CDL Commercial Learner's Permit (CLP) Exam — Questions and Answers

Question 1: What does it indicate if the air pressure in the brake system drops more than 3 psi per minute during a static leak test?

The compressor is working properly
This is within the normal acceptable range
There is a leak in the air system that must be repaired (Correct answer)
The pressure relief valve is functioning

Correct answer: There is a leak in the air system that must be repaired

A drop of more than 3 psi per minute in a single-vehicle system (or 4 psi in a combination) indicates an unacceptable air leak requiring repair.

Question 2: What information must appear on a hazardous materials label affixed to a package?

The shipper's name, address, and phone number only
The hazard class or division, the UN number, and a pictogram or symbol identifying the hazard (Correct answer)
The driver's CDL number and endorsement code
Only the UN identification number

Correct answer: The hazard class or division, the UN number, and a pictogram or symbol identifying the hazard

Hazmat labels must show the hazard class/division, the UN/NA number, and the hazard pictogram so that handlers can quickly identify the risk.

Question 3: What is the off-tracking difference in a long combination vehicle compared to a single unit truck?

The rear wheels follow a significantly shorter path (inside) than the front wheels when turning (Correct answer)
Off-tracking only occurs in reverse, not in forward turns
All axles follow exactly the same path in a combination vehicle
The rear wheels follow a longer path (outside) than the front wheels

Correct answer: The rear wheels follow a significantly shorter path (inside) than the front wheels when turning

Off-tracking causes the rear wheels to cut corners more severely than the front wheels, requiring drivers to allow extra space on the inside of turns.

Question 4: What should you do if the low air pressure warning activates while driving?

Switch to the secondary air system using the dashboard toggle
Continue driving but avoid hard braking
Increase speed to reach the nearest truck stop quickly
Stop the vehicle safely and as quickly as possible (Correct answer)

Correct answer: Stop the vehicle safely and as quickly as possible

When the low air pressure warning activates, you should stop the vehicle immediately and safely, as braking ability will soon be severely impaired.

Question 5: A CDL driver who is convicted of leaving the scene of an accident involving a CMV receives a minimum CDL disqualification of:

60 days
90 days
1 year (Correct answer)
3 years

Correct answer: 1 year

Leaving the scene of an accident while driving a CMV results in a one-year minimum CDL disqualification.

Question 6: What does a properly functioning air dryer do in an air brake system?

Increases air pressure to compensate for system leaks
Removes moisture and contaminants from compressed air before it reaches the tanks (Correct answer)
Cools the compressed air before it enters the brake chambers
Automatically drains the air tanks every 8 hours

Correct answer: Removes moisture and contaminants from compressed air before it reaches the tanks

An air dryer removes water vapor and contaminants from compressed air to prevent moisture buildup that could freeze lines or damage system components.

Question 7: Why is it important to check that the sliding fifth wheel is locked in position before driving?

An unlocked fifth wheel will sound the low-air warning alarm
An unlocked fifth wheel prevents proper air line connection
An unlocked fifth wheel will cause the trailer brakes to fail
An unlocked fifth wheel can slide and shift the load, affecting steering and braking (Correct answer)

Correct answer: An unlocked fifth wheel can slide and shift the load, affecting steering and braking

If the fifth wheel slides unexpectedly, weight distribution changes dramatically, causing dangerous handling and possible loss of control.

Question 8: What is 'bracing' in the context of cargo securement?

Inflating tires to maximum pressure to stabilize the load
Using extra tie-downs on the trailer frame
Attaching cargo directly to the kingpin
Rigid structures that prevent cargo from tipping or shifting (Correct answer)

Correct answer: Rigid structures that prevent cargo from tipping or shifting

Bracing uses rigid structures (such as wood dunnage or metal bars) placed against cargo to prevent it from tipping or shifting.

Question 9: Under federal law, which of these actions is prohibited for a CLP holder during supervised practice driving?

Driving during daylight hours on city streets
Practicing backing maneuvers in a private lot
Using a handheld mobile device while driving (Correct answer)
Driving on a limited-access highway with a CDL supervisor

Correct answer: Using a handheld mobile device while driving

FMCSA prohibits all CMV drivers, including CLP holders, from using handheld mobile devices while operating a commercial motor vehicle.

