SC CDL Permit Practice Flashcards

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Questions and Answers

On a trailer, where is the yellow antilock brake (ABS) malfunction lamp located?

On the left front or left rear corner

Combination vehicles take longer to stop when they are empty than when they are fully loaded, because

there is less traction

The tractor protection valve is designed to close automatically if the air pressure falls into the pressure range specified by the manufacturer, typically

20 to 45 psi

An antilock braking system (ABS) is only useful on tractors.

False Signup and view all the answers

How can you check if your vehicle has ABS?

Look under the vehicle for the electronic control unit (ECU) and wheel speed sensor wires coming from the back of the brakes Signup and view all the answers

To uncouple a loaded trailer, after the landing gear has made firm contact with the ground, you should

turn the crank a few more times to lift some weight off the tractor Signup and view all the answers

If your test of the tractor protection valve is successful,

the tractor protection valve control (trailer air supply control) will pop out or go from 'normal' to 'emergency' Signup and view all the answers

After coupling, how should you make sure that the air lines are not crossed?

Adjust the air supply knob to send air to the trailer brakes. Turn off the engine once the air pressure normalizes. Then listen to the sound of escaping air as the brakes are released. Signup and view all the answers

To test the tractor protection valve, charge the trailer air brake system, turn off the engine, and

step on and off the brake pedal several times Signup and view all the answers

When you're pulling doubles or triples, the shut-off valves should always be

open except for those on the last trailer Signup and view all the answers

To prevent a rollover, cargo should be

spread evenly across the rig and as low as possible Signup and view all the answers

As part of your vehicle inspection test, make sure that the ________ are locked in place and free of damage or air leaks.

glad hands Signup and view all the answers

When you inspect the landing gear after uncoupling the trailer, where should the tractor be?

With the tractor frame under the trailer Signup and view all the answers

What is the safest way to turn right from a two-way road?

Turn wide as you complete the turn Signup and view all the answers

On a double or triple vehicle, which wheels offtrack the most?

The rear wheels of the last trailer Signup and view all the answers

To drive a triple combination vehicle, you must have

a Class A CDL with a Doubles/Triples (T) endorsement Signup and view all the answers

If your vehicle gets stuck on a railroad track, you should

get away from your vehicle and call 911 or the posted emergency number Signup and view all the answers

Before you start to uncouple, you must

make sure the ground is solid and can support the weight of the trailer Signup and view all the answers

Which statement best illustrates the 'crack-the-whip' effect?

If you make a quick lane change or sudden movement of your steering wheel, your trailers will tend to swing out. The rearmost trailer will swing out the most and will be most likely to roll over. Signup and view all the answers

Low-slung vehicles can be risky at railroad crossings because

they are more likely to get stuck on raised railroad crossings Signup and view all the answers

If the trailer has antilock brakes (ABS) but the tractor doesn't,

the trailer is less likely to swing out Signup and view all the answers

During uncoupling, you should disconnect the electrical cable and

hang it with the plug down Signup and view all the answers

After you lock the kingpin into the fifth wheel, how should you check the connection?

Pull the tractor ahead gently with the trailer brakes locked Signup and view all the answers

You can confirm that air is going to all brakes in your trailers by

opening the emergency line shut-off valve and then the service line valve at the rear of the last trailer and listening for air escaping each time Signup and view all the answers

After you connect the air lines but before you back under the trailer, you should

supply air to the trailer system and then pull out the air supply knob Signup and view all the answers

Study Notes

Antilock Braking System (ABS)

The yellow ABS malfunction lamp on trailers is found on the left front or left rear corner.
ABS is beneficial whether installed on tractors or trailers.
To check for ABS on a vehicle, look for the electronic control unit and wheel speed sensor wires near the brakes.

Tractor Protection Valve

The tractor protection valve automatically closes when air pressure drops, typically between 20 to 45 psi.
A successful test of the tractor protection valve will cause the control to switch from "normal" to "emergency."

Coupling and Uncoupling Procedures

After landing gear is down, crank it a few more times to relieve weight from the tractor before uncoupling a loaded trailer.
Ensure that the air lines are not crossed after coupling by adjusting the air supply knob and listening for air escaping from the brakes.
Prior to uncoupling, ensure the ground is solid enough to support the trailer’s weight.

Vehicle Inspection and Safety

Inspect air connections (glad hands) during vehicle checks to ensure they are locked and free from damage or leaks.
When inspecting landing gear post-uncoupling, the tractor should remain under the trailer frame.

Driving and Maneuvering Techniques

When making a right turn from a two-way road, remember to turn wide for safety.
In double or triple vehicle configurations, rear wheels of the last trailer are more prone to offtracking.
The "crack-the-whip" effect occurs during sudden lane changes, causing trailers to swing out, especially the rear most.

CDL Licensing and Regulations

Operating a triple combination vehicle requires a Class A CDL with a Doubles/Triples (T) endorsement.
Low-slung vehicles pose risks at railroad crossings due to a higher likelihood of getting stuck.

Emergency Procedures

If trapped on a railroad track, evacuate the vehicle immediately and contact emergency services.
If the trailer is equipped with ABS but the tractor is not, the risk of swinging out is reduced.

Electrical and Air Line Connections

Disconnect the electrical cable during uncoupling and let it hang plug down.
Ensure air is reaching all trailer brakes by opening shut-off valves and listening for air leaks at the end of the last trailer.
After connecting air lines, supply air to the trailer system and pull out the air supply knob before backing under the trailer.

General Cargo Safety

To prevent vehicle rollover, distribute cargo evenly and keep it as low as possible.

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Description

Test your knowledge with these flashcards designed for the South Carolina CDL Permit exam. Each card presents crucial information about vehicle safety features and handling characteristics. Perfect for aspiring commercial drivers looking to reinforce their understanding of regulations and vehicle mechanics.