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South Carolina CDL DMV Knowledge Test Class A 1

Take 6 practice tests for CDL is the best way to prepare for your South Carolina DMV exam is by taking our free practice tests. The following question are from real South Carolina DMV practice test. More than 95% people pass a DMV exam when practice at DMV Practice Test.

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1. Header boards:
Should never be used.
Protect drivers from being hit by cargo.
Protect drivers' heads when they are entering the cab of a truck.

A header board protects a driver from moving cargo in the event of a crash or emergency stop.

2. If an aggressive driver is involved in a crash down the road, you should:
Pull over and yell at them.
Stop after the crash scene and report the other driver’s behavior to police.
Block the driver in with your vehicle.

If you observe a crash involving an aggressive driver, you should stop a safe distance from the crash scene, wait for police to arrive, and inform them of the aggressive behavior you witnessed.

3. When inspecting underneath your vehicle for leaking fluids, you must look for all the following, except:
Fresh oil.
Windshield wiper fluid.

When approaching your vehicle before a trip, be sure to look underneath the vehicle for fresh oil, coolant, grease, or fuel leaks.

4. Headlights:
Are not usually necessary when driving at night.
Provide better light than the sun.
Should be on the high beam setting whenever possible.
Should always be on the high beam setting.

To improve visibility, you should use high beam headlights at night where it is safe and legal to do so. However, the glare from high beam lights can blind other drivers. You should dim your lights to their low beam setting when driving within 500 feet of an approaching vehicle.

5. In extremely hot conditions, you may have to:
Increase your speed to cool the engine.
Reduce your speed to prevent overheating.
Drain the engine coolant.
Follow other vehicles more closely than normal.

Faster speeds create more heat in the engine and tires, so slow down to avoid dangerous overheating when the weather is very hot.

6. Which of the following may result in an applicant being denied a hazardous materials endorsement?
They are considered a security threat by the Transportation Security Administration (TSA).
They are a lawful U.S. citizen.
They work for a foreign company.
They do not have perfect vision.

You will be denied a hazardous materials endorsement, or lose an existing endorsement, if you renounce your U.S. citizenship; are not a lawful permanent U.S. resident; are wanted for, indicted for, or convicted of certain felonies; are judged mentally defective or are committed to a mental institution; or are deemed by the Transportation Security Administration (TSA) to pose a security threat.

7. When traveling down a steep downgrade:
The air brakes should be used.
The vehicle should be placed in a low gear and the driver should use engine braking.
The driver should continually downshift instead of using the brakes.

On long and/or steep downgrades, you should primarily use engine braking to control the speed of your vehicle. Use your brakes only as a supplement to this effect.

8. Backing with a trailer is dangerous because:
It is difficult to see behind the vehicle.
Most trucks do not have the ability to go in reverse.
Cargo may fall out of the trailer.

Backing up is always dangerous because it is impossible to see everything that is behind you. Only drive in reverse if it is absolutely necessary.

9. Hydraulic brakes can fail due to:
A loss of pressure.
Cold weather.
Driving uphill for long periods of time.
Grooves in the roadway.

Failure of hydraulic brakes is often caused by a loss of hydraulic pressure. Hydraulic brakes may also fade because of overuse on a long downgrade.

10. When conducting a check of the engine compartment during a vehicle inspection, you should not:
Check the engine oil level.
Check the coolant level.
Drain the brake fluid.

When inspecting the engine compartment, you should check the oil level, coolant level, and windshield washer fluid level, among other things.

11. When driving at night, you should do all of the following, except:
Make sure you are rested.
Make sure your glasses are clean.
Wear sunglasses.

To ensure that you can see as well as possible, don't wear sunglasses when driving at night. If you wear eyeglasses, make sure they are clean and unscratched. Make sure you are rested and alert before driving at night.

12. Laws about securing loads and regulating CMV weights may vary from state to state. During interstate travel:
The law of the state in which the trip originated takes precedence.
The law of the state the vehicle is in takes precedence.
The driver should request federal regulations to override conflicting state laws.
The driver can choose which state’s laws to follow.

