CDL Quest

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7-Minute CDL Study Focus Check

Answer nine questions without looking at the key. Mark one point for each correct answer, then use the topic totals to choose what to study first.

Print the two-page PDF Not a pass prediction or an official exam.
General KnowledgeQuestions 1-3

1. When another driver is tailgating your commercial vehicle, what is the safest response?

2. If your vehicle begins to hydroplane, what should you do first?

3. After an emergency stop on the road or shoulder, warning devices must be placed within:

Air BrakesQuestions 4-6

4. After fully charging the air system, how do you test the low-pressure warning?

5. As pressure continues to fall, spring brakes should pop on at about:

6. With S-cam brakes released, a push rod pulled by hand should move:

Combination VehiclesQuestions 7-9

7. When connecting glad hands, the trailer service line is usually marked:

8. What can happen if a trailer is too high when you back under it?

9. When you have a choice, the safest direction for backing a tractor-trailer is:

Check your work

Answer key and first study step

1. C

Open more space ahead so you can slow gradually and let the tailgater pass. Source cue: CDL Manual section 2.8.

2. A

Ease off the accelerator, use the clutch if equipped, and avoid braking until traction returns. Source cue: CDL Manual section 2.6.

3. D

Place warning devices within 10 minutes of the emergency stop. Source cue: 49 CFR 392.22.

4. B

With the engine off and electrical power on, fan the brakes and note when the warning activates. Source cue: CDL Manual section 5.3.

5. C

Spring brakes should activate in the 20-45 PSI range. Source cue: CDL Manual section 5.3.

6. A

More than about one inch of movement can indicate a brake-adjustment problem. Source cue: CDL Manual section 5.2.

7. D

The service/control line is blue; the emergency/supply line is red. Source cue: CDL Manual section 6.3.

8. B

A high trailer may let the tractor slide under without the jaws locking around the kingpin. Source cue: CDL Manual section 6.2.

9. C

Back toward the driver's side when possible so the trailer path is easier to see. Source cue: CDL Manual section 6.1.

Choose what to study first

Add each topic separately: General Knowledge (1-3), Air Brakes (4-6), and Combination Vehicles (7-9).

  • 0-1 correct: begin with that bank and its current state-manual section.
  • 2 correct: review the missed concept, then take a focused quiz.
  • 3 correct: keep the topic in rotation; this tiny sample does not prove mastery.

Start with the lowest topic. If topics tie, start with the one required for your selected CDL route that feels least familiar.

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Practice the topic you found in CDL Quest.

Free Starter access includes all 158 General Knowledge questions.

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Questions are adapted from CDL Quest's source-cleared federal-core practice bank. This check is an independent study aid, not an official exam or pass prediction. Always use your state's current CDL manual and licensing agency requirements as the authority. FMCSA provides a state manual directory.