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Louisiana CDL General Knowledge study materials
Louisiana CDL General Knowledge study resources

Louisiana CDL General Knowledge practice questions

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Question 1General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

During a pre-trip inspection, you check the slack adjusters on a vehicle with air brakes. What should you look for?

  1. That the slack adjuster rotates freely with the parking brake set
  2. That the slack adjuster is welded firmly to the push rod
  3. That the push rod moves at least six inches when the brake is applied
  4. That the push rod travel stays within the limit marked on the chamber Correct answer.

Explanation

Slack adjusters take up the gap as brake linings wear, and excessive push rod travel means the brakes are out of adjustment and may not apply fully. The push rod travel must stay within the limit marked on the brake chamber. If travel is too long, the brakes need adjustment before the vehicle is driven.

Question 2General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

You are driving a loaded tractor-trailer and must stop on a steep downgrade. What is the safest practice?

  1. Set the parking brakes and leave the transmission in gear
  2. Hold the vehicle with the clutch and let the engine idle
  3. Shift to neutral and rely on the service brakes
  4. Use the service brakes to stop, then set the parking brake and place the transmission in a low gear Correct answer.

Explanation

On a grade, the parking brake alone may not hold a heavy load, so you stop with the service brakes, set the parking brake, and leave the transmission in a low gear or park as a backup. Turning the wheels toward the curb or shoulder adds another layer of protection. Never coast in neutral, because you lose engine braking and control.

Question 3General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

When should you downshift in a manual transmission vehicle?

  1. After the engine begins to lug or knock
  2. Before entering a curve or starting down a grade Correct answer.
  3. While the clutch is fully released in neutral
  4. Only after the brakes have faded

Explanation

Downshift before you need the lower gear, such as before a curve or the start of a downgrade, while engine speed and road speed are still matched. Waiting until the engine lugs means you have already lost control of speed. Downshifting one gear at a time and matching engine speed protects the transmission and keeps you in control.

Question 4General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

What is the proper adjustment for your mirrors before a trip?

  1. Set them so your own trailer fills most of each mirror
  2. Aim them mostly at the sky to reduce glare
  3. Aim them so you can see the rear tires and the lane beside the trailer Correct answer.
  4. Point them inward so the cab interior is visible

Explanation

Mirrors should be set so you can see the sides of your vehicle, the rear tires, and the traffic lanes beside and behind you. That view lets you monitor blind spots and lane position. Mirrors filled with sky or with your own trailer hide the areas you need to watch.

Question 5General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

You are driving a slow-moving vehicle on a two-lane road and a line of cars is behind you. What should you do?

  1. Pull off the road at a safe place and let the traffic pass Correct answer.
  2. Wave the cars past on a curve
  3. Keep your speed and let them pass when they choose
  4. Speed up beyond the posted limit to clear them

Explanation

When you are holding up a line of traffic on a two-lane road, the courteous and safe move is to pull off at a safe spot and let them pass. Signaling others to pass on a curve or hill is dangerous because you cannot see oncoming traffic. Speeding to clear them is not a solution and may be unlawful.

Question 6General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

What following distance should you maintain behind the vehicle ahead under ideal conditions?

  1. At least one second at any speed
  2. One second for each ten feet of vehicle length Correct answer.
  3. A fixed 100 feet regardless of speed
  4. Two seconds at speeds under 40 mph only

Explanation

A common rule for large vehicles is one second of following distance for each ten feet of vehicle length at speeds under 40 mph, with an extra second added above that. This scales the gap to the size of the vehicle and the speed. A fixed distance or a single second does not account for stopping distance.

Question 7General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

Your vehicle starts to skid on a wet road. What should you do first?

  1. Accelerate to pull out of the skid
  2. Take your foot off the accelerator and steer in the direction you want to go Correct answer.
  3. Apply the brakes hard and steer against the skid
  4. Turn the steering wheel sharply back and forth

Explanation

In a skid, release the accelerator so the tires can regain traction and steer where you want the vehicle to go. Hard braking or sharp steering corrections can worsen the skid. Accelerating adds speed the tires cannot use and deepens the loss of traction.

Question 8General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

You are approaching a railroad crossing with no gates and no flashing lights. What should you do?

