South Dakota CDL Combination Practice Test (SD) 2

5 out of 5 (36 votes)
80% Passing score
20 Questions
4 Mistakes allowed
Preparing for your Commercial Driver's License (CDL) in South Dakota just got easier with our SD CDL combination practice test. Designed to help you ace the CDL combination test, this resource includes 20 multiple-choice questions covering crucial topics like inspection procedures, safe driving practices, air brake systems, and more. To pass, you'll need to answer at least 16 questions correctly. The varied questions will not only boost your confidence but also ensure you're thoroughly prepared for the permit test. One critical area you'll learn about is the risk of jackknifing, a dangerous situation where the trailer swings out of alignment with the tractor. Mastering smooth braking and careful handling techniques to avoid jackknifing is vital for safe driving. After completing the South Dakota drivers license practice, you can review your answers and go over any hints and explanations for the questions you missed. This feature is invaluable for reinforcing your knowledge and correcting any misunderstandings. Although the South Dakota CDL combination practice test does not replace a state-certified drivers ed or ELDT course, it complements your formal education by providing additional opportunities to understand and retain the material. You can take the DMV practice test as many times as needed until you feel comfortable with this set of questions. This flexibility allows you to build confidence and ensure you're ready for the next step in your CDL preparation. The SD DMV driving test practice is tailored to meet the specific needs of drivers in our state, taking into account unique driving conditions you might encounter across South Dakota. From the bustling roads of Sioux Falls to the more challenging terrains around the Black Hills and the open plains, this South Dakota practice permit test equips you with the skills and knowledge necessary for safe and efficient driving in various local environments. Whether you're navigating the icy roads in winter or dealing with high winds across the plains, our combination CDL practice test is an essential tool in your preparation. It's designed to help you succeed, not just in passing the test, but in becoming a safe, confident, and knowledgeable commercial driver in SD.
FREE CDL Practice Test App
Pass your South Dakota CDL Combination Vehicles test with the NextDoorDriving app. Real questions and answers—100% free and ad-free.
Download on the App Store

Sample South Dakota Combination Test Questions

Question 1

What damage may occur if a semitrailer is too low when the tractor backs underneath it?

  1. A The kingpin will automatically unlock
  2. B The air lines will be pulled apart
  3. C The tractor may strike and damage the trailer nose
  4. D No damage can occur because the trailer will always rise

Correct answer: C – The tractor may strike and damage the trailer nose

Set the trailer height so the fifth wheel lifts the trailer slightly as the tractor backs underneath. When the trailer is too low, part of the tractor may strike and damage its nose. Raise the trailer as needed and check that the kingpin and fifth wheel are properly aligned before backing under it.

Source: South Dakota Commercial Driver License Manual — § 6.4.1, “Coupling Tractor-Semitrailers”

Question 2

During a sudden steering movement while pulling doubles, which unit faces the greatest rollover risk?

  1. A The rear trailer, which may be about twice as likely to roll as the tractor
  2. B Both trailers face exactly the same risk
  3. C The front trailer, which is twice as likely to roll as the tractor
  4. D The tractor and both trailers face identical risks

Correct answer: A – The rear trailer, which may be about twice as likely to roll as the tractor

Rearward amplification produces the combination vehicle’s crack-the-whip effect. A quick steering movement becomes more pronounced toward the rear, making the last trailer especially vulnerable to rollover. Steer gently and smoothly, look far ahead, and slow before turns to avoid sudden steering corrections.

Source: South Dakota Commercial Driver License Manual — § 6.1.2, “Steer Gently”

Question 3

What is the main safety benefit of using a helper while backing a combination vehicle?

  1. A The helper can watch blind areas and signal before the vehicle hits an obstacle
  2. B The helper can make the vehicle back faster
  3. C The helper can operate the vehicle’s brakes
  4. D The helper can adjust the mirrors while the vehicle moves

Correct answer: A – The helper can watch blind areas and signal before the vehicle hits an obstacle

The South Dakota manual recommends using a helper whenever possible because every commercial vehicle has blind areas. Position the helper near the rear where the driver can see them. Before backing, agree on clear hand signals, including a stop signal, and stop immediately if the helper disappears from view.

Source: South Dakota Commercial Driver License Manual — § 2.2.4, “Backing Safely”

Question 4

What does the red, eight-sided trailer air-supply control do?

  1. A It applies the tractor parking brakes only
  2. B It mechanically holds the trailer to the tractor
  3. C It adjusts the tractor’s air-compressor pressure
  4. D It supplies air to the trailer or shuts off the air and applies the trailer emergency brakes

Correct answer: D – It supplies air to the trailer or shuts off the air and applies the trailer emergency brakes

Pushing in the trailer air-supply control opens the tractor protection valve and supplies air to the trailer. Pulling the control out shuts off that air and applies the trailer emergency brakes. On newer vehicles, this control is normally a red, eight-sided knob.

Source: South Dakota Commercial Driver License Manual — § 6.2.3, “Trailer Air Supply Control”

Question 5

What adjustment should you make when a semitrailer is too high for proper fifth-wheel coupling?

  1. A Raise the trailer farther
  2. B Back under it at a higher speed
  3. C Approach it at an angle
  4. D Lower the trailer

Correct answer: D – Lower the trailer

Lower the trailer until it is positioned so the tractor will raise it slightly while backing underneath. This allows the trailer apron to contact the fifth wheel correctly and helps the kingpin enter the locking jaws. Recheck alignment before continuing the coupling procedure.

Source: South Dakota Commercial Driver License Manual — § 6.4.1, “Coupling Tractor-Semitrailers”

Question 6

After coupling a tractor and semitrailer, how much space is acceptable between the trailer apron and the fifth-wheel plate?

  1. A One to two inches
  2. B Two to five inches
  3. C At least five inches
  4. D No space

Correct answer: D – No space

The trailer must lie flat on the fifth-wheel plate with no space between the upper and lower fifth-wheel surfaces. A gap can indicate an improper coupling, such as the kingpin sitting above the closed jaws. Inspect the jaws around the kingpin shank, the locking lever, and the safety latch before driving.

Source: South Dakota Commercial Driver License Manual — § 6.4.1, “Coupling Tractor-Semitrailers”

More South Dakota CDL Practice Tests
Other CDL Endorsements