South Carolina CDL Class B Practice Test (SC) 3

4.9 out of 5 (101 votes)
80% Passing score
20 Questions
4 Mistakes allowed
As a South Carolinian aspiring to earn a Class B CDL, you're in the right place. Our third CDL practice test is specifically tailored for your state's requirements in 2026, ensuring you get the most relevant and accurate preparation. With 20 carefully crafted DMV test questions and answers, this test is designed to challenge and enhance your understanding of critical CDL topics. A passing mark is set at 80%, requiring at least 16 correct answers. What sets our SC CDL class B practice test apart is its professional backing. Developed by seasoned driving instructors with years of experience, these sample written permit test questions are not just theoretical; they're based on real-world scenarios. Our team of experts, who have helped thousands earn their licenses, ensure the CDL questions and answers are up-to-date, covering everything from pre-trip vehicle inspection to handling steep downgrades. Remember, while this South Carolina DMV practice test is an invaluable tool, it complements rather than replaces traditional drivers education and ELDT programs. In South Carolina and elsewhere, completing a state-certified Entry-level Driver Training course is often mandatory. Our SC CDL practice test fills in any gaps, reinforcing your knowledge and ensuring you're not just prepared, but confident when you sit for your actual DMV written test in 2026. One of the biggest advantages of our South Carolina DMV class B practice test is the stress-free learning environment it offers. Unlike the pressure-filled atmosphere of the actual DMV CDL permit test, here you can learn at your own pace, revisit questions, and truly absorb the information. And the best part? The questions remain the same each time you take this online DMV practice test, allowing you to measure your progress accurately. So, gear up to enhance your CDL knowledge with our South Carolina CDL Class B Practice Test. It's more than just a test; it's a step towards securing your future on the road in 2026!
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Sample South Carolina CDL Test Questions - General Knowledge

Question 1

The same loading and unloading procedure may be used for every type of hazardous material.

  1. A True
  2. B False

Correct answer: B – False

Federal hazardous materials rules include general loading requirements as well as requirements that apply to particular hazard classes and forms of packaging. For example, certain flammable, explosive, oxidizing, and gaseous materials are subject to specific precautions. Drivers must identify the material and follow the procedures that apply to that shipment rather than treating all hazardous materials alike.

Source: Commercial Driver’s License Manual – 2025 CDL Testing System — § 9.4, “Loading and Unloading”, 49 CFR § 177.834(c)–(f) — General Requirements

Question 2

Which group contains only steering-system components?

  1. A Tires, rims, and lug nuts
  2. B Leaf springs, U-bolts, and shock absorbers
  3. C Brake drums, linings, and slack adjusters
  4. D Steering column, steering gear box, and tie rods

Correct answer: D – Steering column, steering gear box, and tie rods

The steering column, steering gear box, and tie rods are steering-system components. During an inspection, look for bent, loose, broken, or missing steering parts and fasteners. If the vehicle has power steering, also inspect the hoses, pump, fluid level, and system for leaks.

Source: Commercial Driver’s License Manual – 2025 CDL Testing System — § 2.1.3, “What to Look For”

Question 3

Compared with a flat mirror, a convex mirror will:

  1. A Show a wider viewing area
  2. B Make objects appear closer than they are
  3. C Make objects appear larger than they are
  4. D Eliminate every blind spot around the vehicle

Correct answer: A – Show a wider viewing area

Convex mirrors show a wider area than flat mirrors and can help reduce blind areas. However, objects appear smaller and seem farther away than they actually are. Drivers must account for this distortion when judging the position and distance of nearby traffic.

Source: Commercial Driver’s License Manual – 2025 CDL Testing System — § 2.4.2, “Seeing to the Sides and Rear”

Question 4

For a typical dual-air system at operating rpm, which pressure increase should occur within 45 seconds?

  1. A From 85 to 100 psi
  2. B From 40 to 60 psi
  3. C From 60 to 80 psi
  4. D From 100 to 120 psi

Correct answer: A – From 85 to 100 psi

The South Carolina CDL manual states that a typical dual-air system should build from 85 to 100 psi within 45 seconds when the engine is at operating rpm. A vehicle with air tanks larger than the required minimum may take longer and still be safe. Always compare the result with the manufacturer’s specifications.

Source: Commercial Driver’s License Manual – 2025 CDL Testing System — § 5.3.3, “Step 7 Final Air Brake Check”

Question 5

Which braking systems are included in an air-brake-equipped commercial vehicle?

  1. A The service brake system
  2. B The parking brake system
  3. C The emergency brake system
  4. D All of these systems

Correct answer: D – All of these systems

Air brakes include service, parking, and emergency brake systems. The service system operates during normal braking, while the parking system applies and releases the parking brakes. The emergency system uses parts of the service and parking systems to stop the vehicle if a brake-system failure occurs.

Source: Commercial Driver’s License Manual – 2025 CDL Testing System — § 5, “Air Brakes”

Question 6

If an emergency requires you to drive onto the shoulder, which practice helps maintain control?

  1. A Move every wheel off the pavement immediately
  2. B Brake hard as soon as the first wheel leaves the road
  3. C Avoid braking, if possible, until slowing to about 20 mph
  4. D Assume the shoulder cannot support a commercial vehicle

Correct answer: C – Avoid braking, if possible, until slowing to about 20 mph

If possible, let the vehicle slow to about 20 mph before using the brakes. Then brake very gently to reduce the chance of skidding on the loose surface. Keep one set of wheels on the pavement when possible, and remain on a clear shoulder until the vehicle stops.

Source: Commercial Driver’s License Manual – 2025 CDL Testing System — § 2.17.1, “Leaving the Road”

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