  1. Stop only if you see a train within 100 feet
  2. Maintain speed so you clear the crossing quickly
  3. Slow down, look and listen, and cross only when you are sure no train is coming Correct answer.
  4. Sound your horn and proceed without slowing

Explanation

At a passive crossing you must slow down, roll down the window if needed, and look and listen in both directions before crossing. Trains can appear faster than they seem and cannot stop quickly. Only proceed when you are certain no train is approaching.

Question 9General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

How should you secure cargo in a truck bed?

  1. Cover it with a tarp only
  2. Rely on the weight of the cargo to hold it in place
  3. Stack it above the side rails for visibility
  4. Use tie-downs rated for the load and check them during the trip Correct answer.

Explanation

Cargo must be secured with tie-downs and restraints strong enough for the load, and the securement should be checked during the trip as straps can loosen. Weight alone does not keep cargo from shifting or falling off. Tarps cover cargo but do not secure it.

Question 10General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

You are driving a vehicle with air brakes and notice the low air pressure warning comes on. What should you do?

  1. Continue to the next scheduled stop
  2. Shift to a higher gear to reduce engine load
  3. Pump the brakes repeatedly to build pressure
  4. Stop as soon as it is safe and check the system Correct answer.

Explanation

A low air pressure warning means the air system may not be able to apply the brakes, so you should stop at the first safe place and investigate. Continuing to drive risks losing braking ability. Pumping the brakes further depletes air pressure rather than restoring it.

Question 11General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

What is the first sign of fatigue while driving?

  1. Sharper reaction time
  2. A sudden burst of energy
  3. Frequent yawning and heavy eyelids Correct answer.
  4. Increased alertness

Explanation

Yawning, heavy eyelids, drifting, and difficulty focusing are early warning signs of fatigue. Fatigue slows reaction time and judgment long before a driver admits being tired. The safe response is to stop and rest, not to push through.

Question 12General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

How long does it typically take for the body to eliminate the alcohol in one standard drink?

  1. About five minutes
  2. About 15 minutes
  3. About one hour Correct answer.
  4. About three hours

Explanation

The body generally processes about one standard drink per hour, and nothing speeds this up. Coffee, cold showers, and food do not lower blood alcohol concentration. Time is the only thing that removes alcohol from the body.

Question 13General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

When backing a large vehicle, which practice is safest?

  1. Back as quickly as possible to reduce exposure
  2. Back toward the driver's side without checking
  3. Back only when necessary and use a helper or get out and check Correct answer.
  4. Rely on the mirrors alone

Explanation

Backing is one of the most dangerous maneuvers for a large vehicle because of blind spots. Back only when necessary, and use a helper or walk around the vehicle to check the path first. Mirrors alone leave large blind areas behind the trailer.

Question 14General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

What does the term 'space cushion' mean in defensive driving?

  1. The distance from the curb when parked
  2. The gap between the trailer and the cab
  3. The padding inside the cab
  4. The distance you keep between your vehicle and hazards around it Correct answer.

Explanation

A space cushion is the buffer of distance you maintain around your vehicle so you have time to react to hazards ahead, beside, and behind. It includes following distance and room to change lanes or stop. Maintaining it is central to managing speed and space.

Question 15General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

You are driving at night and an oncoming vehicle's high beams blind you. What should you do?

  1. Flash your high beams repeatedly
  2. Look toward the right edge of your lane and slow down Correct answer.
  3. Speed up to pass the vehicle quickly
  4. Stare at the oncoming lights to judge distance

Explanation

When blinded by oncoming high beams, look toward the right edge of your lane to keep your position and slow down until your vision recovers. Flashing your lights or staring at the glare worsens the problem. Speeding up while you cannot see is dangerous.

Question 16General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

What should you do if your brakes fail on a downgrade?

  1. Shift to neutral and coast
  2. Downshift, use engine braking, and look for an escape ramp or safe place to stop Correct answer.
  3. Turn off the engine immediately
  4. Apply the parking brake at full force instantly

Explanation

If brakes fail, downshift to use engine braking and look for an escape ramp, runaway truck ramp, or other safe place to stop. Coasting in neutral removes engine braking and lets speed build. Slamming the parking brake can lock wheels and cause a skid.

