I85PREP
⌘ K
MA CDL General Knowledge study materials
MA CDL General Knowledge study resources

MA CDL General Knowledge practice questions

One question at a time. Build your MA CDL General Knowledge understanding.

First 50 of 200 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Vehicle Inspection and Basic Control

During a pre-trip inspection of a commercial vehicle, you check the slack adjusters on the service brakes. What are you primarily verifying?

  1. That the air compressor is building pressure at the proper rate
  2. That the brake linings are the correct friction rating
  3. That the brake chambers are the correct size for the axle
  4. That the push rod travel stays within the adjustment limit for that chamber type Correct answer.

Explanation

Slack adjuster inspection focuses on push rod travel: an over-stroked rod means the brakes are out of adjustment and stopping power is reduced. The rod travel limit depends on the chamber size and type, so you compare the measured travel against that limit rather than guessing.

Question 2Vehicle Inspection and Basic Control

You are performing the air brake leakage test on a combination vehicle with the engine off and the system fully charged. Which result indicates a problem that must be corrected before driving?

  1. The low pressure warning buzzer sounds when pressure falls below the warning threshold
  2. The pressure loss in one minute exceeds the limit allowed for your vehicle's system Correct answer.
  3. The pressure gauge reads the same on both the primary and secondary needles
  4. The air pressure drops slightly and then holds steady after the initial application

Explanation

A static leakage test compares the pressure drop over a set time against the maximum allowed for the system. Exceeding that limit means air is escaping faster than the system can tolerate, so the vehicle is not safe to operate until the leak is repaired.

Question 3Vehicle Inspection and Basic Control

When you check the engine compartment during a pre-trip inspection, which condition requires the vehicle to be placed out of service until corrected?

  1. The battery hold-down bracket is snug and free of corrosion
  2. A power steering hose is chafed and seeping fluid Correct answer.
  3. The oil dipstick shows the level at the full mark after sitting
  4. The coolant reservoir is at the low mark when the engine is cold

Explanation

A chafed, leaking power steering hose can fail suddenly and cause loss of steering assist, so it is a safety defect that must be repaired before operation. Fluid levels and secure, corrosion-free battery mounting are normal findings.

Question 4Vehicle Inspection and Basic Control

You are checking tire condition on a tractor-trailer during a walk-around inspection. Which finding must be corrected before the vehicle is dispatched?

  1. The valve stem cap is missing on an inner dual
  2. Tires on the same axle show slightly different wear patterns
  3. Tread depth on a steer tire is above the minimum but uneven across the tread
  4. A sidewall has a cut deep enough to expose the cord body Correct answer.

Explanation

Any cut or damage that reaches the cord body compromises the tire's structure and can lead to a blowout, so the tire must be replaced. Uneven wear, minor pressure differences, and a missing valve cap are maintenance items rather than immediate out-of-service defects.

Question 5Vehicle Inspection and Basic Control

During the pre-trip inspection, you check the coupling system on a tractor-trailer. Which check confirms the fifth wheel is properly locked?

  1. Tug test: with the trailer brakes set, gently pull forward and confirm the tractor does not separate Correct answer.
  2. Height check: the trailer apron sits above the fifth wheel plate
  3. Visual check: the release handle is pulled out and hanging free
  4. Air check: the trailer air supply line shows no leaks at the gladhand

Explanation

The tug test verifies that the kingpin is captured by the locking jaws: with the trailer brakes applied, a gentle pull should not separate the tractor from the trailer. You then visually confirm the jaws are closed around the kingpin and the release handle is in the locked position.

Question 6Vehicle Inspection and Basic Control

You are inspecting the lighting system before a night trip. Which condition is a defect that must be repaired before departure?

