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KS CDL General Knowledge study materials
KS CDL General Knowledge study resources

KS CDL General Knowledge practice questions

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Question 1General Knowledge

A Kansas-licensed driver is operating a commercial motor vehicle and approaches a railroad-highway grade crossing. The vehicle is carrying a placarded quantity of hazardous materials and is not required to stop for traffic control devices. What must the driver do at the crossing?

  1. Stop before the tracks, look and listen, and proceed only when safe Correct answer.
  2. Slow to 20 mph and proceed without stopping
  3. Stop only if a train is visible
  4. Sound the horn and cross without stopping

Explanation

Federal and Kansas rules require a CMV carrying placarded hazardous materials to stop at every railroad-highway grade crossing unless the crossing is exempted, regardless of signal indications. The driver must stop, look both ways, listen, and cross only when the way is clear.

Question 2General Knowledge

Under Kansas law, which of these is the legal blood alcohol concentration threshold at which a commercial driver is considered under the influence while operating a CMV?

  1. 0.04 percent Correct answer.
  2. 0.10 percent
  3. 0.02 percent
  4. 0.08 percent

Explanation

Commercial drivers are held to a stricter standard than other drivers. A BAC of 0.04 percent or higher while operating a CMV is a violation, and a CDL holder may also face penalties for a 0.08 percent or higher in a personal vehicle.

Question 3General Knowledge

A driver must inspect a commercial motor vehicle before beginning a trip. Which item belongs on the pre-trip inspection of the braking system?

  1. The radio antenna height
  2. The slack adjuster push-rod travel Correct answer.
  3. The spare tire tread depth
  4. The color of the brake pedal

Explanation

Pre-trip inspection of air brakes includes checking that push rods and slack adjusters operate within the allowed travel range. Excessive push-rod travel signals that the brakes are out of adjustment and the vehicle should not be driven.

Question 4General Knowledge

A CMV is traveling at highway speed and the driver must stop quickly. Which factor most increases the total stopping distance?

  1. The age of the windshield wipers
  2. The number of mirrors on the cab
  3. The vehicle's total weight and speed Correct answer.
  4. The color of the trailer

Explanation

Stopping distance is the sum of perception distance, reaction distance, and braking distance. Heavier vehicles at higher speeds carry more momentum, and the brakes need more distance to dissipate that energy, so weight and speed dominate total stopping distance.

Question 5General Knowledge

A driver is backing a tractor-trailer and cannot see directly behind the trailer. What is the safest practice?

  1. Use a helper or spotter whenever possible Correct answer.
  2. Back toward the driver's side without checking
  3. Back quickly to reduce exposure time
  4. Rely only on the convex mirrors

Explanation

Backing is one of the highest-risk maneuvers for large vehicles because of blind spots. Using a spotter who stays visible in the mirrors, and stopping if the spotter is lost from view, is the recommended safe practice.

Question 6General Knowledge

Which document must a commercial driver present to a law enforcement officer during a roadside inspection?

  1. The CDL and any required endorsements Correct answer.
  2. A vehicle warranty card
  3. A copy of the bill of lading only
  4. A personal vehicle registration only

Explanation

A driver must carry and present a valid CDL with the endorsements required for the vehicle and cargo being operated. Other documents such as registration and shipping papers may also be requested, but the CDL is the core credential.

Question 7General Knowledge

A CMV tire has a large bulge on the sidewall and visible cord fabric. What should the driver do?

  1. Cover the bulge with a reflective marker
  2. Inflate the tire to maximum pressure
  3. Continue at reduced speed to the next stop
  4. Remove the vehicle from service until the tire is replaced Correct answer.

Explanation

A bulge or exposed cord indicates structural tire damage that can lead to a blowout. The vehicle must be taken out of service and the tire replaced before it is driven.

Question 8General Knowledge

When loading cargo in a commercial vehicle, what is the primary purpose of securing the load?

  1. To reduce tire wear
  2. To prevent the load from shifting or falling Correct answer.
  3. To make the trailer easier to wash
  4. To improve fuel economy

Explanation

Cargo must be secured so it cannot shift, spill, or fall from the vehicle. Shifting loads can cause loss of control, and falling cargo creates a hazard for other road users.