Question 17General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

Why should you avoid using the jake brake in a residential area at night?

  1. It causes the engine to overheat
  2. It increases fuel consumption
  3. It disables the service brakes
  4. It may be prohibited by local ordinance because of noise Correct answer.

Explanation

Engine (jake) brakes are loud, and many communities restrict their use in residential areas, especially at night. Signs often prohibit them. Using them where prohibited can bring fines even though they are useful on long grades.

Question 18General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

When must you stop before a railroad crossing?

  1. Only at night
  2. Only when the gates are down
  3. Only when carrying passengers
  4. When a train is visible or a signal indicates an approaching train Correct answer.

Explanation

You must stop when a train is approaching, when warning signals or gates indicate a train, or when a flagger directs you to stop. You should never try to beat a train. Stopping only when gates are down misses crossings without gates and trains that are hard to see.

Question 19General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

Assume a level road, the same initial speed and reaction time, and unchanged braking force. What is the effect of a heavy load on a vehicle's stopping distance?

  1. It only affects steering, not braking
  2. It shortens stopping distance
  3. It lengthens stopping distance Correct answer.
  4. It has no effect on stopping distance

Explanation

With speed and reaction time unchanged, reaction distance stays the same. A heavier load increases the energy the brakes must absorb. If braking force also remains unchanged, braking distance and total stopping distance increase. Actual loaded-versus-empty truck comparisons can differ because loading affects traction.

Question 20General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

You are hauling cargo that may shift. What should you do before driving?

  1. Assume the shipper secured it properly
  2. Loosen the straps so the load can settle
  3. Check the load and secure it, then recheck after driving a short distance Correct answer.
  4. Drive fast to reduce the time the load can shift

Explanation

The driver is responsible for ensuring cargo is properly secured, so check the load before driving and recheck it after a short distance and periodically during the trip. Straps can loosen as the load settles. Loosening straps or assuming the shipper did the job risks a spill.

Question 21General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

What does 'covering the brake' mean?

  1. Using the trailer brake only
  2. Keeping your foot over the brake pedal without pressing it, ready to stop Correct answer.
  3. Riding the brake down a hill
  4. Applying the brake fully at all times

Explanation

Covering the brake means holding your foot over the pedal without applying pressure so you can react faster to a hazard. It is useful in heavy traffic or when approaching a situation that may require a quick stop. It is not the same as riding the brake, which overheats the brakes.

Question 22General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

What is the purpose of the retarder on a heavy vehicle?

  1. To increase engine power on hills
  2. To help slow the vehicle on long downgrades without using the service brakes Correct answer.
  3. To lock the wheels during emergency stops
  4. To improve fuel mileage at high speed

Explanation

A retarder is an auxiliary braking device that helps slow the vehicle on long downgrades, reducing reliance on the service brakes and helping prevent brake fade. It does not replace the service brakes for stopping. It should be used according to the manufacturer's guidance, especially on slippery surfaces.

Question 23General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

You are following a motorcycle on a wet road. What should you do?

  1. Follow more closely to discourage others from cutting in
  2. Pass immediately on a curve
  3. Allow extra following distance because motorcycles can stop quickly Correct answer.
  4. Honk to make the rider speed up

Explanation

Motorcycles can stop in a shorter distance than a heavy truck, and wet roads lengthen your stopping distance further. Allow extra following distance so you have room to react if the rider slows suddenly. Following closely, passing on a curve, or honking creates hazards.

Question 24General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

What is the purpose of a pre-trip inspection?

  1. To satisfy paperwork only
  2. To find defects before they cause a breakdown or crash Correct answer.
  3. To check fuel prices
  4. To test the radio

Explanation

A pre-trip inspection is a systematic check of critical systems such as brakes, tires, lights, and coupling devices to catch defects before they cause a breakdown or crash. It also helps the driver understand the vehicle's condition. It is a safety requirement, not a formality.

Question 25General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

You are driving and a tire blows out at highway speed. What should you do?

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

Explanation

With a blowout, hold the steering wheel firmly to keep control, ease off the accelerator so the vehicle slows gradually, and pull off the road once you have slowed. Hard braking or sharp steering can cause a loss of control or a rollover. Accelerating makes the situation worse.