  1. The four-way flashers operate on all corners
  2. A turn signal on the trailer flashes but a rear clearance lamp on the same side is dark Correct answer.
  3. The clearance lamps illuminate with the headlamp switch
  4. The brake lights illuminate when the service brake is applied

Explanation

Every required lamp must function, so a dark clearance lamp is a defect even though the turn signal works. Required lighting failures reduce the vehicle's visibility and can lead to citations, so they must be fixed before the trip.

Question 7Vehicle Inspection and Basic Control

When you perform the engine start and gauge check, which observation indicates a problem with the charging system?

  1. The ammeter shows a slight discharge with all accessories on at idle
  2. The voltmeter stays below normal charging range while engine speed is raised Correct answer.
  3. The voltmeter reads slightly above battery voltage with the engine running
  4. The oil pressure gauge rises within a few seconds of starting

Explanation

A charging system should bring the voltmeter into its normal range once the engine runs above idle. If voltage stays low at increased engine speed, the alternator or its circuit is likely failing and the batteries will not stay charged.

Question 8Vehicle Inspection and Basic Control

You are inspecting the exhaust system on a diesel-powered commercial vehicle. Which condition requires repair before operation?

  1. The muffler shows surface rust but no perforation
  2. A hanger is loose and the pipe contacts the frame Correct answer.
  3. The tailpipe extends past the rear of the cab
  4. The exhaust manifold bolts are tight and dry

Explanation

A loose hanger allowing metal-to-metal contact can damage the pipe and let exhaust leak into the cab. Exhaust leaks are a carbon monoxide hazard, so the mounting must be secured before driving.

Question 9Vehicle Inspection and Basic Control

During a pre-trip inspection, you check the steering system. Which condition is an out-of-service defect?

  1. A tie rod end has noticeable looseness when you rock the component Correct answer.
  2. The steering gear box is securely mounted
  3. The steering wheel has slight free play within the manufacturer's limit
  4. The power steering fluid is at the full mark

Explanation

Looseness in a tie rod end means the steering linkage can separate or wander, which is a serious safety defect. Free play within the manufacturer's limit, proper fluid level, and a secure gear box are all normal findings.

Question 10Vehicle Inspection and Basic Control

You are inspecting the suspension on a tractor during a walk-around. Which finding must be corrected before the vehicle is placed in service?

  1. The shock absorbers show minor oil film near the seal
  2. The torque arm bushings are intact and free of play
  3. A leaf spring has light surface rust
  4. An air bag has a small crack in the rubber and leaks when pressurized Correct answer.

Explanation

A leaking air bag cannot maintain ride height or load support and can fail completely, so it must be replaced. Surface rust, minor oil film, and intact bushings are not out-of-service conditions.

Question 11Vehicle Inspection and Basic Control

Before moving a combination vehicle, you must verify the trailer air supply and service lines are properly connected. What does a properly connected trailer air supply line provide?

  1. It supplies air to the trailer's suspension only
  2. It powers the trailer's electrical marker lamps
  3. It charges the trailer's air tanks and releases the spring brakes when pressure is adequate Correct answer.
  4. It controls the trailer service brakes when you press the brake pedal

Explanation

The supply line (emergency line) charges the trailer's air tanks and signals the trailer spring brakes to release once pressure is sufficient. The service line, by contrast, carries the application signal when the brake pedal is pressed.

Question 12Vehicle Inspection and Basic Control

You are checking the electrical cable and air lines between the tractor and trailer. Which condition is a defect that must be fixed before departure?

  1. The gladhands are sealed with new rubber gaskets
  2. The lines have enough slack to turn without binding
  3. The electrical cable is supported so it does not drag on the ground
  4. The air lines are crossed so the supply line is connected to the service coupler Correct answer.

Explanation

Crossed air lines mean the trailer brakes will not function as designed and can stay applied or fail to release, so the lines must be reconnected correctly. Proper support, good gaskets, and adequate slack are all correct conditions.

Question 13Vehicle Inspection and Basic Control

During the pre-trip inspection, you check the trailer landing gear and rear frame. Which condition is an out-of-service defect?