Commercial vehicle weight, securement of cargo, covering of loads, and where large vehicles can be driven are all regulated by federal, state, and local laws. These vary from place to place, so you must be aware of the rules that apply where you will be driving. State laws in the state in which you are driving take precedence.

13. Using the brakes creates heat. If too much heat is produced:
The brakes may not work.
The brakes may squeak more than usual.
The brakes will brake unevenly.

Brakes are designed to take a lot of heat, but drivers should not rely solely on the brakes to slow their vehicle. Brakes may fade and lose their ability to slow down the vehicle if they become too hot, so drivers should also rely on the engine braking effect.

14. If taking the driving test and the route does not include a railroad crossing, you:
Will not have to do anything related to a crossing.
May have to explain how you would cross railroad tracks.
Will have to take the test again on a route that does include a railroad crossing.

If your on-road driving test route does not include a railroad crossing, you may be asked to explain and demonstrate the proper railroad crossing procedures to the examiner at a simulated location.

15. How long is a CDL valid?
One year
Two years
Four years
Five years

In South Carolina, CDLs are valid for five years from the date of issuance.

16. An Anti-Lock Braking System (ABS):
Is not available for vehicles with air brakes.
Is not helpful in most driving situations.
Can help you maintain control when braking.

Anti-Lock Braking Systems (ABS) are compatible with air brakes and help a driver maintain control of their vehicle by preventing wheel lockup.

17. How is the parking brake released?
By tapping on the brake pedal three times
By pushing in the brake control knob
By engaging the accelerator
By tapping the accelerator twice

In newer vehicles with air brakes, the parking brakes are controlled by a diamond-shaped yellow knob. Pull the knob out to activate the parking brakes and push it in to release them.

18. Areas of the road that are shaded:
Usually do not freeze.
Usually do not contain moisture, so they can’t freeze.
Will remain slick after ice on other areas of the road has melted.
Should always be avoided.

Because they are exposed to less sunlight, shaded patches of road will stay cooler longer than other areas of the road. Due to the lack of direct sunlight, shady areas can remain icy and slippery after ice on other areas of the road has melted.

19. When the brake pedal is pushed down, air brakes work:
After a short delay.
After about a minute.
Only if it is warm outside.

Because air takes time to flow through the air lines to the brakes, air brakes cannot begin working instantly. There is often a brake lag of at least one-half of a second between the moment the brake pedal is pressed and the moment the brakes begin to work.

20. Driving with a cargo of hanging meat in a trailer:
Is discouraged during the summer months.
Can be problematic because animals are attracted to the smell of the meat.
Is challenging because the load has a high center of gravity.

An operator should drive with care when transporting a cargo of hanging meat. Such a load is unstable, both because it has a high center of gravity and because the swinging of the meat can affect the driver's handling of the vehicle.

21. Of the following, which is the most slippery surface?
Ice that is dry
Ice that is wet
Wet pavement

Ice becomes wet when the weather is just warm enough to melt the ice slightly. Wet ice is much more slippery than ice that is not wet.

22. When parked on the side of the road, you should:
Use only the rear flashing lights.
Use one set of turn signals.
Use your high beam headlights.
Use your four-way flashers.

Always turn on your four-way emergency flashers if you must park on the side of the road. This is especially important when traveling at night.

23. Emergency equipment in a vehicle is:
Only required for vehicles that are transporting hazardous materials.
Only required during interstate travel.

During a pre-trip inspection, you should check for emergency equipment, including spare electrical fuses; three red reflective triangles, six fuses, or three liquid burning flares; and at least one properly charged and rated fire extinguisher.

24. If a load is 40 feet long, the minimum number of tie-downs required to secure the load is:
Two tie-downs.
Three tie-downs.
Four tie-downs.

On flatbed trailers and trailers without sides, cargo must be tied down. There should be at least one tie-down for every 10 feet of cargo. Regardless of the size of the cargo, at least two tie-downs must be used.