Question 9General Knowledge

A driver is descending a long mountain grade with a heavy load. Which technique best controls speed and prevents brake fade?

  1. Ride the brakes continuously down the grade
  2. Shift to neutral to coast
  3. Shift to a lower gear and use the engine brake before descending Correct answer.
  4. Accelerate to reach the bottom faster

Explanation

Selecting a lower gear before the descent uses engine braking to control speed and reduces reliance on the service brakes. Continuous braking overheats the brakes and causes fade, which can lead to runaway.

Question 10General Knowledge

An air-brake-equipped CMV shows low air pressure and the low-pressure warning buzzer sounds. What should the driver do?

  1. Continue driving until the next scheduled service
  2. Ignore the warning if the brakes still feel firm
  3. Pump the brake pedal repeatedly to build pressure
  4. Stop and investigate the air loss before moving Correct answer.

Explanation

A low-air warning indicates the system cannot maintain safe operating pressure. The driver must stop in a safe location and find the cause before continuing, because braking performance may be compromised.

Question 11General Knowledge

A driver is operating a CMV in heavy rain and the tires begin to hydroplane. What is the correct response?

  1. Brake hard and steer sharply
  2. Accelerate to regain traction
  3. Ease off the accelerator and steer smoothly Correct answer.
  4. Turn the steering wheel rapidly

Explanation

Hydroplaning occurs when water lifts the tires off the road surface. Easing off the accelerator lets the tires regain contact, and smooth steering avoids a skid; hard braking or sharp turns can cause loss of control.

Question 12General Knowledge

A commercial driver must make a right turn at an intersection. Why should the driver swing wide or use a proper turn path?

  1. To increase speed through the turn
  2. To keep the rear wheels from crossing the curb Correct answer.
  3. To shorten the turning radius
  4. To avoid using turn signals

Explanation

Large vehicles have off-tracking, meaning the rear wheels follow a tighter path than the front wheels. A proper turn path keeps the trailer and rear wheels from striking the curb or nearby objects.

Question 13General Knowledge

A driver is following another vehicle on a dry highway at 55 mph. Which following distance is recommended for a loaded CMV?

  1. At least one second for each 10 feet of vehicle length Correct answer.
  2. Half the length of the vehicle
  3. Two seconds
  4. One second

Explanation

A common rule is to allow at least one second of following distance for each 10 feet of vehicle length at speeds below 40 mph, adding one second above that. For a 55 mph loaded combination, this yields a substantially longer gap than a passenger car would use.

Question 14General Knowledge

A driver must couple a tractor to a semitrailer. After backing under the trailer, what should be done before the pull test?

  1. Release the trailer brakes only
  2. Lock the fifth-wheel jaws and connect the air lines and electrical cord Correct answer.
  3. Raise the landing gear fully and drive away
  4. Lower the trailer onto the frame

Explanation

After backing under the trailer, the driver must confirm the kingpin is locked in the fifth wheel, connect the air lines and electrical cord, and then perform a pull test. The landing gear is raised after coupling is verified.

Question 15General Knowledge

An accident occurs and a CMV is carrying hazardous materials. Which action is required of the driver?

  1. Conceal the placards
  2. Move the hazardous cargo by hand
  3. Warn other traffic and notify authorities Correct answer.
  4. Leave the scene to find a phone

Explanation

After a hazmat incident, the driver should warn other traffic, keep people away, and notify emergency responders and the carrier. Placards must remain visible so responders can identify the hazard.

Question 16General Knowledge

A driver is operating a vehicle with a manual transmission on a steep upgrade and the vehicle begins to roll backward. What is the best immediate action?

  1. Shift into a higher gear
  2. Apply the parking brake and use the clutch and throttle to start again Correct answer.
  3. Release the clutch quickly and accelerate hard
  4. Coast backward to gain momentum

Explanation

On a steep upgrade, the parking brake holds the vehicle while the driver engages the clutch and throttle. Once the vehicle begins to move forward, the parking brake is released to prevent rolling backward into traffic.