Question 10: A CLP holder is restricted from operating a CMV in which of the following situations?

On any road with a CDL holder present
Transporting passengers for hire without a P endorsement (Correct answer)
On a state highway with light traffic
Pulling an empty trailer on a rural road

Correct answer: Transporting passengers for hire without a P endorsement

A CLP holder cannot transport passengers for hire unless they have the P endorsement on their CLP and the accompanying CDL holder also has the P endorsement.

Question 11: What is 'brake fade' and when is it most likely to occur?

Brakes freeze in cold weather, most common in winter
Brake pedal becomes spongy due to air in lines, most common after repairs
Brakes grab suddenly, most common on wet roads
Brakes overheat and lose effectiveness, most common on long downgrades (Correct answer)

Correct answer: Brakes overheat and lose effectiveness, most common on long downgrades

Brake fade occurs when brakes overheat from excessive use, most commonly when riding the brakes on long, steep downgrades.

Question 12: What is the safest following distance for a commercial vehicle traveling at 55 mph under normal conditions?

At least 1 second for every 10 feet of vehicle length (Correct answer)
At least 3 car lengths regardless of vehicle size
At least 2 seconds for every 10 mph of speed
At least 4 seconds total behind the vehicle ahead

Correct answer: At least 1 second for every 10 feet of vehicle length

Federal CDL guidelines recommend a minimum of one second per 10 feet of vehicle length, plus one additional second if over 40 mph.

Question 13: What must a driver do before loading or unloading hazardous materials at a facility?

Set the parking brake and, if required, chock the wheels (Correct answer)
Notify the nearest fire station
Complete an ERG checklist
Obtain written permission from FMCSA

Correct answer: Set the parking brake and, if required, chock the wheels

Before loading or unloading, the driver must set the parking brake and use wheel chocks if required to prevent the vehicle from moving during the operation.

Question 14: A load of lumber is stacked 6 feet high on a flatbed. What is the main safety concern with this configuration?

The load may exceed length regulations
Lumber requires refrigeration to prevent warping
The lumber may absorb moisture
A high center of gravity increases rollover risk (Correct answer)

Correct answer: A high center of gravity increases rollover risk

A tall, high-stacked load raises the vehicle's center of gravity, significantly increasing the risk of rollover, especially during turns or sudden maneuvers.

Question 15: Smoke from a wildfire or industrial source creates driving hazards most similar to which condition?

High crosswinds
Heavy rain
Dense fog (Correct answer)
Black ice

Correct answer: Dense fog

Smoke reduces visibility in ways similar to dense fog and requires the same precautions, including low beams and reduced speed.

Question 16: On ice, stopping distances for a commercial vehicle can increase by up to how many times compared to dry pavement?

6 times
10 times (Correct answer)
2 times
4 times

Correct answer: 10 times

On ice, stopping distances can increase up to 10 times compared to dry pavement, requiring dramatically longer following distances.

Question 17: When coupling a tractor to a trailer, at what height should the trailer nose be before backing under it?

Slightly lower than the fifth wheel height so the fifth wheel rides up onto the trailer plate (Correct answer)
Height does not matter as long as the kingpin is visible
At the same height as the fifth wheel
Higher than the fifth wheel so the trailer slides down onto it

Correct answer: Slightly lower than the fifth wheel height so the fifth wheel rides up onto the trailer plate

The trailer should be slightly lower than the fifth wheel so as the tractor backs under, the fifth wheel raises and engages the kingpin properly.

Question 18: What is 'rearward amplification' in a triple combination vehicle?

The amplified signal from the rear brake sensors
The increase in engine noise toward the rear of the combination
The tendency of the last trailer to sway more violently than the first trailer during a lane change (Correct answer)
Increased braking force applied to rear axles only

Correct answer: The tendency of the last trailer to sway more violently than the first trailer during a lane change

Rearward amplification means the last trailer in a triple can sway or tip at a much higher rate than the steering inputs or first trailer movement would suggest.