  1. The rear impact guard is securely attached
  2. A crack is visible in the frame rail near the suspension hanger Correct answer.
  3. The mud flaps are present and hang straight
  4. The landing gear crank turns freely and the legs are fully raised

Explanation

A crack in a frame rail compromises the structural integrity of the trailer and can lead to catastrophic failure, so the vehicle must be removed from service. Freely turning landing gear, proper mud flaps, and a secure impact guard are all normal.

Question 14Vehicle Inspection and Basic Control

You are checking the brake system on a vehicle with hydraulic brakes. Which condition indicates a problem that must be repaired before driving?

  1. The parking brake holds the vehicle on a slight incline
  2. The brake pedal feels firm and holds when pressed
  3. The pedal slowly sinks toward the floor while held under steady pressure Correct answer.
  4. The brake fluid reservoir is at the full line

Explanation

A pedal that sinks under steady pressure indicates a leak in the hydraulic system or a failing master cylinder, which can lead to total brake loss. A firm pedal, proper fluid level, and a working parking brake are normal.

Question 15Vehicle Inspection and Basic Control

You are performing the air brake test and check the low pressure warning. At what point must the warning device activate?

  1. Only when the parking brake is applied
  2. Before the pressure in the system drops below the minimum safe operating level Correct answer.
  3. When the compressor governor cuts in
  4. After the spring brakes have fully engaged

Explanation

The low pressure warning must activate before air pressure falls below the minimum safe level so the driver has time to stop safely. If the warning does not sound at the specified pressure, the vehicle must be repaired before operation.

Question 16Vehicle Inspection and Basic Control

During the pre-trip inspection, you check the spring brake (emergency) system. Which result indicates the system is working correctly?

  1. The spring brakes apply only when the parking brake valve is pulled
  2. The spring brakes release when air pressure is lost
  3. The spring brakes apply automatically, typically between 20 and 45 psi, after the low air warning activates Correct answer.
  4. The spring brakes hold the vehicle only on level ground

Explanation

Spring brakes are designed to apply automatically when air pressure falls sufficiently, typically between 20 and 45 psi. The low air pressure warning should activate earlier. This automatic application provides a fail-safe; pressure loss must not release the spring brakes, and they should hold the vehicle on grades as well as level ground.

Question 17Vehicle Inspection and Basic Control

You are checking the vehicle's mirrors and windshield before departure. Which condition must be corrected before driving?

  1. The mirrors are adjusted to show the sides and rear of the vehicle
  2. The wipers clear the windshield in a sweeping motion
  3. The windshield has a crack in the driver's line of sight Correct answer.
  4. The washer fluid reservoir is full

Explanation

A crack in the driver's line of sight obstructs vision and is a defect that must be repaired. Properly adjusted mirrors, working wipers, and a full washer reservoir are all normal.

Question 18Vehicle Inspection and Basic Control

You are checking the horn and emergency equipment before a trip. Which item is required emergency equipment for a commercial vehicle?

  1. An extra set of license plate bolts
  2. A portable air compressor
  3. A fire extinguisher rated for the vehicle's class Correct answer.
  4. A spare set of windshield wiper blades

Explanation

Commercial vehicles must carry a properly rated and charged fire extinguisher, along with other required items such as warning triangles. Spare wiper blades, a portable compressor, and extra bolts are not required emergency equipment.

Question 19Vehicle Inspection and Basic Control

You are inspecting the cargo securement on a flatbed trailer before departure. Which condition requires correction?

  1. The load is marked with flags at the rear overhang
  2. A tie-down strap has a frayed section with broken fibers Correct answer.
  3. The cargo is centered over the trailer axles
  4. The cargo is covered with a tarp that is securely fastened

Explanation

A frayed strap with broken fibers has reduced strength and can fail under load, so it must be replaced. A secure tarp, centered cargo, and proper flags are all correct securement practices.