Question 17General Knowledge

A CMV driver is approaching a work zone with reduced lane width and workers present. What is the safest action?

  1. Maintain highway speed to clear the zone quickly
  2. Reduce speed and increase following distance Correct answer.
  3. Sound the horn continuously
  4. Use the shoulder to pass slower traffic

Explanation

Work zones present narrowed lanes, workers, and changing traffic patterns. Reducing speed and increasing following distance gives the driver more time to react and protects workers and other motorists.

Question 18General Knowledge

A driver is inspecting an air-brake system and performs a static leak test. What is the purpose of this test?

  1. To check the tire pressure
  2. To confirm the compressor builds pressure quickly
  3. To detect air loss in the system while the brakes are applied Correct answer.
  4. To verify the parking brake holds on a grade

Explanation

The static leak test checks whether air pressure drops excessively when the brakes are fully applied and held. A significant drop indicates a leak that must be repaired before the vehicle is operated.

Question 19General Knowledge

A driver must transport a load that exceeds the legal height limit. What is required before the trip?

  1. An oversize permit and proper route planning Correct answer.
  2. Removal of the vehicle's mirrors
  3. Only a warning flag at the rear
  4. No special action if the load is secure

Explanation

Loads exceeding legal height, width, or weight limits generally require an oversize or overweight permit and a route that can accommodate the dimensions. Flags and lights may also be required, but they do not replace the permit.

Question 20General Knowledge

A driver is operating a CMV and the front wheels begin to shimmy at highway speed. What is the most appropriate response?

  1. Brake hard immediately
  2. Reduce speed gradually and inspect the steering and tires Correct answer.
  3. Accelerate to stabilize the vehicle
  4. Turn sharply to test the steering

Explanation

Front-wheel shimmy can indicate tire, wheel, or steering-component problems. Reducing speed gradually and stopping to inspect the front end prevents a loss of steering control.

Question 21General Knowledge

A driver must decide whether to use the engine brake on a wet or icy road. What is the safest approach?

  1. Use the engine brake only at high speed
  2. Use the engine brake at full power
  3. Rely on the engine brake instead of the service brakes
  4. Disable or reduce engine braking on slippery surfaces Correct answer.

Explanation

Engine brakes can cause the drive wheels to lose traction on wet or icy pavement, leading to a skid. On slippery surfaces, the driver should reduce or disable engine braking and use smooth, gentle service braking.

Question 22General Knowledge

A driver is reviewing hours-of-service records and realizes the driving limit for the day has been reached while still 30 miles from the terminal. What is the correct course of action?

  1. Continue driving because the destination is close
  2. Stop and take the required rest before continuing Correct answer.
  3. Record the remaining miles as off-duty
  4. Increase speed to arrive sooner

Explanation

Hours-of-service limits are maximums, not targets, and the driver may not exceed them to reach a destination. The driver must stop and take the required rest period before resuming, and records must accurately reflect the time.

Question 23General Knowledge

A driver notices the trailer brakes are not releasing fully after the parking brake is disengaged. Which diagnosis is most consistent with this symptom?

  1. The headlights are misaligned
  2. The trailer air-supply line is restricted or the relay valve is faulty Correct answer.
  3. The engine oil is low
  4. The windshield washer fluid is empty

Explanation

Trailer brakes that drag after release suggest an air-supply restriction or a faulty relay valve that is not venting pressure. The vehicle should be inspected and repaired before operation because dragging brakes can overheat and fail.

Question 24General Knowledge

A driver is hauling a liquid load in a partially filled tanker. How does the movement of the liquid affect vehicle handling?

  1. It eliminates the need for a reduced speed on curves
  2. It has no effect if the tank is baffled
  3. It creates a shifting weight that can cause rollover or loss of control Correct answer.
  4. It lowers the center of gravity and improves stability

Explanation

Liquid cargo moves as the vehicle turns or brakes, shifting weight and raising the risk of rollover, especially in partially filled tanks. Drivers must slow down on curves and avoid abrupt maneuvers.