Question 26General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

Under Louisiana and federal rules, a commercial motor vehicle must be placed out of service when the driver's blood alcohol concentration reaches what level?

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

Explanation

A CDL holder is subject to a stricter standard than other drivers. A blood alcohol concentration of 0.04 percent or higher while operating a commercial motor vehicle results in the driver being placed out of service, and driving a CMV at 0.04 or above is also a criminal offense. The 0.08 threshold applies to non-commercial drivers.

Question 27General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

How soon after being convicted of a first offense of driving a CMV with a blood alcohol concentration of 0.04 percent or higher is a CDL disqualified?

  1. Only after a second offense within three years
  2. Only if the vehicle was involved in a crash
  3. After a hearing before the state licensing board
  4. Immediately upon conviction, for one year Correct answer.

Explanation

A first conviction for driving a CMV while impaired disqualifies the driver for one year, and the disqualification takes effect on the date of conviction. A second offense results in lifetime disqualification. No crash or hearing is required for the first-offense penalty.

Question 28General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

You must report to your employer, in writing, any traffic violation conviction (other than a parking violation) within how many days, regardless of the type of vehicle you were driving?

  1. 15 days
  2. 30 days Correct answer.
  3. 7 days
  4. 60 days

Explanation

A CDL holder must notify the employer in writing within 30 days of any conviction for a traffic violation other than a parking violation, even if the violation occurred in a personal vehicle. Failure to report can itself lead to loss of the CDL.

Question 29General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

When a driver is subject to a random controlled-substances test under federal rules, when is the test conducted?

  1. At any time while the driver is on duty, and just before or just after duty Correct answer.
  2. Only during the driver's scheduled shift
  3. Only when the driver volunteers
  4. Only after a crash involving injury

Explanation

Random testing must be spread throughout the year and conducted on an unannounced basis. A selected driver can be tested at any time while on duty and immediately before or after performing safety-sensitive functions.

Question 30General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

You are driving a loaded tractor-trailer and need to make a right turn at a tight intersection. Which technique best keeps the rear wheels from climbing the curb?

  1. Keep the tractor close to the right curb and turn from the outside lane
  2. Swing wide to the left before starting the turn
  3. Turn sharply and accelerate through the turn
  4. Slow down and begin the turn after the rear wheels clear the corner Correct answer.

Explanation

Large vehicles off-track, so the rear wheels follow a shorter path than the front wheels. Slowing before the turn and delaying the steering input until the rear wheels have passed the corner keeps them inside the curb line. Accelerating or turning early worsens off-tracking.

Question 31General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

On a two-lane road, when should you downshift before entering a curve?

  1. Only after you exit the curve
  2. Before entering the curve, so you can accelerate gently through it Correct answer.
  3. Never; coasting through the curve is preferred
  4. After entering the curve, once you feel the vehicle lean

Explanation

The correct sequence is to slow down to a safe speed before the curve, downshift while still traveling straight, and then accelerate gently through the curve. Shifting while turning can cause the vehicle to skid.

Question 32General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

You are driving a manual-transmission truck and must stop on an upgrade. Which action helps prevent the vehicle from rolling backward when you start again?

  1. Release the clutch quickly and add full throttle
  2. Shift into a higher gear before releasing the brake
  3. Use the parking brake or trailer brake to hold the vehicle until the clutch engages Correct answer.
  4. Hold the clutch partially engaged while the brakes are released

Explanation

On an upgrade, use the parking brake or trailer hand valve to hold the vehicle while you let out the clutch and apply power. Once you feel the clutch engage, release the brake and pull away. Slipping the clutch under load or starting in a high gear damages the drivetrain and risks a rollback.

Question 33General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

Which gear should you select when driving down a long, steep downgrade in a heavy vehicle?

  1. A gear lower than the one you would use to climb the same grade Correct answer.
  2. Neutral to let the brakes cool
  3. A gear higher than the climb gear to save fuel
  4. The highest gear available

Explanation

Select a gear low enough that engine braking holds the vehicle at a safe speed without continuous service-brake use. A common rule is to descend in a gear no higher than the one needed to climb the same grade. Neutral or high gears remove engine braking and overheat the service brakes.