Question 20Vehicle Inspection and Basic Control

Before backing a tractor-trailer, you complete a pre-trip inspection and check the backup alarm and lights. Which condition is a defect?

  1. The backup alarm sounds continuously while driving forward Correct answer.
  2. The backup alarm sounds when reverse is engaged
  3. The rear clearance lamps illuminate with the headlamps
  4. The backup lights illuminate when reverse is engaged

Explanation

A backup alarm that sounds while driving forward is a malfunction that can confuse other drivers and indicates a wiring or switch fault. Backup lights and alarm operating in reverse, and clearance lamps working with the headlamps, are correct.

Question 21Vehicle Inspection and Basic Control

You are performing a pre-trip inspection on a vehicle equipped with an anti-lock braking system (ABS). What should you check regarding the ABS?

  1. That the ABS pump runs continuously at idle
  2. That the ABS is disabled when the parking brake is set
  3. That the ABS warning lamp remains lit while driving
  4. That the ABS warning lamp comes on at start-up and then goes out Correct answer.

Explanation

The ABS lamp should illuminate briefly during start-up as a self-test and then extinguish; if it stays on, the system has a fault. A lamp that remains lit or a pump that runs continuously indicates a problem requiring repair.

Question 22Vehicle Inspection and Basic Control

During a pre-trip inspection, you check the air compressor and governor. Which observation indicates the governor is working correctly?

  1. The compressor cuts out at the maximum pressure and cuts back in at a lower pressure Correct answer.
  2. The pressure gauge climbs without ever reaching cut-out
  3. The compressor runs continuously regardless of system pressure
  4. The safety valve releases air whenever the compressor runs

Explanation

The governor cycles the compressor off at the cut-out pressure and back on at the cut-in pressure, keeping system pressure within a safe range. Continuous running, constant safety valve release, or pressure that never reaches cut-out all indicate governor or compressor faults.

Question 23Vehicle Inspection and Basic Control

You are checking the wheels and rims during the walk-around inspection. Which condition is an out-of-service defect?

  1. A wheel has a crack extending from a lug hole to the rim edge Correct answer.
  2. The lug nuts are rusted but tight
  3. The wheel is dirty with road grime
  4. The valve stem is straight and uncapped

Explanation

A crack radiating from a lug hole compromises the wheel and can cause it to fail, so the vehicle must be taken out of service. Rusted but tight lug nuts, road grime, and an uncapped valve stem are not structural defects.

Question 24Vehicle Inspection and Basic Control

After completing a pre-trip inspection, you start the engine and check the gauges. Which reading requires you to shut down and investigate before driving?

  1. Coolant temperature climbs into the normal range
  2. The voltmeter reads in the normal charging range
  3. Oil pressure rises to normal within a few seconds
  4. Oil pressure remains at zero after the engine starts Correct answer.

Explanation

Zero oil pressure after start-up means the engine is not being lubricated and can be destroyed within seconds, so you must shut down immediately. Normal oil pressure, coolant temperature, and charging voltage are all expected readings.

Question 25Vehicle Inspection and Basic Control

You are inspecting the coupling system and notice the trailer apron rests below the top of the fifth wheel plate after coupling. What does this indicate?

  1. The fifth wheel is locked and ready for the road
  2. The trailer may not be fully seated, so you must not drive until it is corrected Correct answer.
  3. The trailer brakes are properly released
  4. The trailer is properly seated on the fifth wheel

Explanation

When the trailer is properly coupled, the apron sits flat against the top of the fifth wheel plate. If the apron is below the plate, the kingpin may not be fully captured, so you must not move the vehicle until the coupling is corrected.

Question 26Vehicle Inspection and Basic Control

During a pre-trip inspection you check the tires on a heavy commercial vehicle. Which tread condition means the tire is out of service and must be replaced before the vehicle is driven?

