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CDL Class A Knowledge Tests Practice Test

298 practice questions across 3 topics, each with a written explanation of why the correct answer is correct. Start below — the first questions are free and no account is required.

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Topics on the CDL Class A Knowledge Tests exam

Sample CDL Class A Knowledge Tests questions

General Knowledge

How far ahead should you look while driving a commercial vehicle?

  1. A. 3–5 seconds
  2. B. 6–8 seconds
  3. C. 12–15 seconds
  4. D. 30 seconds

Answer: C. The CDL manual says to look 12 to 15 seconds ahead — about a quarter mile at highway speed — so you can spot hazards early.

Air Brakes

In a dual air brake system, pressure should build from 85 to 100 psi within about:

  1. A. 2 minutes
  2. B. 5 minutes
  3. C. 15 seconds
  4. D. 45 seconds

Answer: D. With the engine at operating rpm, pressure should rise from 85 to 100 psi within about 45 seconds in dual air systems.

Combination Vehicles

Which combination vehicle is most likely to turn over because of the 'crack-the-whip' effect?

  1. A. A bobtail tractor
  2. B. A tractor with one semitrailer
  3. C. A tractor pulling triple trailers, especially the last trailer
  4. D. A straight truck

Answer: C. Rearward amplification makes the last trailer swing most. Triples are the most likely to roll over, then doubles, then a tractor-semitrailer.

Work through every topic on the CDL Class A Knowledge Tests question directory, or start the timed practice test above.

CDL Class A Knowledge Tests exam — frequently asked questions

How many questions are on the CDL Class A Knowledge Tests exam?

The CDL Class A Knowledge Tests exam typically has Varies by state (General Knowledge ~50, Air Brakes ~25, Combination ~20). The exact count varies by state and exam version. VoltExam gives you 298 practice questions covering every topic tested.

What score do you need to pass the CDL Class A Knowledge Tests exam?

The passing score for the CDL Class A Knowledge Tests exam is typically 80% in most states. Scoring significantly above the minimum on practice tests before exam day is strongly recommended to account for real-exam pressure.

What is the pass rate for the CDL Class A Knowledge Tests exam?

The sponsor of the CDL Class A Knowledge Tests exam does not publish a pass rate, so VoltExam does not estimate one or claim that practice predicts the result.

How long should I study for the CDL Class A Knowledge Tests exam?

Most candidates study 2–4 weeks for the CDL Class A Knowledge Tests exam. Study time varies based on prior experience. Focusing on practice questions with explanations is the most time-efficient preparation method.

What topics are on the CDL Class A Knowledge Tests exam?

The CDL Class A Knowledge Tests exam covers topics including: General Knowledge, Air Brakes, Combination Vehicles. VoltExam's free study mode organizes 298 quick-study questions by concept so you can target weak areas efficiently.