Question 19: When making a right turn in a large commercial vehicle, what is the proper technique to prevent the trailer from tracking over the curb?

Turn late, after the tractor's front axle has passed the corner.
Turn as tightly as possible to minimize intersection blockage.
Increase speed slightly to help the trailer follow the tractor's path.
Swing wide to the left before initiating the turn. (Correct answer)

Correct answer: Swing wide to the left before initiating the turn.

To execute a safe right turn and prevent the trailer from hitting the curb (off-tracking), the driver must create more space. This is achieved by moving the tractor slightly to the left into the next lane before starting the turn, a technique often called a 'button hook' or 'jug handle' turn.

Question 20: What is the purpose of the air compressor governor in an air brake system?

To cut out the compressor when tank pressure reaches the maximum level and cut it in when pressure drops (Correct answer)
To regulate the speed of the air compressor motor
To control the rate at which air flows to the brake chambers
To prevent the air dryer from freezing in cold weather

Correct answer: To cut out the compressor when tank pressure reaches the maximum level and cut it in when pressure drops

The governor controls the air compressor by cutting it out when tank pressure reaches about 125 psi and cutting it back in when pressure drops to around 100 psi.

Question 21: At what angle should tie-down straps be applied relative to the trailer bed for maximum effectiveness?

At a 10-degree angle only
At a 45-degree angle when possible (Correct answer)
Perfectly vertical (90 degrees)
Perfectly horizontal (0 degrees)

Correct answer: At a 45-degree angle when possible

Tie-down straps applied at approximately 45 degrees provide the best combination of downward clamping force and horizontal restraint force.

Question 22: Under CDL regulations, a driver must notify their state licensing authority within how many days of a traffic conviction in another state?

Drivers are not required to self-report; states share data automatically
10 days
30 days (Correct answer)
60 days

Correct answer: 30 days

CDL holders must notify their home state licensing authority within 30 days of any out-of-state traffic conviction.

Question 23: What is the role of the S-cam in a drum air brake system?

It rotates to force the brake shoes outward against the brake drum when brakes are applied (Correct answer)
It prevents the brakes from locking up during hard stops
It regulates the amount of air sent to each brake chamber
It connects the air chamber push rod to the slack adjuster

Correct answer: It rotates to force the brake shoes outward against the brake drum when brakes are applied

When air pressure moves the push rod, it turns the S-cam, which pushes the brake shoes outward against the drum to create friction and slow the vehicle.

Question 24: What is the recommended method for checking the path before backing a commercial vehicle?

Turn on all four-way flashers and begin backing immediately
Ask a bystander to direct you from the front of the truck
Use only the driver-side mirror to scan the area
Get Actively Out And Look (G.O.A.L.) before and during the maneuver (Correct answer)

Correct answer: Get Actively Out And Look (G.O.A.L.) before and during the maneuver

G.O.A.L. (Get Out And Look) is the safest practice because mirrors have blind spots that walking around the vehicle eliminates.

Question 25: When following another vehicle on a highway at 55 mph, what is the minimum following distance recommended for a CMV under ideal conditions?

6 seconds (Correct answer)
4 seconds
5 seconds
7 seconds

Correct answer: 6 seconds

At 55 mph, CMV drivers should maintain at least one second per 10 feet of vehicle length plus an extra second, which typically works out to 6 or more seconds.

Question 26: When hauling a load that is 14 feet wide, what is required?

Only a slow-moving vehicle sign
Special permits and possibly a pilot car or escort (Correct answer)
Additional axles on the trailer
A pilot car only

Correct answer: Special permits and possibly a pilot car or escort

Loads exceeding legal width limits (typically 8.5 feet) require special permits and may require pilot cars or escorts depending on state regulations.

Question 27: Hydroplaning in a commercial vehicle is most likely to occur when?

Driving at high speed over standing water (Correct answer)
Making a wide right turn
Driving uphill at low speeds
Braking lightly on dry pavement

Correct answer: Driving at high speed over standing water

Hydroplaning occurs when tires lose contact with the road surface due to water buildup, and is most likely at higher speeds over standing water.