  1. A drive tire with tread depth of 6/32 inch across the tread
  2. A trailer tire with tread depth of 3/32 inch at the center
  3. A front steer tire with tread depth of 5/32 inch on the outer edge
  4. A front steer tire with tread depth below 4/32 inch in any major groove Correct answer.

Explanation

Federal out-of-service criteria require at least 4/32 inch of tread depth in every major groove on front steer tires, while other tires need at least 2/32 inch. A steer tire below 4/32 inch fails that standard and cannot be used until replaced. Depths at or above the minimum in the correct position are acceptable.

Question 27Vehicle Inspection and Basic Control

You are about to move a loaded commercial vehicle and must check the service brakes for a leak. With the engine running, the system fully charged, and the brake pedal held down, which result indicates a brake system defect?

  1. Air pressure rises slightly and then stabilizes while the pedal is held.
  2. Air pressure drops slowly and then holds steady at the lower reading.
  3. Air pressure drops more than 3 psi in one minute with the pedal held down. Correct answer.
  4. Air pressure remains unchanged for the full minute the pedal is held.

Explanation

For a combination vehicle, the air brake leak test allows no more than 3 psi loss in one minute with the pedal fully applied and the system charged. A drop greater than 3 psi signals a leak that must be found and repaired. A steady or stable reading within the limit is normal.

Question 28Vehicle Inspection and Basic Control

While driving a tractor-trailer on a straight, level road, you notice the vehicle pulls steadily to the left when you are not steering. Which condition most likely explains this behavior?

  1. The engine idle speed is set slightly too high.
  2. The trailer is loaded with the heavier cargo on the right side.
  3. The wheel alignment is incorrect or a front tire is underinflated. Correct answer.
  4. The front tires are overinflated on both sides equally.

Explanation

Steady pull to one side on a level road usually points to misalignment or unequal front tire pressure, which makes the steering lead toward the low or dragged side. This should be corrected before the trip, since it affects steering control and tire wear. Cargo imbalance and idle speed do not cause consistent steering pull.

Question 29Vehicle Inspection and Basic Control

You must make a tight right turn in a tractor-trailer at an intersection. Which technique keeps the trailer from climbing the curb or striking objects on the right?

  1. Swing wide to the left before turning, then complete the turn in the rightmost lane. Correct answer.
  2. Begin the turn from the far left lane and cut sharply across the corner.
  3. Turn from the right lane while keeping the tractor close to the right curb.
  4. Brake hard in the turn to slow the trailer and tighten the path.

Explanation

Because the trailer cuts the corner, a right turn requires swinging wide to the left first and then finishing the turn in the correct lane without crossing into oncoming traffic. This keeps the rear wheels of the trailer clear of the curb and nearby objects. Turning tight from the right lane or braking mid-turn does not solve the off-tracking problem.

Question 30Vehicle Inspection and Basic Control

You are driving a loaded combination vehicle down a long, steep downgrade and want to control speed without overheating the brakes. Which approach best applies the rule for safe downgrade control?

  1. Pump the brakes firmly and repeatedly to keep the drums cool throughout the descent.
  2. Keep the transmission in a high gear and apply steady, light brake pressure the entire way down.
  3. Descend in neutral to let the engine idle and rely on the brakes to hold a constant speed.
  4. Shift to a lower gear before the descent and use the brakes only enough to keep engine rpm in the safe range. Correct answer.

Explanation

The safe rule is to select a gear low enough that engine braking holds the vehicle near the desired speed, using the brakes briefly to keep rpm in the proper range. This prevents the continuous heat buildup that causes brake fade. Coasting in neutral or riding the brakes removes engine braking and overheats the system.

Question 31Shifting, Backing, and Turning

Before shifting a manual transmission from a higher gear into a lower gear while moving, what should the driver do to protect the transmission and keep the vehicle stable?

  1. Hold the clutch pedal down and coast to a stop first
  2. Skip directly to the lowest gear available
  3. Shift down at the highest safe speed for the lower gear
  4. Match engine speed to the lower gear before releasing the clutch Correct answer.

