with sharp wheel movements
  2. Back quickly before the trailer drifts
  3. Use the left mirror only and ignore the right side
  4. Set up the approach so the trailer enters at the correct angle, then make small corrections with the mirrors and a spotter Correct answer.

Explanation

Backing around a corner requires a planned setup so the trailer enters the alley at the right angle. After that, small corrections guided by both mirrors and a spotter keep the trailer clear of the building. Sharp pivots, speed, or watching only one side invite contact with structures.

Question 44Shifting, Backing, and Turning

When turning a tractor-trailer, why is it important to check both mirrors throughout the entire turn rather than only at the start?

  1. Regulations require a mirror check every five seconds
  2. The trailer's path changes continuously, and hazards can appear mid-turn Correct answer.
  3. The trailer brakes only work when the mirrors are checked
  4. The mirrors fog up during turns

Explanation

As the combination moves through a turn, the trailer's path relative to the curb, lane lines, and other traffic changes continuously. Checking both mirrors throughout the turn lets the driver catch a drifting trailer or a pedestrian entering the path. Mirrors do not affect brake function, and there is no five-second rule.

Question 45Seeing Hazards and Space Management

You are driving a tractor-trailer on a two-lane road and see a school bus stopped ahead with its red lights flashing. What does this signal require you to do?

  1. Sound your horn and proceed if no children are visible
  2. Stop only if the bus is in your lane of travel
  3. Slow to 20 mph and pass with caution on the left
  4. Stop and remain stopped until the red lights are turned off Correct answer.

Explanation

Flashing red lights on a school bus mean the bus is loading or unloading children, and traffic in both directions must stop until the lights stop flashing. Passing a stopped school bus with red lights operating is a serious violation with heavy penalties.

Question 46Seeing Hazards and Space Management

In heavy rain your steering suddenly feels light and the vehicle drifts without responding. What is the correct first response?

  1. Brake firmly to slow the wheels quickly
  2. Accelerate to push water out from under the tires
  3. Take your foot off the accelerator and avoid braking hard Correct answer.
  4. Steer sharply toward the shoulder to regain grip

Explanation

Light steering and drifting in rain indicate hydroplaning, where the tires ride on a film of water. Easing off the accelerator lets the vehicle slow gradually so the tires can regain contact with the pavement, and hard braking or sharp steering can trigger a skid.

Question 47Seeing Hazards and Space Management

What is the recommended minimum following distance for a CMV traveling below 40 mph in good conditions?

  1. Four seconds
  2. One second
  3. Two seconds Correct answer.
  4. Six seconds

Explanation

The general rule is at least one second for each 10 feet of vehicle length at speeds under 40 mph, which works out to about four seconds for a 40-foot vehicle. For speeds above 40 mph, add one extra second.

Question 48Seeing Hazards and Space Management

You are approaching a stale green light at an intersection. Which action best manages the hazard?

  1. Accelerate to clear the intersection before it turns red
  2. Maintain speed and watch for the light to change
  3. Cover the brake and prepare to stop if it changes Correct answer.
  4. Shift attention to the cross traffic signal

Explanation

A stale green light may change at any moment, so the driver should anticipate the change by covering the brake and being ready to stop. This keeps stopping distance available and avoids a rushed decision at the stop line.

Question 49Seeing Hazards and Space Management

When must you turn on your headlights while driving a CMV?

  1. When visibility is reduced or from sunset to sunrise Correct answer.
  2. Only during precipitation or fog
  3. Only when other vehicles are present
  4. Only between sunset and sunrise

Explanation

Headlights are required from sunset to sunrise and whenever conditions such as fog, rain, or smoke reduce visibility enough that you cannot clearly see persons or vehicles at a distance of 500 feet. They also make your vehicle easier for others to see.

Question 50Seeing Hazards and Space Management

What is the purpose of checking your mirrors regularly while driving?

  1. To monitor traffic and hazards around and behind the vehicle Correct answer.
  2. To decide when to shift gears
  3. To estimate the weight of the load behind you
  4. To confirm that your trailer lights are working

Explanation

Regular mirror checks keep you aware of vehicles in your blind spots and of traffic approaching from behind, which supports safe lane changes and braking decisions. Mirrors are a core part of scanning for hazards around the vehicle.