Question 34General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

When you double-clutch while shifting a non-synchronized transmission, what is the correct sequence?

  1. Hold the clutch down through both gear changes
  2. Shift without using the clutch at all
  3. Press the clutch to neutral, release, press again, then shift into the new gear Correct answer.
  4. Press the clutch, shift, release, then press again in the new gear

Explanation

Double-clutching means pressing the clutch, moving the lever to neutral, releasing the clutch, pressing it again, and then engaging the next gear. This lets the input shaft speed match the gear so the teeth mesh without grinding.

Question 35General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

In a vehicle with a dual air-brake system, what happens when the pressure in one of the two systems drops to a low level?

  1. The trailer brakes apply and cannot be released
  2. Both systems lose all braking immediately
  3. The spring brakes release automatically
  4. The other system continues to provide braking, and a warning alerts you Correct answer.

Explanation

A dual air-brake system is split so that a failure in one circuit does not empty the other. If one system loses pressure, the other still provides braking, and a low-pressure warning alerts the driver. Both circuits are not lost at once.

Question 36General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

After you have fully charged the air system, you release the parking brake and then apply it again. What is the purpose of this check?

  1. It measures the compressor's build-up rate
  2. It confirms the spring brakes apply and release properly Correct answer.
  3. It verifies that the low-pressure warning buzzer works
  4. It tests the trailer light connection

Explanation

With the system charged, releasing and reapplying the parking brake confirms that the spring brakes release and then apply as pressure changes. This is a functional check of the parking-brake circuit, not a pressure-loss or warning test.

Question 37General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

What is the correct way to test the service brakes after the air system is fully charged?

  1. Pump the brake pedal repeatedly until the warning sounds
  2. Move forward slowly and apply the brakes firmly to check for pull or delay Correct answer.
  3. Release the parking brake and let the vehicle roll freely
  4. Hold the brake pedal down for five minutes and watch the gauge

Explanation

With normal pressure, move the vehicle slowly forward and apply the service brakes firmly. The vehicle should stop smoothly without pulling to one side, and the brakes should engage without noticeable delay.

Question 38General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

You are driving a loaded truck and the rear of your vehicle begins to fishtail on a slippery road. What is the safest response?

  1. Apply the brakes hard and hold the wheel straight
  2. Accelerate to pull the vehicle straight
  3. Turn the wheel sharply against the skid
  4. Release the accelerator and steer gently in the direction you want to go Correct answer.

Explanation

When the rear wheels lose traction, ease off the accelerator and steer smoothly in the direction you want the front of the vehicle to travel. Hard braking or sharp counter-steering can cause a spin.

Question 39General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

Why is it dangerous to use the engine brake (Jake brake) on a slippery road?

  1. It overheats the transmission fluid
  2. It disables the trailer brakes
  3. It increases fuel consumption sharply
  4. It can cause the drive wheels to lose traction and skid Correct answer.

Explanation

An engine brake applies retarding force only to the drive wheels. On wet, icy, or gravel surfaces this can break traction and cause a skid, so it should be switched off in slippery conditions.

Question 40General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

You are driving at highway speed when your right front tire suddenly blows out. What should you do?

  1. Brake hard immediately and steer to the shoulder
  2. Hold the wheel firmly, ease off the accelerator, and steer straight while slowing gradually Correct answer.
  3. Turn the wheel sharply toward the shoulder
  4. Accelerate to stabilize the vehicle

Explanation

A blowout causes a strong pull toward the failed tire. Grip the wheel firmly, keep the vehicle straight, and let it slow gradually before pulling off the road. Hard braking or sharp steering can cause a loss of control.

Question 41General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

When a school bus with its red lights flashing is stopped on a two-lane road, what must you do?

  1. Stop and remain stopped until the red lights stop flashing Correct answer.
  2. Slow to 15 mph and pass carefully
  3. Pass if the bus is on the opposite side of the road
  4. Stop only if children are visible

Explanation

On an undivided two-lane road, traffic in both directions must stop for a school bus with flashing red lights and remain stopped until the lights stop flashing. Passing is permitted only when the bus driver signals or the lights are off.

Question 42General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

When are you required to stop before a drawbridge?