Question 25General Knowledge

A driver is descending a grade and the service brakes begin to fade. What is the most effective emergency action?

  1. Shift to neutral and coast
  2. Downshift and use engine braking while applying brakes firmly and steadily Correct answer.
  3. Pump the brakes rapidly and accelerate
  4. Turn off the engine to stop the vehicle

Explanation

When brakes fade, downshifting uses engine compression to slow the vehicle while firm, steady brake application helps recover some braking force. Pumping, coasting, or shutting off the engine can worsen control and steering.

Question 26General Knowledge

Under Kansas CDL rules, what is the minimum age at which a person may be issued a commercial driver's license to drive interstate?

  1. 19 years
  2. 18 years
  3. 16 years
  4. 21 years Correct answer.

Explanation

Federal and Kansas CDL rules require a driver to be at least 21 years old to operate a CMV across state lines or to haul hazardous materials. Drivers aged 18 to 20 may hold a CDL that is restricted to intrastate operation only.

Question 27General Knowledge

A Kansas CMV driver is convicted of a first offense of driving a CMV with a blood alcohol concentration of 0.04 percent. What is the standard consequence to the driver's CDL?

  1. A warning letter with no loss of privileges
  2. A one-year disqualification Correct answer.
  3. A 60-day suspension with probation
  4. A 30-day suspension

Explanation

A first conviction for driving a CMV with a BAC of 0.04 or higher results in a one-year disqualification of the CDL. The disqualification is longer if the offense occurred while carrying hazardous materials requiring placards.

Question 28General Knowledge

Which class of Kansas CDL is required to operate a combination vehicle with a gross combination weight rating over 26,000 pounds, including a towed unit over 10,000 pounds?

  1. Class C
  2. Class B
  3. Class A Correct answer.
  4. Class M

Explanation

Class A covers combination vehicles whose gross combination weight rating exceeds 26,000 pounds and whose towed unit exceeds 10,000 pounds. Class B covers single vehicles over 26,000 pounds, and Class C covers smaller vehicles carrying passengers or placarded hazmat.

Question 29General Knowledge

Before backing a tractor-trailer, what is the most important first step for the driver?

  1. Turn on the four-way flashers and rely on mirrors
  2. Get out and check the area behind the trailer Correct answer.
  3. Ask a passenger to watch from inside the cab
  4. Sound the horn twice and back immediately

Explanation

Blind spots behind a trailer are large, so the driver should walk around and inspect the backing area before moving. Looking for pedestrians, obstacles, and clearance first prevents most backing collisions.

Question 30General Knowledge

What is the purpose of a pre-trip inspection of a CMV?

  1. To check that the cargo matches the bill of lading
  2. To find problems that could cause a breakdown or crash Correct answer.
  3. To record the vehicle's fuel level for billing
  4. To satisfy insurance paperwork requirements

Explanation

The pre-trip inspection is a safety check designed to catch defects such as brake, tire, light, or coupling problems before they cause a crash or roadside breakdown. It is required before each trip and documented in the driver's report.

Question 31General Knowledge

Which of the following best describes the correct way to hold the steering wheel when driving a CMV?

  1. One hand resting on the shift lever
  2. One hand at the top of the wheel
  3. Both hands on opposite sides of the wheel Correct answer.
  4. Both hands at the bottom of the wheel

Explanation

Placing both hands on opposite sides of the wheel provides the best control and keeps the driver ready to steer around hazards. One-handed or low-grip positions reduce control, especially during sudden maneuvers.

Question 32General Knowledge

When should a driver use the parking brake on a CMV?

  1. Whenever the vehicle is parked Correct answer.
  2. Only when the engine is off
  3. Only when the trailer is empty
  4. Only when the vehicle is on a hill

Explanation

The parking brake should be set whenever the vehicle is parked, regardless of slope or load. It prevents the vehicle from rolling and is a required part of secure parking.

Question 33General Knowledge

A driver is approaching a railroad crossing with no gates and no flashing lights. What should the driver do?