Question 28: What should be the condition of the cargo securement when performing a pre-trip on a loaded flatbed?

All cargo must be properly blocked, braced, tied, or chained (Correct answer)
Cargo securement is checked by the shipper, not the driver
Tarps are only required if cargo exceeds 5 feet in height
Cargo can be loaded loosely if it is a short trip

Correct answer: All cargo must be properly blocked, braced, tied, or chained

The driver is responsible for ensuring all cargo is properly secured before departure regardless of trip length or who loaded the vehicle.

Question 29: What is the maximum length of a safety chain or cable used to secure a converter dolly to the lead trailer?

Safety chains are not required on converter dollies
Exactly 10 feet regardless of trailer length
Long enough to prevent the dolly from swinging wide but short enough to keep it under the trailer if the pintle hook fails (Correct answer)
As long as needed to reach the rear of the lead trailer

Correct answer: Long enough to prevent the dolly from swinging wide but short enough to keep it under the trailer if the pintle hook fails

Safety chains must be short enough to prevent the dolly from touching the ground if it separates, limiting swing and ground contact.

Question 30: Which of the following is a required entry on a driver's daily log?

Truck color and model year
Co-driver's home address
Shipper's phone number
Total miles driven that day (Correct answer)

Correct answer: Total miles driven that day

Total miles driven is a required entry on the daily log, along with date, carrier name, truck number, and co-driver name.

Question 31: You are driving a wide commercial vehicle and find yourself traveling alongside another vehicle for an extended period. What is the primary danger associated with this situation?

It can cause your engine to overheat from lack of airflow.
It increases fuel consumption due to wind resistance.
It violates federal hours-of-service regulations.
You may be trapped and unable to maneuver for an exit or to avoid a hazard. (Correct answer)

Correct answer: You may be trapped and unable to maneuver for an exit or to avoid a hazard.

Traveling alongside other vehicles reduces your available space to the sides, limiting your options. This can trap you, preventing you from changing lanes to take an exit or, more critically, from swerving to avoid a hazard in the road.

Question 32: A CLP applicant has resided in the US for 6 months after moving from another country. Are they eligible?

Yes, provided they can prove domicile in their current state (Correct answer)
No, only US citizens may obtain a CLP
No, must reside in the US for at least 1 year
Yes, any legal resident can apply immediately

Correct answer: Yes, provided they can prove domicile in their current state

Legal US residents can apply for a CLP by proving domicile (primary residence) in the state where they apply, regardless of how long they've been in the country.

Question 33: What is the correct way to use mirrors to monitor a trailer while driving?

Regularly check both side mirrors every 8–10 seconds to monitor trailer tracking, tire condition, and surrounding traffic (Correct answer)
Use mirrors only in urban driving because highway speeds make them unreliable
Check mirrors only when changing lanes
Check mirrors only when backing or parking the trailer

Correct answer: Regularly check both side mirrors every 8–10 seconds to monitor trailer tracking, tire condition, and surrounding traffic

Frequent mirror checks every 8–10 seconds help you monitor trailer alignment, spot tire problems, and stay aware of surrounding vehicles.

Question 34: What is the prerequisite for obtaining a CLP?

You must be a U.S. citizen
You must have at least 3 years of driving experience
You need a valid non-commercial driver's license (Correct answer)
You need to pass a drug test

Correct answer: You need a valid non-commercial driver's license

To obtain a Commercial Learner's Permit (CLP), applicants must first possess a valid non-commercial driver's license. This prerequisite ensures that individuals already have fundamental driving skills and a basic understanding of traffic laws. The CLP then allows them to begin learning the specialized skills required for operating commercial motor vehicles under supervision, building upon their existing driving foundation.

Question 35: Which of the following is tested as part of the 'coupling and uncoupling' section for a Class A CDL skills test?