Explanation

Downshifting requires the engine speed to rise to match the lower gear's ratio. Matching engine rpm before the clutch engages prevents driveline shock and keeps the drive wheels from breaking traction. Coasting with the clutch disengaged removes engine braking and control.

Question 32Shifting, Backing, and Turning

When backing a tractor-trailer, in which direction should you turn the steering wheel to make the rear of the trailer move toward the driver's side (left)?

  1. Turn the wheel left, then immediately right
  2. Turn the wheel to the right
  3. Turn the wheel to the left Correct answer.
  4. Hold the wheel straight and let the trailer drift

Explanation

When backing, the trailer pivots opposite the tractor's steering input. Turning the wheel left swings the tractor's rear right and pushes the trailer's rear to the left, toward the driver's side. Steering must then be corrected to keep the combination in line.

Question 33Shifting, Backing, and Turning

What is the correct hand position for holding the steering wheel during normal driving?

  1. One hand at the bottom center
  2. Left hand at 9 o'clock and right hand at 3 o'clock Correct answer.
  3. Both hands at the top of the wheel
  4. Both hands crossed at the bottom

Explanation

Placing the hands at 9 and 3 o'clock gives the best control and keeps the arms clear of an inflating airbag. This position also allows a full turn without crossing the arms. Hands at the top of the wheel can be struck by the airbag or trapped during a rapid turn.

Question 34Shifting, Backing, and Turning

When must a driver use turn signals when making a turn or lane change?

  1. Only when turning at an intersection with a traffic light
  2. Continuously for at least the last 100 feet before the turn Correct answer.
  3. Only when a police officer is directing traffic
  4. Only when other vehicles are visible nearby

Explanation

Signals must be given continuously for a set distance before turning or changing lanes so other road users have warning. The distance varies by state, but a commonly required minimum is 100 feet before the turn. Signaling only when traffic is visible defeats the purpose of warning others.

Question 35Shifting, Backing, and Turning

A commercial driver is backing a straight truck into a loading dock. Which practice best reduces the risk of a backing collision?

  1. Rely on the backup alarm to clear the area
  2. Use a helper or spotter and stop if you lose sight of them Correct answer.
  3. Back slowly while watching only the left mirror
  4. Back quickly to minimize time in the blind spot

Explanation

A spotter can see areas hidden from the driver's mirrors and can stop traffic or pedestrians. If the driver loses sight of the spotter, the driver must stop immediately because the spotter may be in a blind area. Backup alarms help but do not replace direct observation.

Question 36Shifting, Backing, and Turning

When approaching a right turn in a large combination vehicle, where should the vehicle be positioned before the turn?

  1. In the center of the road
  2. In the far left lane to widen the arc
  3. Straddling the lane line to block traffic
  4. Close to the right edge of the road Correct answer.

Explanation

A right turn should begin from as close to the right edge as practical so the trailer does not swing over the curb or into adjacent lanes. The driver then turns wide enough to keep the rear wheels clear of the corner. Starting from the left or center increases off-tracking hazards.

Question 37Shifting, Backing, and Turning

Why does a tractor-trailer's rear wheels track inside the path of the front wheels during a turn?

  1. The trailer has a shorter wheelbase than the tractor
  2. The rear wheels follow a tighter radius than the front wheels Correct answer.
  3. The trailer brakes apply unevenly in turns
  4. The steering axle is located behind the drive axle

Explanation

Off-tracking occurs because the rear axles cut a smaller radius than the steering axle. The longer the wheelbase and the sharper the turn, the greater the distance the rear wheels track inside the front path. Drivers must allow for this when turning near curbs, poles, and other vehicles.

Question 38Shifting, Backing, and Turning

While backing a trailer, the trailer begins to turn too sharply and jackknife. What is the best corrective action?

