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300+ Free SC CDL General Knowledge Practice Questions

Pass your South Carolina CDL General Knowledge Test exam on the first try — instant access, no signup required.

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2026 Statistics

Key Facts: SC CDL General Knowledge Exam

80%

Passing Score

49 CFR 383.135 / FMCSA States page

30+

Minimum Basic Knowledge-Test Items

FMCSA States page

$2

SCDMV Knowledge-Test Fee

SCDMV Fees

14 days

Minimum CLP Hold Before Skills Test

SCDMV CDL Testing / Getting Your First CDL

4:00 p.m.

SCDMV Knowledge-Test Cutoff

SCDMV CDL Testing

South Carolina requires the CDL General Knowledge test for all CDL applicants. FMCSA requires basic knowledge tests to include at least 30 items, cover the 20 general knowledge areas in 49 CFR 383.111(a), and use an 80% passing standard. SCDMV charges $2 per knowledge test, plus CLP application and permit fees for first-time applicants.

Sample SC CDL General Knowledge Practice Questions

Try these sample questions to test your SC CDL General Knowledge exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 300+ question experience with AI tutoring.

1What is the first step in the seven-step pre-trip inspection method?
A.Approach the vehicle and check its general condition
B.Check under the hood
C.Start the engine and inspect inside the cab
D.Walk around and inspect the entire vehicle
Explanation: The first step of the seven-step pre-trip inspection is to approach the vehicle and look at its general condition. This includes checking for damage, whether the vehicle is leaning to one side, and looking under the vehicle for fresh leaks of oil, coolant, grease, or fuel. This initial overview can immediately reveal serious problems before you invest time in a detailed inspection.
2During a pre-trip inspection, what should you check in the engine compartment?
A.Only the oil level
B.Oil level, coolant level, power steering fluid, belts, and hoses
C.Only the coolant level and belts
D.Only items visible without opening any caps
Explanation: A thorough engine compartment inspection includes checking the oil level, coolant level in the radiator, power steering fluid, condition of belts and hoses for wear or cracks, and looking for leaks. You should also check the alternator, water pump, air compressor, and any other belt-driven components. Checking only one or two items could mean missing a critical problem that leads to a breakdown or safety hazard on the road.
3When performing a pre-trip inspection, the driver should ensure that the steering wheel free play (lash) does not exceed what limit?
A.5 degrees in either direction
B.10 degrees in either direction (approximately 2 inches on a 20-inch wheel)
C.15 degrees in either direction
D.20 degrees in either direction
Explanation: Federal Motor Carrier Safety Regulations require that steering wheel free play (lash) not exceed 10 degrees in either direction, which translates to roughly 2 inches of movement on a 20-inch diameter steering wheel before the front wheels begin to turn. Excessive free play indicates worn steering components and can make precise steering difficult, especially in emergency maneuvers. A vehicle with excessive steering lash would be placed out of service.
4During the cab check portion of a pre-trip inspection, you should test the parking brake by:
A.Driving forward slowly and applying the parking brake
B.Putting the vehicle in gear with the parking brake set and gently pressing the accelerator to see if the vehicle holds
C.Visually checking that the parking brake handle is in the correct position
D.Checking the parking brake cable under the vehicle
Explanation: To properly test the parking brake, set the parking brake, put the vehicle in a low gear, and gently press the accelerator to see if the brake holds the vehicle in place. This functional test confirms the parking brake can actually prevent the vehicle from moving, which is essential for safety when parked on grades. A visual check alone is insufficient because it does not verify that the brake mechanism is actually functioning properly.
5Which emergency equipment is required to be on a commercial motor vehicle?
A.Fire extinguisher, spare fuses, and three red reflective triangles
B.First aid kit, fire extinguisher, and flares only
C.Fire extinguisher and road flares only
D.Spare tire, jack, and reflective vest
Explanation: Federal regulations require every commercial motor vehicle to carry a properly charged and rated fire extinguisher (minimum 5 B:C rating, or two 4 B:C extinguishers), spare electrical fuses (unless the vehicle has circuit breakers), and three red reflective warning triangles (or equivalent). These items are checked during inspections and roadside enforcement stops. A vehicle missing any of these required items can be cited for a violation.
