Free South Carolina CDL Combination Practice Test 2025

Part of mandatory Entry-Level Driver Training Course Based on 2025 SC commercial driver's license manualAvailable in EN, ES

25questions

5mistakes allowed

80%passing score

In the United States, there are three classes of Commercial Driver Licenses (CDLs). A Class A CDL is typically for operating heavy combination vehicles, such as semi-trucks and tractor-trailers. A Class B CDL is typically for operating large single-unit vehicles, including large buses, box trucks, and most dump trucks. A Class C CDL is typically for operating smaller commercial vehicles that transport hazardous materials or at least 16 occupants (including the driver), such as small buses (including shuttle buses) or small trucks carrying hazardous materials.

To obtain a CDL of any class, you must meet a series of requirements. Notably, you must pass a medical examination and a General Knowledge test on commercial driving theory to obtain a Commercial Learner’s Permit (CLP). With a CLP, you can practice commercial driving under supervision until you become good enough at it to pass the official skills test, which includes basic vehicle maneuvers, a pre-trip inspection test, and a road test. Passing the skills test is a necessary and huge step toward obtaining a CDL.

However, depending on which class of CDL you’re applying for and which types of vehicles you plan to drive, you may have to pass certain additional knowledge tests. To be allowed to drive combination vehicles, you must pass the Combination Vehicles knowledge test.

This free South Carolina CDL Combination practice test is based on the official CDL manual (South Carolina CDL Handbook 2025), just like the official knowledge test. It’s up to date as of January 2025. There are 25 multiple-choice practice questions and answers on such topics as combination braking systems, combination driving techniques, coupling and uncoupling, and pre-trip inspections. Each question comes with an available hint to nudge you toward the correct answer, and an explanation of the correct answer. You can also ask our automated assistant for even more help. What this test doesn’t come with is a time limit. Take your time and learn the material addressed by this practice test.

Once you obtain a CDL of the appropriate class and the endorsements you need for the vehicles and cargoes you plan to drive, the world of commercial driving will open up for you. South Carolina’s agriculture, timber, and manufacturing industries rely on truckers to transport their products, often exported from the state. In addition, the Port of Charleston is one of the busiest container seaports on the East Coast. There are many kinds of truck operations there: dray (short distance), over-the-road (long distance), container transport, hazardous materials transport, and overdimensional (oversize) transport. Seaports, like airports, have secure areas. You may need to obtain a Transportation Worker Identification Credential (TWIC) card.

4.16 out of 5 • 25 votes.

Perfect for

First-time SC CDL and CLP applicants
CDL holders adding endorsements
SC CDL renewal applicants

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What to expect on the actual exam

How many questions	20
How many correct answers to pass	16
Passing score	80%

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List of questions (classic view)

After you lock the kingpin into the fifth wheel, how should you check the connection?
After you connect the air lines but before you back under the trailer, you should
Which statement best illustrates the "crack-the-whip" effect?
When you inspect the landing gear after uncoupling the trailer, where should the tractor be?
What is the safest way to turn right from a two-way road?
To drive a triple combination vehicle, you must have
To prevent a rollover, cargo should be
Combination vehicles take longer to stop when they are empty than when they are fully loaded, because
If your vehicle gets stuck on a railroad track, you should
Low-slung vehicles can be risky at railroad crossings because
On a double or triple vehicle, which wheels offtrack the most?
When you're pulling doubles or triples, the shut-off valves should always be
On a trailer, where is the yellow antilock brake (ABS) malfunction lamp located?
Even before antilock braking systems (ABS) were required, some vehicles already had them. How can you check if your vehicle has ABS?
An antilock braking system (ABS) is useful
After coupling, make sure that the air lines are not crossed. How should you do this?
During uncoupling, you should disconnect the electrical cable and
Before you start to uncouple, you must
You can confirm that air is going to all brakes in your trailers by
To uncouple a loaded trailer, after the landing gear has made firm contact with the ground, you should
If the trailer has antilock brakes (ABS) but the tractor doesn't,
To test the tractor protection valve, charge the trailer air brake system, turn off the engine, and
If your test of the tractor protection valve is successful,
The tractor protection valve is designed to close automatically if the air pressure falls into the pressure range specified by the manufacturer, typically
As part of your vehicle inspection test, if your vehicle is equipped with air brakes and has a trailer, you will inspect the air connections between the truck or tractor and the trailer. Make sure that the ________ are locked in place and free of damage or air leaks.