25. Dry bulk tanks require special care because:
They have low centers of gravity.
They have high centers of gravity.
Loads are usually stable.
They are usually overloaded.

Driving with a dry bulk tank requires special care, both because dry bulk tanks have high centers of gravity and because their loads often shift in transit. Be especially careful when taking turns and curves while operating such a vehicle.

26. If you must leave the roadway and drive on the shoulder in an emergency situation, you should:
Brake as hard as possible.
Get both sets of wheels onto the shoulder.
Stay on the shoulder until your vehicle has stopped, if possible.

If you must drive onto the shoulder to avoid a hazard, stay on it until you come to a stop; then signal, check your mirrors, and merge back into traffic. Avoid braking on the shoulder at speeds higher than about 20 mph. To help maintain control, always keep one set of wheels on the pavement, if possible.

27. States verify that a CDL or CLP driver has only one such license by:
Making phone calls to surrounding states.
Using a computerized system that links all states.
Asking the driver.
Looking through the driver's wallet.

All U.S. states share information about CDL and CLP licenses in a computerized database. If you apply for a license in one state, a state will check this database to verify that you do not already have one such license in another state.

28. Where can you find the tire load rating?
On the inside of the driver’s door
On the dashboard
On the side of each tire
Under the hood

A tire load rating is the maximum safe weight that can be carried by a tire at a specified pressure. This number is stated on the side of each tire.

29. Which of the following is not a sign of a driver becoming tired?
Frequent blinking
Drifting from their lane
Feeling hungry

Potential warning signs of fatigued driving include difficulty focusing; frequent blinking or heavy eyelids; yawning repeatedly or rubbing one's eyes; daydreaming; wandering or disconnected thinking; trouble remembering the last few miles driven; missing exits or traffic signs; having trouble keeping one's head up; drifting from one's lane; following a vehicle too closely; hitting a shoulder rumble strip; and feeling restless or irritable.

30. Applying the brake pedal causes air pressure to activate an electric switch and:
Turn off the brake lights.
Turn on the low pressure warning light.
Turn on the brake lights.
Turn off the low pressure warning light.

In a vehicle with air brakes, the brake lights are activated when the brake pedal is pushed and air pressure moves an electric switch. With the application of air pressure, the switch will then turn on the brake lights.

31. Convex mirrors:
Cannot be used on vehicles transporting hazardous materials.
Are illegal in most states.
Can help drivers see a larger area.

Many large vehicles have curved, convex mirrors. Convex mirrors allow drivers to see a wider area than flat mirrors. However, they also make objects seem smaller and farther away than they really are.

32. A stopped bus:
Is not a cause for concern.
Is not a concern if passengers are not unloading.
Should not be on the roadway.
Is a concern, whether passengers are visible or not.

Always drive cautiously around a stopped bus. Passengers may cross in front of or behind it, and the bus may prevent them from seeing your vehicle.

33. What must be done if a load is over-length?
A warning flag must be placed on the end of the load.
The load may only be transported between 6 p.m. and 3 a.m.
The load must be shortened.
The emergency flashers must be activated.

Special equipment, such as warning flags or flashing lights, may be required if you are transporting an over-length load. When transporting such a a load, you will need to acquire the necessary permits. Driving is often limited to certain times.

34. Which of the following is not an indication of damaged brakes?
Cracked drums
Shoes with oil or grease on them
Shoes worn thinly
Pads free of oil or grease

Potential problems to check for when inspecting brakes include cracked drums; shoes or pads with oil, grease, or brake fluid on them; and shoes that are missing, broken, or worn dangerously thin.

35. Having weight loaded in a way that creates a high center of gravity:
Increases the likelihood of a rollover.
Increases the likelihood that items will fall down.
Increases the difficulty of unloading the cargo.

Transporting cargo that is loaded with a high center of gravity increases the risk that the transporting vehicle will tip over. Cargo should be loaded with a safe weight distribution.

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