Proper procedure for connecting and disconnecting the tractor from the trailer (Correct answer)
Knowledge of weight distribution across all axles
Ability to back a trailer into a loading dock without assistance
Pre-trip check of fifth wheel kingpin clearance only

Correct answer: Proper procedure for connecting and disconnecting the tractor from the trailer

Coupling and uncoupling tests the driver's ability to safely connect and disconnect a tractor-trailer combination per FMCSA procedures.

Question 36: Two serious traffic violations within a 3-year period while operating a CMV will result in a CDL disqualification of:

60 days (Correct answer)
30 days
90 days
180 days

Correct answer: 60 days

Two serious traffic violations within a 3-year period result in a 60-day CDL disqualification.

Question 37: What document must accompany a shipment of hazardous materials and be accessible to the driver at all times?

Shipping papers (Correct answer)
Hazmat permit
Bill of lading only
Cargo manifest

Correct answer: Shipping papers

Shipping papers (such as a bill of lading or manifest) must list the hazardous materials and be kept within reach of the driver or in a door pouch when the vehicle is moving.

Question 38: A driver is performing an in-cab inspection and notices that the oil pressure gauge is not rising to the normal operating range after starting the engine. What is the most appropriate action to take?

Drive the vehicle for a few miles to see if the pressure builds up.
Assume the gauge is faulty and continue with the inspection.
Shut off the engine immediately and report the issue. (Correct answer)
Rev the engine to a high RPM to increase the oil pressure.

Correct answer: Shut off the engine immediately and report the issue.

Low or no oil pressure can cause severe engine damage very quickly. The correct and safest action is to shut down the engine immediately to prevent catastrophic failure and report the defect for repair. Continuing to operate the vehicle could lead to a complete engine seizure.

Question 39: Which activity is classified as off-duty time and does NOT count toward a driver's on-duty hours?

Waiting at a shipper
Loading cargo
Sleeping in a sleeper berth (Correct answer)
Performing a vehicle inspection

Correct answer: Sleeping in a sleeper berth

Time spent resting in a sleeper berth is classified as off-duty and does not count toward on-duty hours.

Question 40: A driver has a CLP but their regular driver's license has expired. They may:

Operate CMVs only if a CDL holder is present
Not operate any motor vehicle, including CMVs (Correct answer)
Operate CMVs only in intrastate commerce
Continue to drive CMVs since the CLP serves as their driving credential

Correct answer: Not operate any motor vehicle, including CMVs

A CLP does not replace a valid state driver's license — if the underlying license is expired, the driver cannot legally operate any vehicle.

Question 41: Which of the following materials requires the driver to stop before crossing railroad tracks regardless of other traffic conditions?

Any cargo weighing over 10,000 lbs
Any vehicle with a GVWR over 26,001 lbs
Any refrigerated trailer unit
Any vehicle transporting placardable quantities of hazardous materials (Correct answer)

Correct answer: Any vehicle transporting placardable quantities of hazardous materials

Vehicles carrying placardable amounts of hazardous materials must always stop 15–50 feet before railroad crossings, look and listen, and proceed only when safe.

Question 42: What is the minimum age requirement for a person to obtain a CLP to operate a commercial motor vehicle in interstate commerce?

19 years old
16 years old
18 years old
21 years old (Correct answer)

Correct answer: 21 years old

Federal law requires drivers to be at least 21 years old to operate a CMV in interstate commerce, and the CLP for interstate driving follows the same age standard.

Question 43: A driver notices the truck is pulling to one side during braking. What is the most likely cause?

The steering wheel is not centered during the stop
Air pressure is too high in the brake system
Uneven brake adjustment or a dragging brake on one side (Correct answer)
The load is centered too far forward

Correct answer: Uneven brake adjustment or a dragging brake on one side

Uneven braking force — caused by misadjusted or dragging brakes — pulls the vehicle toward the side with greater stopping force.

Question 44: Which of the following drivers is generally NOT required to maintain records of duty status under federal HOS rules?

A driver transporting hazardous materials interstate
A driver operating within a 150 air-mile short-haul exemption (Correct answer)
A long-haul driver operating across state lines
A driver pulling a combination vehicle overnight

Correct answer: A driver operating within a 150 air-mile short-haul exemption

Drivers who qualify for the short-haul exemption by operating within 150 air miles and returning to their reporting location within 12 hours are not required to maintain RODS.