  1. When a signal or attendant indicates a stop, or when the bridge is open Correct answer.
  2. Never; drawbridges are always passable
  3. Only at night
  4. Only when a train is approaching

Explanation

You must stop before a drawbridge when a signal or attendant tells you to stop, or when the bridge is open or being opened. Proceeding past a stop signal at a drawbridge is a serious violation.

Question 43General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

You are approaching a hill on a two-lane road and cannot see oncoming traffic. Which action is safest?

  1. Flash your headlights and continue
  2. Keep to your lane and reduce speed so you can stop within the visible distance Correct answer.
  3. Sound your horn and maintain speed
  4. Move to the left to get a better view

Explanation

When your view is blocked by a hill, you must be able to stop within the distance you can see. Keep to your lane and slow down so oncoming traffic is never a surprise. Crossing the centerline to see better puts you in the opposing lane.

Question 44General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

When entering a curve, what is the correct way to adjust your speed?

  1. Brake firmly in the middle of the curve
  2. Maintain a constant speed regardless of the curve
  3. Slow down before the curve, then accelerate gently through it Correct answer.
  4. Accelerate before the curve to increase traction

Explanation

Enter the curve at a safe speed and accelerate gently once you are through the first part of it. Braking while turning can cause a skid, and entering too fast leaves no margin for error.

Question 45General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

What is the proper way to use your horn when passing a bicyclist on a narrow road?

  1. Sound the horn continuously until you pass
  2. Sound a long blast to warn the cyclist
  3. Tap lightly only if needed, and pass with plenty of clearance Correct answer.
  4. Never use the horn under any circumstances

Explanation

A horn can startle a cyclist and cause a swerve. Use it only when necessary, and give the cyclist a safe clearance when passing. On a narrow road, wait until you can pass with adequate space.

Question 46General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

You are driving a truck with a high center of gravity and must make a sharp turn. What is the main hazard?

  1. The rear wheels may lock
  2. The trailer lights may fail
  3. The vehicle may roll over because of the high center of gravity Correct answer.
  4. The air pressure may drop suddenly

Explanation

A high center of gravity raises the rollover risk when you turn sharply or too fast. Reduce speed before the turn and avoid sudden steering inputs to keep the load from shifting sideways.

Question 47General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

When must you inspect your cargo during a trip?

  1. Once every 24 hours
  2. Within the first 50 miles and every 150 miles or three hours thereafter Correct answer.
  3. Only at the final destination
  4. Only before departure

Explanation

Federal rules require that cargo be inspected within the first 50 miles of a trip and again every 150 miles or three hours of driving, whichever comes first. The driver must also check cargo after any change in the load.

Question 48General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

A truck's cargo is loaded so that the weight is concentrated behind the rear axle. What is the main effect on handling?

  1. The front brakes engage more strongly
  2. The engine loses power
  3. The trailer lights fail
  4. The front axle is lightened, reducing steering control Correct answer.

Explanation

Loading too far back lightens the front axle, which reduces steering traction and makes the vehicle harder to control. It can also overload the rear axle and trailer. Weight must be distributed so each axle carries its rated load.

Question 49General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

You must stop on a narrow shoulder at night. Which action makes your vehicle most visible to other drivers?

  1. Leave the headlights on and turn on the four-way flashers Correct answer.
  2. Turn on the high beams
  3. Use only the parking lights
  4. Turn off all lights to avoid glare

Explanation

When stopped on or near the roadway at night, keep your headlights on and turn on the four-way flashers so approaching drivers can see you in time. High beams can blind oncoming traffic, and parking lights alone are too dim.

Question 50General Knowledge (vehicle inspection, basic control, shifting, seeing, communicating, speed and space management, emergency maneuvers, hazard awareness, railroad crossings, cargo, fatigue, alcohol and drugs)

You are driving a vehicle with a placarded load of hazardous materials and come to a railroad crossing. What must you do?

  1. Stop only if the crossing has gates
  2. Stop before the crossing, look and listen, and cross only when clear Correct answer.
  3. Sound the horn and cross without stopping
  4. Slow to 15 mph and proceed if no train is visible

Explanation

A vehicle carrying placarded hazardous materials must stop before every railroad crossing, look and listen, and proceed only when the track is clear. The stop is required even when no train is visible and regardless of gates.