Free South Carolina CDL practice test online
Take a free South Carolina CDL practice exam online with clear explanations—no sign-up. Coverage includes general knowledge, vehicle systems, combination vehicles, cargo, and endorsements. Then verify current requirements with South Carolina Department of Motor Vehicles.
CDL knowledge tests are federally regulated, so the passing score in South Carolina is the same as everywhere else: 80% correct on every knowledge test. You must also hold a commercial learner’s permit for 14 days before the skills test.
New to the knowledge test? CDL endorsements explained · One-week study plan
Requirements before you test
South Carolina CDL test requirements
Commercial licensing is largely federal. Any figure above credited to a 49 CFR section applies in every state — see 49 CFR 383.135(a)(1) and 49 CFR 383.25(e). A figure credited to South Carolina Department of Motor Vehicles is South Carolina’s own, and may be stricter than the federal floor. Test length, fees, and scheduling are set by South Carolina Department of Motor Vehicles (official source).
Entry-Level Driver Training comes first
Since February 7, 2022, a new Class A or Class B CDL, a class upgrade, or a first passenger, school bus, or hazardous materials endorsement requires training from a provider on the FMCSA Training Provider Registry (49 CFR 380.600). Practice questions are study material and do not satisfy that requirement.
FMCSA Training Provider RegistryYou need a South Carolina licence first
A commercial learner’s permit only counts if you already hold an ordinary licence from the same state (49 CFR 383.25(a)(2)). The South Carolina non-commercial knowledge test runs 30 questions and needs 24 correct, with permits issued from age 15.
South Carolina permit practice testWhat you will practice
Build coverage topic by topic.
Each question carries a topic, difficulty, explanation, and source section so your review has context.
Sample questions
5 South Carolina CDL practice questions
Try these South Carolina sample questions now — each shows the correct answer with a plain-language explanation and a source section. The full 600-question bank is in the practice run.
1. If you double your speed from 20 to 40 mph, the impact (striking power) is about:
- ATwice as great
- BThree times as great
- Four times as great
- DThe same
Answer: Four times as great. Impact increases with the square of speed. Doubling speed multiplies striking power by about four.
Source: Commercial Driver License Manual — Driving safely — effect of speed
2. Uranium and plutonium shipments are Hazard Class:
- A1
- B5
- 7 (radioactive)
- D8
Answer: 7 (radioactive). Class 7 radioactive packages may show a transport index that limits how many can ride in one vehicle.
Source: Commercial Driver License Manual — Hazardous materials — hazard classes
3. Tail swing is the reason a school bus driver must check mirrors before:
- ATurning on the flashing lights
- BOpening the entrance door
- CApplying the parking brake
- Pulling away from a stop or curb
Answer: Pulling away from a stop or curb. The rear of the bus sweeps outward several feet as the front turns, which can strike a vehicle, pole, or person alongside.
Source: Commercial Driver License Manual — School buses — basic control
4. Spring brakes are held OFF by:
- AMechanical wedges only
- Air pressure in the brake chambers/spring brake chambers
- CHydraulic fluid only
- DElectric ABS solenoids alone
Answer: Air pressure in the brake chambers/spring brake chambers. When air pressure drops low enough, springs apply the brakes. That is why low-air warnings and leak tests matter.
Source: Commercial Driver License Manual — Air brakes — spring brakes
5. How often should a commercial driver check the mirrors in normal driving?
- Every 5 to 8 seconds
- BOnce every minute
- COnly before a lane change
- DOnly when a vehicle passes
Answer: Every 5 to 8 seconds. Regular checks show traffic entering your blind areas, tire problems, and cargo or door issues before they become emergencies.
Source: Commercial Driver License Manual — Seeing — mirror use
CDL knowledge areas
Classes and endorsements, organized.
Each area below scopes the reviewed question bank to one knowledge test. The material is federal, so it applies in South Carolina just like everywhere else — the endorsement guide explains how the codes fit together.
The foundation for commercial driving: inspections, space, speed, communication, hazards, and safe operation.
- Pre-trip inspection
- Space and speed management
- Railroad crossings
- Emergency procedures
Understand air-brake components, inspections, warning devices, stopping distance, and controlled braking.
- Dual air systems
- Low-air warnings
- Brake lag and fade
- Applied-leak and static checks
Prepare for safe coupling, inspection, turning, backing, and handling of tractor-trailer combinations.
- Fifth-wheel inspection
- Coupling and uncoupling
- Off-tracking
- Trailer skid prevention
Study hazard communication, shipping papers, placards, loading rules, parking, and emergency response responsibilities.
- Hazard classes
- Placards and labels
- Shipping papers
- Loading and segregation
Learn how liquid surge, outage, bulkheads, and high centers of gravity change vehicle handling.
- Liquid surge
- Outage requirements
- Smooth braking
- Rollover prevention
Practice converter-dolly inspection, coupling order, rearward amplification, and stability principles.
- Coupling sequence
- Converter dollies
- Rearward amplification
- Space management
Prepare to inspect, load, and operate buses while keeping passengers, aisles, and exits safe.
- Vehicle inspection
- Passenger loading
- Emergency exits
- Prohibited practices
Review student loading, danger zones, mirrors, emergency procedures, and special railroad-crossing duties.
- Danger zones
- Student loading
- Mirror use
- Railroad crossings
More south practice
Nearby CDL practice tests
Jump to another south state hub, or browse every jurisdiction.
Common questions
What this practice can—and cannot—tell you.