Alabama CDL Combination Practice Test (AL) 2

5 out of 5 (32 votes)
80% Passing score
20 Questions
4 Mistakes allowed
Get ready to ace your Alabama CDL combination test with this comprehensive and balanced CDL combination practice test. Designed to prepare you thoroughly, this Alabama DMV practice test includes 20 multiple-choice questions that cover crucial topics such as inspection procedures, safe driving practices, and air brake systems. To pass, you must answer at least 16 questions correctly. The varied questions in this Alabama CDL combination test will help build your confidence, ensuring you're well-prepared for the official test. Unique driving conditions across Alabama, from the bustling city streets of Birmingham to the winding rural roads of the Appalachian foothills, demand a well-rounded understanding of safe driving techniques. One of the critical areas this practice permit test covers is the risk of jackknifing, a dangerous situation where the trailer swings out of alignment with the tractor. Learning to avoid this through smooth braking and careful handling is essential for safe driving, especially on Alabama's diverse roadways. Unlike timed exams, this combination CDL test allows you to spend as much time as you need on each question, enabling you to thoroughly understand and absorb the material. This feature is particularly beneficial for those who prefer to learn at their own pace. Additionally, supplementing your study with the Alabama driver's handbook, a state-certified driver's ed course, flashcards, and road sign charts can enhance your preparation, targeting all areas of the DMV permit test. Visual aids are integrated into many of the sample permit test questions on this Alabama permit practice test. These aids include images that help you better understand the questions, which is particularly helpful for visual learners. Whether you are navigating the sandy soils of southern Alabama or the hilly terrains up north, this Alabama combination CDL practice test provides the robust preparation you need to confidently tackle the real test.
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Sample Alabama Combination Test Questions

Question 1

Which procedure correctly tests a trailer’s emergency brakes?

  1. A Open both shut-off valves at the rear of the last trailer
  2. B Charge the trailer system, pull out the trailer air-supply control, and gently pull against the trailer
  3. C Turn off the engine and repeatedly press the brake pedal until the warning activates
  4. D Release every parking brake and move forward at normal speed

Correct answer: B – Charge the trailer system, pull out the trailer air-supply control, and gently pull against the trailer

First charge the trailer air system and verify that the trailer can roll freely. Stop, pull out the trailer air-supply control or place it in the emergency position, and then gently pull against the trailer. The Alabama manual uses this procedure to confirm that the trailer emergency brakes have applied and are holding.

Source: Alabama Commercial Driver License Manual — § 6.5.2, “Combination Vehicle Brake Check”

Question 2

What is the function of the trailer air-supply control?

  1. A It applies only the tractor’s front brakes
  2. B It mechanically holds the trailer to the fifth wheel
  3. C It measures air pressure in the trailer tanks
  4. D It supplies air to the trailer, shuts that air off, and applies the trailer emergency brakes

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

Pushing in the trailer air-supply control sends air to the trailer and opens the tractor protection valve. Pulling it out shuts off the air supply and applies the trailer emergency brakes. On older vehicles, the same control may be a lever with “normal” and “emergency” positions instead of a red knob.

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

Question 3

Which action can damage a semitrailer’s landing gear while uncoupling?

  1. A Keeping the tractor directly aligned with the trailer
  2. B Lowering the landing gear onto a firm supporting surface
  3. C Pulling the tractor out at an angle
  4. D Relieving pressure on the fifth-wheel locking jaws

Correct answer: C – Pulling the tractor out at an angle

The tractor and trailer should be aligned before uncoupling. Pulling out at an angle can place sideways force on the landing gear and damage it. After the landing gear is properly lowered and the coupling is released, pull the tractor straight forward until it is clear of the trailer.

Source: Alabama Commercial Driver License Manual — § 6.4.2, “Uncoupling Tractor-Semitrailers”

Question 4

Which statement is correct about air-braked trailers manufactured before January 1, 1975?

  1. A They may not be equipped with spring brakes
  2. B They are required to have an antilock braking system
  3. C They must use a special glad-hand adapter
  4. D They cannot use emergency brakes powered by stored air

Correct answer: A – They may not be equipped with spring brakes

Federal equipment requirements do not make spring brakes mandatory for every air-braked trailer manufactured before January 1, 1975. An older trailer without spring brakes uses air stored in its tank to operate the emergency brakes. Those brakes hold only while air pressure remains, making wheel chocks important when such a trailer is parked.

Source: Alabama Commercial Driver License Manual — § 6.2.8, “Trailer Service, Parking and Emergency Brakes”, 49 CFR § 393.41(b) – Parking brake system

Question 5

Why should the trailer hand valve not be used for routine braking while driving?

  1. A It cannot apply any trailer brakes
  2. B It automatically releases the tractor parking brakes
  3. C It prevents the brake lights from operating
  4. D Applying only the trailer brakes can cause the trailer to skid

Correct answer: D – Applying only the trailer brakes can cause the trailer to skid

Using the hand valve during normal driving can lock the trailer wheels and cause a skid or jackknife. The Alabama manual limits its use to testing the trailer brakes. The foot brake applies the brakes throughout the combination, creating less danger of a trailer skid than braking only the trailer.

Source: Alabama Commercial Driver License Manual — § 6.2.1, “Trailer Hand Valve”

Question 6

Why is rearward amplification dangerous in a combination vehicle?

  1. A It delays air-compressor operation
  2. B It increases the rear trailer’s rollover risk during sudden steering movements
  3. C It increases fuel use during straight-line travel
  4. D It prevents the trailer wheels from off-tracking

Correct answer: B – It increases the rear trailer’s rollover risk during sudden steering movements

Rearward amplification causes the crack-the-whip effect, making a quick steering movement more severe at the rear of the combination. The last trailer can respond strongly enough to overturn even when the tractor remains upright. Smooth steering, gradual lane changes, and reducing speed before turns help limit this danger.

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

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