6A post-trip inspection report is important because:
A.It is only required for vehicles carrying hazardous materials
B.It alerts the carrier to vehicle defects that may need repair before the vehicle is driven again
C.It replaces the need for the next driver to do a pre-trip inspection
D.It is optional but recommended by the FMCSA
Explanation: The post-trip inspection report (also called a DVIR, or Driver Vehicle Inspection Report) is required by FMCSA regulations (49 CFR 396.11). Its purpose is to document any defects or deficiencies discovered at the end of the trip so the carrier can arrange repairs before the vehicle is dispatched again. The next driver must review the previous post-trip report and verify that any noted defects have been repaired or certified as not needing repair. It does not replace the next driver's pre-trip inspection obligation.
7During a pre-trip inspection, the driver notices a coolant leak near the water pump. What should the driver do?
A.Note it on the report and drive carefully to the next service stop
B.Add more coolant and continue the trip
C.Do not drive the vehicle until the leak is repaired
D.Drive only short distances and monitor the temperature gauge
Explanation: A coolant leak is a serious defect that can lead to engine overheating and catastrophic engine failure. The vehicle should not be driven until the leak is repaired. Driving with a coolant leak risks engine damage, potential fire (if coolant contacts hot exhaust components), and could result in a roadside breakdown in an unsafe location. FMCSA regulations require that defects affecting safe operation be corrected before the vehicle is driven.
8Which of the following is an out-of-service condition that would prevent a vehicle from being driven?
A.A small crack in the windshield that does not obstruct the driver's view
B.A missing mud flap on a rear wheel
C.Brake lining thickness below the minimum allowed by regulations
D.A broken antenna on the CB radio
Explanation: Brake lining worn below the minimum thickness specified in FMCSA out-of-service criteria is a critical safety defect. The North American Standard Out-of-Service Criteria lists specific thresholds: brake lining must not be less than 1/4 inch thick at the thinnest point for air-braked vehicles. When brake linings are too thin, braking effectiveness is severely compromised, and the vehicle must be placed out of service until repairs are made. A small windshield crack not in the driver's view, a missing mud flap, or a broken CB antenna are defects but not typically out-of-service conditions.
9During the pre-trip inspection, which of the following should a driver check regarding the exhaust system?
A.Only that the muffler is present
B.That the exhaust system is secure, not leaking, and not in contact with fuel lines, wiring, or air lines
C.Only that exhaust fumes are not entering the cab
D.That the catalytic converter is functioning properly by checking emissions color
Explanation: When inspecting the exhaust system, the driver should verify that all components are properly mounted and secured, there are no leaks (which could allow poisonous carbon monoxide to enter the cab), and the exhaust system is not in contact with fuel supply lines, wiring, or air brake lines. Heat from the exhaust can damage these components, potentially causing fuel leaks, electrical fires, or brake failures. A complete exhaust system inspection goes beyond just checking for the presence of a muffler.
10What is the minimum tread depth required for steer axle tires on a commercial motor vehicle?
A.2/32 of an inch
B.4/32 of an inch
C.6/32 of an inch
D.1/32 of an inch
Explanation: Federal regulations require steer axle tires to have a minimum tread depth of 4/32 of an inch (approximately 3.2 mm) in every major groove. Steer tires have a higher minimum than other axle positions (which require only 2/32 of an inch) because the steer tires are critical for directional control of the vehicle. Tires below this minimum are considered unsafe and will result in a violation or out-of-service order during an inspection.

About the SC CDL General Knowledge Exam

South Carolina CDL General Knowledge practice for CLP applicants covering the SCDMV manual, FMCSA general knowledge areas, safe driving, inspections, cargo, and CDL basics.

Assessment

FMCSA requires each basic CDL knowledge test to contain at least 30 items and cover the 20 general knowledge areas in 49 CFR 383.111(a). South Carolina requires General Knowledge for all CDL applicants.

Time Limit

SCDMV does not publish a fixed time limit; knowledge testing is not allowed after 4:00 p.m.

