South Dakota CDL Practice Test: General Knowledge (SD) 6

5 out of 5 (33 votes)
80% Passing score
50 Questions
10 Mistakes allowed
Aspiring commercial driver, here's your essential tool for acing the South Dakota DMV's CDL General Knowledge test: our comprehensive online DMV practice test, tailored just for you. This sixth installment in our series is designed to thoroughly prepare you for what lies ahead in your CDL journey. Imagine sitting for the actual DMV test but in the comfort of your home or anywhere you prefer. That's what our SD CDL practice test offers. With a set of 50 carefully chosen permit test questions and answers, this test mirrors the real general knowledge test in both style and substance. You'll encounter DMV questions on a variety of crucial topics, from managing road emergencies to understanding the nuances of hazardous materials. Yes, even though HazMat endorsements aren't your current focus, a basic understanding is vital for every commercial driver. Our South Dakota DMV CDL practice test adopts the multiple-choice and true/false format, exactly like the actual CDL written test. This setup isn't just about answering a bunch of permit test questions; it's about sharpening your skills in identifying the correct answers, an invaluable technique for the real written permit test. There's no limit to how many times you can take this South Dakota DMV permit practice test. Repeated attempts are not just allowed but encouraged. Each attempt is an opportunity to solidify your knowledge and boost your confidence. You'll need to score at least 40 out of 50 to pass, but remember, mastering this CDL practice test is about more than just passing. It's about becoming a safer, more knowledgeable driver. Behind every question is a team of professional driving instructors with years of experience in guiding aspiring drivers. These experts have poured their knowledge into each sample DMV question, ensuring they are not only relevant but also up-to-date with the latest standards and regulations. So, go ahead, take the first step towards mastering the General Knowledge portion of your CDL written test. With this South Dakota CDL practice test, you're not just preparing for an exam; you're gearing up for a successful driving career that starts in 2026!
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Sample South Dakota CDL Test Questions - General Knowledge

Question 1

Which serious driving errors may result from alcohol impairment?

  1. A Longer reaction time when hazards appear
  2. B Improper speed or driving in the wrong lane
  3. C Striking a curb or weaving
  4. D All of these answers are correct

Correct answer: D – All of these answers are correct

Alcohol affects judgment, vision, coordination, and reaction time. Resulting errors may include delayed responses to hazards, driving too fast or too slowly, using the wrong lane, striking curbs, and weaving. Each listed behavior is associated with alcohol-impaired driving.

Source: South Dakota Commercial Driver License Manual — § 2.22.1, “Alcohol and Driving”.

Question 2

An individual cargo article is blocked against forward movement and is exactly 20 feet long. What minimum tie-down arrangement is required?

  1. A One tie-down for the entire article
  2. B Four tie-downs—two for each 10 feet
  3. C Four tie-downs—one for each 5 feet
  4. D Two tie-downs—one for each 10 feet

Correct answer: D – Two tie-downs—one for each 10 feet

Federal cargo-securement rules require at least one tie-down for every 10 feet of length, or fraction thereof, when an individual article is properly blocked, braced, or immobilized against forward movement. An article that is exactly 20 feet long therefore requires at least two tie-downs. Different minimums apply when the article is not blocked against forward movement.

Source: 49 CFR § 393.110(c) – Additional requirements for determining the minimum number of tiedowns.

Question 3

Underinflated tires are a possible cause of a commercial-vehicle fire.

  1. A TRUE
  2. B FALSE

Correct answer: A – TRUE

Underinflated tires are identified as a possible cause of vehicle fires. Dual tires that touch are another tire-related fire hazard. Drivers should inspect tire condition and inflation and monitor for signs of overheating or smoke while traveling.

Source: South Dakota Commercial Driver License Manual — § 2.21.1, “Causes of Fire”.

Question 4

What should be the principal method of controlling speed on a long or steep downgrade?

  1. A Apply the brakes whenever speed rises 5 mph above the safe speed
  2. B Use repeated stab braking throughout the grade
  3. C Use the braking effect of the engine
  4. D Apply only the trailer brakes

Correct answer: C – Use the braking effect of the engine

Engine braking should be the principal means of controlling speed on a downgrade. The transmission should be shifted into the proper low gear before starting down the grade. Service brakes supplement the engine's braking effect and must remain available when slowing or stopping is required by traffic or roadway conditions.

Source: South Dakota Commercial Driver License Manual — § 2.16.1, “Select a ‘Safe’ Speed”; § 2.16.4, “Proper Braking Technique”.

Question 5

Which statement correctly describes stab braking?

  1. A It should never be used under any circumstances
  2. B The brakes are fully applied, released when the wheels lock, and reapplied after the wheels roll
  3. C The driver maintains unchanging brake pressure without wheel lockup
  4. D The driver holds the wheels locked until the vehicle stops

Correct answer: B – The brakes are fully applied, released when the wheels lock, and reapplied after the wheels roll

With stab braking, the driver applies the brakes fully and releases them when the wheels lock. The brakes are applied fully again as soon as the wheels begin rolling. Reapplying them before the wheels roll can prevent the vehicle from straightening, while holding the wheels locked causes a skid and loss of control.

Source: South Dakota Commercial Driver License Manual — § 2.17.2, “How to Stop Quickly and Safely”.

Question 6

Which driver actions can cause a skid?

  1. A Oversteering
  2. B Overbraking
  3. C Driving too fast for conditions
  4. D All of the above

Correct answer: D – All of the above

A skid occurs when the tires lose their grip on the road. Overbraking can lock the wheels, while oversteering asks the vehicle to turn more sharply than available traction permits. Driving too fast for conditions is a major cause of serious skids and may also lead to excessive braking or steering.

Source: South Dakota Commercial Driver License Manual — § 2.19, “Skid Control and Recovery”.

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