  1. Apply the trailer brakes only and hold the wheel
  2. Stop, pull forward to straighten the combination, then resume backing Correct answer.
  3. Accelerate to pull the trailer straight
  4. Continue backing and steer harder into the turn

Explanation

Once a trailer approaches a jackknife angle, continuing to back worsens it. The safe correction is to stop, pull forward until the tractor and trailer are aligned, and then restart the backing maneuver with smaller steering inputs. Small corrections early prevent the angle from growing.

Question 39Shifting, Backing, and Turning

A driver must back across a sidewalk into a street. What is the safest procedure?

  1. Sound the horn once and back without stopping
  2. Back out quickly so pedestrians have less time in the path
  3. Use a spotter, check both directions, and back only when the path is clear Correct answer.
  4. Back only at night when pedestrians are less likely

Explanation

Backing across a sidewalk puts pedestrians and cross traffic in the vehicle's blind area. A spotter, a full check of both directions, and backing only when the path is clear reduce the risk. Speed or darkness do not make the maneuver safer.

Question 40Shifting, Backing, and Turning

When making a left turn with a long combination vehicle, what should the driver do to avoid the trailer crossing the curb or oncoming lane?

  1. Keep the tractor in the left lane and ignore the trailer path
  2. Begin the turn early and accelerate through it
  3. Swing wide to the right before turning left, then complete the turn in the proper lane Correct answer.
  4. Turn from the right lane and cut the corner sharply

Explanation

A left turn with a long combination requires the driver to swing slightly right before turning so the trailer clears the corner. The driver must then complete the turn into the correct lane without cutting the corner. Cutting the corner causes the trailer to track over the curb or into oncoming traffic.

Question 41Shifting, Backing, and Turning

What does a driver do with the clutch when stopping a manual-transmission commercial vehicle?

  1. Shift to neutral and release the clutch while still moving fast
  2. Depress the clutch just before the engine reaches idle speed to prevent stalling Correct answer.
  3. Keep the clutch engaged until the vehicle is fully stopped and the engine stalls
  4. Release the clutch immediately after braking begins

Explanation

As the vehicle slows, the clutch must be depressed before engine speed drops to the stalling point. This disconnects the engine from the driveline so the vehicle can stop smoothly without stalling. Releasing the clutch too early causes a stall or lurch.

Question 42Shifting, Backing, and Turning

A driver is backing a trailer and cannot see the rear of the trailer in either mirror. What should the driver do?

  1. Stop and get out to check the area, or use a spotter Correct answer.
  2. Turn the wheel to swing the trailer into view
  3. Continue slowly and rely on the backup alarm
  4. Speed up to clear the area quickly

Explanation

If the rear of the trailer cannot be seen, the driver has no way to know whether the path is clear. The driver should stop, then either check the area personally or use a spotter before continuing. Continuing to back while blind to the rear risks a collision.

Question 43Shifting, Backing, and Turning

Which statement correctly describes the effect of vehicle speed on the radius of a turn?

  1. Speed has no effect on the turn radius
  2. Turn radius depends only on tire pressure
  3. Higher speed increases the radius the vehicle actually travels Correct answer.
  4. Higher speed decreases the radius the vehicle actually travels

Explanation

At higher speed, centrifugal force pushes the vehicle outward, so it travels a wider arc than the steering angle alone would produce. Drivers must slow before entering a turn to stay within the intended lane. Tire pressure affects grip but does not set the turn radius.

Question 44Shifting, Backing, and Turning

When shifting a manual transmission while going up a steep grade, what is the main reason to downshift before the engine loses power?

  1. To reduce fuel consumption on the grade
  2. To increase the load on the trailer brakes
  3. To keep engine rpm in the power band and avoid stalling Correct answer.
  4. To make the exhaust brake more effective

Explanation

On a steep grade, engine rpm falls as the load increases. Downshifting before the engine lugs keeps rpm in the range where the engine produces enough power to climb. Waiting until the engine loses power can force a stalled or missed shift.

