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.
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How can you check if your vehicle has ABS?
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To uncouple a loaded trailer, after the landing gear has made firm contact with the ground, you should
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If your test of the tractor protection valve is successful,
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After coupling, how should you make sure that the air lines are not crossed?
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To test the tractor protection valve, charge the trailer air brake system, turn off the engine, and
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When you're pulling doubles or triples, the shut-off valves should always be
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To prevent a rollover, cargo should be
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As part of your vehicle inspection test, make sure that the ________ are locked in place and free of damage or air leaks.
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When you inspect the landing gear after uncoupling the trailer, where should the tractor be?
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What is the safest way to turn right from a two-way road?
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On a double or triple vehicle, which wheels offtrack the most?
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To drive a triple combination vehicle, you must have
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If your vehicle gets stuck on a railroad track, you should
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Before you start to uncouple, you must
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Which statement best illustrates the 'crack-the-whip' effect?
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Low-slung vehicles can be risky at railroad crossings because
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If the trailer has antilock brakes (ABS) but the tractor doesn't,
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During uncoupling, you should disconnect the electrical cable and
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After you lock the kingpin into the fifth wheel, how should you check the connection?
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You can confirm that air is going to all brakes in your trailers by
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After you connect the air lines but before you back under the trailer, you should
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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.