  1. Follow the vehicle ahead closely
  2. Stop, look, and listen before crossing Correct answer.
  3. Honk and proceed without stopping
  4. Speed up to cross before a train arrives

Explanation

At passive crossings without gates or signals, the driver must stop, look both ways, and listen for an approaching train before proceeding. Large vehicles need extra clearance time, so caution is essential.

Question 34General Knowledge

A driver is checking the slack adjusters on an air-brake system during a pre-trip inspection. What is the driver checking for?

  1. Excessive free play or movement Correct answer.
  2. The color of the air lines
  3. The level of the coolant
  4. The tread depth of the tires

Explanation

Slack adjusters transfer the brake chamber's pushrod force to the brake shoes, and excessive free play indicates the brakes need adjustment. Checking them helps confirm the brakes will apply fully.

Question 35General Knowledge

A driver is operating a CMV with a manual transmission on a steep downgrade. Which gear should the driver select before starting down?

  1. A gear lower than the one used to climb the grade Correct answer.
  2. The highest gear available
  3. The gear that matches highway cruising speed
  4. Neutral to save fuel

Explanation

Selecting a lower gear before descending uses engine braking to control speed and reduces reliance on the service brakes. A gear lower than the climb gear is the standard recommendation for steep grades.

Question 36General Knowledge

A driver is inspecting a trailer's coupling system. Which component confirms the kingpin is fully engaged?

  1. The trailer light cord
  2. The mud flap
  3. The fifth-wheel locking jaws Correct answer.
  4. The landing gear

Explanation

The fifth-wheel locking jaws must close around the kingpin to secure the trailer. A visual check plus a tug test confirms the jaws are locked before the driver pulls away.

Question 37General Knowledge

A driver is hauling a load of steel coils. Which securement method is most appropriate?

  1. Rope tied across the top of the coils
  2. Wooden blocks without tie-downs
  3. A tarp only
  4. Chains and binders with edge protection Correct answer.

Explanation

Heavy steel coils require chains and binders rated for the load, with edge protection to prevent damage to the chain. Rope or tarp alone cannot restrain such heavy freight.

Question 38General Knowledge

A driver is driving at night and an oncoming vehicle's high beams cause glare. What is the best response?

  1. Look directly at the oncoming lights
  2. Look toward the right edge of the roadway Correct answer.
  3. Close one eye until the vehicle passes
  4. Turn on high beams in response

Explanation

Looking toward the right edge of the lane helps the driver maintain position while avoiding direct glare. It reduces the temporary blinding effect of oncoming high beams.

Question 39General Knowledge

A driver is transporting a load that extends four feet beyond the rear of the vehicle. What is required?

  1. Only a warning triangle at night
  2. A red or orange flag during daylight and a light at night Correct answer.
  3. Nothing, because the load is short
  4. A police escort at all times

Explanation

Loads extending four feet or more beyond the rear must be marked with a flag in daylight and a red light at night so other drivers can see the overhang. The marking warns following traffic of the extended length.

Question 40General Knowledge

A driver is approaching a sharp curve posted with an advisory speed lower than the posted limit. What should the driver do?

  1. Brake hard while inside the curve
  2. Slow to the advisory speed before entering the curve Correct answer.
  3. Maintain the posted limit through the curve
  4. Accelerate to stabilize the vehicle

Explanation

The advisory speed reflects the safe speed for the curve under normal conditions, and a CMV's high center of gravity makes it prone to rollover. Slowing before the curve keeps braking out of the turn and maintains control.

Question 41General Knowledge

A driver is operating a CMV with a placarded load of flammable liquid. What is required when the vehicle is parked?

  1. Parking in any lot near a restaurant
  2. Parking with the engine running
  3. Parking under an overpass
  4. Parking away from crowds and ignition sources Correct answer.

Explanation

Placarded hazmat vehicles must be parked away from crowds, tunnels, and ignition sources to reduce the risk of a catastrophic incident. Idling under an overpass or near buildings is prohibited in many cases.

Question 42General Knowledge

A driver's vehicle has a hydraulic brake system, and the brake pedal feels spongy and sinks toward the floor. What is the most likely cause?