Question 45Shifting, Backing, and Turning

A driver is turning right at an intersection and a cyclist is in the bike lane to the right. What should the driver do?

  1. Move into the bike lane to block the cyclist
  2. Turn right ahead of the cyclist if the light is green
  3. Wait for the cyclist to clear the intersection before turning Correct answer.
  4. Sound the horn and turn anyway

Explanation

A right-turning vehicle must not cut across a cyclist traveling straight in the bike lane. The driver should yield and wait until the cyclist has cleared the path before completing the turn. Turning ahead of the cyclist risks a collision.

Question 46Shifting, Backing, and Turning

What is the correct sequence for a driver preparing to back a combination vehicle into a tight space?

  1. Get out and check the area, position the vehicle, use a spotter, and back slowly Correct answer.
  2. Turn the wheel fully before moving and hold it
  3. Set the parking brake, back, then check mirrors
  4. Rely on the mirrors alone and back at normal speed

Explanation

Backing into a tight space requires the driver to check the area first, position the tractor to allow a good approach, and use a spotter. Backing slowly with frequent checks keeps the combination under control. Mirrors alone do not cover all blind areas.

Question 47Shifting, Backing, and Turning

A driver is descending a long grade and wants to use engine braking. Which technique is correct for a manual transmission?

  1. Keep the clutch depressed to allow free rolling
  2. Downshift only after the brakes begin to fade
  3. Shift to neutral and rely on the service brakes
  4. Select a lower gear before the descent and let engine braking hold speed Correct answer.

Explanation

Selecting a lower gear before the descent allows engine braking to control speed and reduces reliance on the service brakes. This prevents brake fade on long grades. Coasting in neutral or with the clutch depressed removes engine braking and is unsafe.

Question 48Shifting, Backing, and Turning

What hazard is created when a long combination vehicle makes a right turn from the left lane?

  1. The rear wheels will track outside the front wheels
  2. The tractor will understeer and drift left
  3. The trailer may swing over the curb or into the right lane Correct answer.
  4. The trailer brakes will lock automatically

Explanation

Starting a right turn from the left lane forces the trailer to travel a wider arc and swing over the curb or into the right lane. The correct approach is to begin from the right edge and turn wide enough to keep the rear wheels clear. Off-tracking, not oversteer, is the primary hazard.

Question 49Shifting, Backing, and Turning

A driver must make a tight left turn where the trailer could strike a pole on the inside of the corner. What is the best approach?

  1. Swing wide to the right before the turn and watch the trailer's inside path Correct answer.
  2. Turn from the right lane and cut close to the pole
  3. Accelerate through the turn to clear the pole quickly
  4. Ignore the pole and rely on the trailer's length

Explanation

Swinging wide before a left turn increases clearance for the trailer's inside path around the corner. The driver should watch the trailer's rear wheels and mirror to confirm clearance. Cutting close or accelerating through the turn increases the risk of striking the pole.

Question 50Shifting, Backing, and Turning

A driver in a manual-transmission tractor-trailer is approaching a curve and wants to slow the vehicle using the transmission rather than the brakes alone. What is the recommended procedure for downshifting before entering the curve?

  1. Shift directly from the top gear to the lowest usable gear to obtain maximum engine braking
  2. Downshift while still at highway speed so the engine compression slows the vehicle through the curve
  3. Hold the clutch pedal down through the curve and release it after the curve to select a lower gear
  4. Slow to the proper speed first, then downshift one gear at a time while keeping engine speed matched to road speed Correct answer.

Explanation

The safe practice is to reduce speed before the curve, then downshift one gear at a time so engine speed matches road speed and the drive wheels are not shocked. Shifting is completed before the curve so both hands are on the wheel and the vehicle is stable while turning. Selecting the right gear before the curve also keeps engine braking available without abrupt changes mid-turn.