Question 45: What is the 'applied stroke' of a brake chamber, and why does it matter?

The speed at which brakes are applied during an emergency stop
The pressure required to begin moving the push rod from its rest position
The total length of the push rod when fully retracted; determines brake chamber size selection
The distance the push rod travels when brakes are fully applied; must stay within legal limits to ensure effective braking (Correct answer)

Correct answer: The distance the push rod travels when brakes are fully applied; must stay within legal limits to ensure effective braking

Applied stroke is how far the push rod extends when brakes are applied; excessive stroke reduces braking efficiency and indicates brakes need adjustment.

Question 46: Which HOS provision allows a driver to pause the 14-hour on-duty clock during a rest period?

Short-haul exemption
Adverse driving conditions exception
Sleeper berth split provision (Correct answer)
30-minute break waiver

Correct answer: Sleeper berth split provision

The sleeper berth split allows drivers to pause the 14-hour clock during the qualifying off-duty period taken in the sleeper berth.

Question 47: Which of the following is NOT typically a requirement during the supervised driving phase of obtaining a CLP?

Completing a set number of hours behind the wheel
Driving during daylight hours
Driving under the supervision of a CDL holder
Passing a road skills test before the supervised driving (Correct answer)

Correct answer: Passing a road skills test before the supervised driving

The road skills test is the final practical examination required to obtain a full Commercial Driver's License (CDL), and it is taken *after* the supervised driving phase with a CLP. Therefore, passing a road skills test is not a requirement *before* supervised driving; rather, supervised driving is the preparatory phase leading up to the skills test.

Question 48: When inspecting wheels and rims during a pre-trip, what are you looking for on the lug nuts?

Rust streaks, missing nuts, or cracks around the bolt holes (Correct answer)
Whether white painted marks are aligned
Lug nut torque using a torque wrench
That they are the correct color

Correct answer: Rust streaks, missing nuts, or cracks around the bolt holes

Rust streaks can indicate loose lug nuts rubbing against the wheel, while missing nuts or cracks are direct safety defects.

Question 49: A CMV driver who is found to have a blood alcohol concentration (BAC) of 0.04% or higher while on duty faces:

A verbal warning for a first offense
A fine of no less than $5,000
Being placed out of service for 24 hours (Correct answer)
Immediate revocation of CDL with no appeal

Correct answer: Being placed out of service for 24 hours

A BAC at or above 0.04% while operating a CMV results in being placed out of service for 24 hours.

Question 50: Under the CDL Drug and Alcohol Clearinghouse rules, employers must query the clearinghouse before hiring a CDL driver:

Only for interstate drivers
Only for drivers who will transport hazardous materials
For every pre-employment hire (Correct answer)
Only if the driver was previously disqualified

Correct answer: For every pre-employment hire

Employers must conduct a pre-employment full query of the Drug and Alcohol Clearinghouse for every prospective CDL driver hire.

Question 51: A CMV driver must stop on the side of a highway due to a breakdown. What minimum distance should reflective triangles be placed behind the vehicle?

50 feet, 100 feet, 500 feet
10 feet, 100 feet, 200 feet
100 feet, 100 feet, 100 feet
10 feet, 100 feet, 300 feet (Correct answer)

Correct answer: 10 feet, 100 feet, 300 feet

FMCSA regulations require triangles at approximately 10 feet, 100 feet, and 300 feet to the rear to warn approaching traffic.

CDL Commercial Learner's Permit (CLP) Exam

The Commercial Learner's Permit (CLP) knowledge exam is administered by each state's Department of Motor Vehicles and is required before obtaining a Commercial Driver's License (CDL). It is based on the Federal Motor Carrier Safety Administration (FMCSA) CDL standards. The exam covers general knowledge, air brakes, combination vehicles, pre-trip inspection, cargo handling, hours of service, and adverse driving conditions. Passing score is typically 80%. Applicants must pass the relevant sections for their desired CDL class and endorsements.

Questions

90 min

Time Limit

80%

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