Passing Score

80%

Exam Fee

$2 per knowledge test, plus $15 CDL application fee and $2.50 CLP fee for an initial CLP application (South Carolina Department of Motor Vehicles (SCDMV) under FMCSA CDL standards)

SC CDL General Knowledge Exam Content Outline

20%

Vehicle Inspection and Control Systems

Pre-trip, en route, and post-trip inspections; fluid leaks, steering, suspension, tires, wheels, brakes, lights, mirrors, emergency equipment, and defect reporting.

20%

Basic Control, Shifting, Speed, and Space

Starting, stopping, backing, turning, off-tracking, shifting, following distance, braking distance, curves, ramps, grades, and overhead clearance.

15%

Seeing, Communication, and Hazard Perception

Scanning, mirror use, signaling, traffic conflicts, railroad crossings, work zones, pedestrians, cyclists, and defensive response to aggressive or distracted road users.

20%

Adverse Conditions, Emergencies, and Skid Recovery

Night driving, fog, rain, snow, ice, hot weather, mountain driving, brake failure, tire blowouts, off-road recovery, fires, emergency stops, and skid control.

15%

Cargo, Weight, and Securement

Cargo inspection timing, tie-down requirements, blocking and bracing, tarps, working load limits, weight distribution, axle limits, and bridge formula basics.

10%

Driver Wellness and South Carolina CDL Rules

Fatigue, alcohol/drug testing, CDL disqualifications, medical certification, South Carolina CLP requirements, fees, ELDT, and SCDMV testing logistics.

How to Pass the SC CDL General Knowledge Exam

What You Need to Know

  • Passing score: 80%
  • Assessment: FMCSA requires each basic CDL knowledge test to contain at least 30 items and cover the 20 general knowledge areas in 49 CFR 383.111(a). South Carolina requires General Knowledge for all CDL applicants.
  • Time limit: SCDMV does not publish a fixed time limit; knowledge testing is not allowed after 4:00 p.m.
  • Exam fee: $2 per knowledge test, plus $15 CDL application fee and $2.50 CLP fee for an initial CLP application

Keys to Passing

  • Complete 500+ practice questions
  • Score 80%+ consistently before scheduling
  • Focus on highest-weighted sections
  • Use our AI tutor for tough concepts

SC CDL General Knowledge Study Tips from Top Performers

1Use the South Carolina Commercial Driver License Manual as the primary study source before taking any SCDMV knowledge test.
2Start with inspection defects and control systems because 49 CFR 383.111 explicitly includes vehicle inspection and safety-control knowledge.
3Practice following-distance, stopping-distance, turning, backing, and railroad-crossing scenarios until the safe action is automatic.
4Review night, fog, rain, snow, ice, hot weather, mountain driving, skids, blowouts, and brake-failure procedures as separate hazard groups.
5Memorize cargo inspection intervals, securement principles, axle-weight concepts, and how shifting cargo affects vehicle control.
6Know South Carolina logistics: General Knowledge is required for all CDL applicants, tests are at SCDMV branches, and knowledge testing stops after 4:00 p.m.
7Confirm whether you need additional tests such as air brakes, combination vehicles, tanker, passenger, school bus, hazmat, or doubles/triples before visiting SCDMV.
8Plan CLP timing around the 14-day minimum holding period and ELDT requirements before scheduling a skills test.

Frequently Asked Questions

Who must take the South Carolina CDL General Knowledge test?

SCDMV lists General Knowledge as required for all CDL applicants. Additional knowledge tests depend on the vehicle class, air brakes, and endorsements needed.

What score do I need to pass?

FMCSA requires applicants to answer at least 80% of each CDL knowledge test correctly. This applies to general and endorsement knowledge tests.

How many questions are on the official test?

FMCSA states each basic knowledge test must contain at least 30 items. South Carolina uses CDL knowledge tests through SCDMV that must meet federal standards.

Where do I take the SC CDL knowledge test?

SCDMV says CDL knowledge tests may be taken at any SCDMV branch, and customers are not allowed to test after 4:00 p.m.

What does it cost to start with a South Carolina CLP?

SCDMV lists a $15 CDL application fee, $2 for each knowledge test, and $2.50 for the CLP, which has a one-year expiration date.

When can I take the CDL skills test after getting a CLP?

SCDMV requires at least 14 days from issuance of the original CLP before skills testing, and applicable FMCSA-approved ELDT must be completed before the skills test for covered applicants.