  1. Low tire pressure
  2. Air in the brake lines or a fluid leak Correct answer.
  3. A clogged air filter
  4. A worn steering gear

Explanation

A spongy pedal that sinks usually indicates air in the hydraulic lines or a fluid leak, both of which reduce braking force. The vehicle should be taken out of service until the system is repaired.

Question 43General Knowledge

A driver is driving in fog and visibility drops sharply. Which action is safest?

  1. Increase speed to leave the fog quickly
  2. Turn on hazard lights and stop in the travel lane
  3. Use low beams and slow down Correct answer.
  4. Use high beams to see farther

Explanation

Low beams reduce glare reflected by fog, and slowing down increases reaction time when visibility is limited. High beams reflect off the fog and worsen visibility.

Question 44General Knowledge

A driver is performing a brake test on a tractor-trailer combination. The trailer brakes must apply when the driver uses the hand valve. What does this check confirm?

  1. That the kingpin is engaged
  2. That the tires are properly inflated
  3. That the trailer brakes are receiving air and functioning Correct answer.
  4. That the trailer's electrical system works

Explanation

Using the hand valve supplies air to the trailer brakes only, so the trailer's response confirms the brakes receive air and apply. This isolates the trailer system from the tractor brakes during the test.

Question 45General Knowledge

A driver's CMV has a rear-wheel skid on a slippery road. What should the driver do to regain control?

  1. Accelerate to pull the vehicle straight
  2. Release the brakes and steer in the direction of the skid Correct answer.
  3. Turn the wheel sharply to the left
  4. Apply the brakes harder and steer opposite the skid

Explanation

Releasing the brakes restores wheel rotation, and steering in the direction of the skid aligns the vehicle with its path of travel. Overbraking or turning against the skid worsens the loss of control.

Question 46General Knowledge

A driver is inspecting the tires on a CMV and finds a tread depth of 3/32 inch on a front steering axle tire. What does this indicate?

  1. The tire is acceptable for all positions
  2. The tire is new and needs no attention
  3. The tire is below the minimum for a steering axle Correct answer.
  4. The tire is acceptable only for trailer use

Explanation

Steering axle tires must have at least 4/32 inch of tread depth, so 3/32 inch fails the standard and the tire must be replaced. Other positions have a lower minimum of 2/32 inch.

Question 47General Knowledge

A driver is descending a long grade when the vehicle's speed begins to climb despite engine braking. What is the safest next step?

  1. Use the service brakes firmly and briefly to reduce speed Correct answer.
  2. Shift to a higher gear
  3. Coast in neutral to save the brakes
  4. Turn off the engine to slow down

Explanation

Firm, brief brake applications shed speed without overheating the brakes, and the driver should downshift if needed. Turning off the engine or coasting in neutral removes engine braking and power steering assist.

Question 48General Knowledge

A driver is coupling a tractor to a trailer and the fifth-wheel jaws fail to lock. What is the most likely cause?

  1. The landing gear is fully raised
  2. The kingpin is too far forward
  3. The trailer lights are disconnected
  4. The trailer is too high or too low for the fifth wheel Correct answer.

Explanation

If the trailer height does not match the fifth wheel, the kingpin can pass over the jaws without locking. The driver should adjust the trailer height and repeat the coupling procedure.

Question 49General Knowledge

A driver is inspecting a placarded hazmat load and notices a torn placard. What should the driver do?

  1. Cover the placard with tape
  2. Replace the damaged placard before moving Correct answer.
  3. Continue the trip because the placard is only decorative
  4. Remove the placard entirely

Explanation

Placards communicate the hazard to emergency responders and must be legible and properly displayed. A torn or missing placard must be replaced before the vehicle moves.

Question 50General Knowledge

A driver is driving a CMV at highway speed when a front tire blows out. What is the safest immediate action?

  1. Hold the wheel firmly and slow gradually Correct answer.
  2. Turn sharply to the shoulder
  3. Brake hard and steer off the road immediately
  4. Accelerate to stabilize the vehicle

Explanation

A front tire blowout causes strong pull, so the driver should grip the wheel firmly, ease off the accelerator, and slow gradually before moving off the road. Hard braking or sharp steering can cause a loss of control.