CDL Permit Practice Test: What's on the CLP Knowledge Exam

What the CDL permit (CLP) test covers

The CDL permit test is the written knowledge exam you pass to earn your Commercial Learner's Permit. It is written and administered by your state DMV from that state's CDL manual — there is no single national CDL permit test, which is why question counts and passing scores differ from state to state.

For a Class A permit you will normally sit three sections. **General Knowledge** (~50 questions) covers rules of the road, road signs, vehicle inspection, safe driving procedures, cargo handling, and the effects of alcohol and fatigue. **Air Brakes** (~25 questions) covers system components, the low-air-pressure warning, spring brakes, and correct parking-brake use — skip it and you get an air-brake restriction on your licence. **Combination Vehicles** (~25 questions) covers coupling and uncoupling, trailer handling, and rollover prevention.

Adding an endorsement means an extra section: Hazmat (H), Passenger (P), School Bus (S), Tanker (N), or Doubles/Triples (T) each have their own knowledge test. If you are deciding which to take, our Which CDL Endorsement Should I Get? guide breaks down which ones require ELDT and which are knowledge-test only.

How many questions, and what score do you need?

Most states use roughly 50 General Knowledge questions with a passing score around 80% — meaning about 40 correct. Air Brakes and Combination Vehicles are usually ~25 questions each at the same threshold. Because each state sets its own numbers, treat your state DMV's CDL manual as authoritative rather than any figure you read online, including this one.

Nearly every state lets you retake a failed section, though most impose a waiting period (commonly 1–7 days) and many charge a retest fee. Sections you have already passed generally carry over, so a failed Air Brakes section does not usually mean re-sitting General Knowledge.

The permit test is not ELDT — first-time applicants need both

This is the single most common point of confusion, and it costs people time and money. The **CDL permit test** is a state DMV knowledge exam that earns you a CLP. **ELDT** is a separate federal requirement: FMCSA-approved entry-level driver training that must be completed by an approved provider and reported to the federal Training Provider Registry before you may take the CDL *skills* test.

Practice-test products — including DLA Academy's — are study aids. They are **not** FMCSA-approved and do **not** satisfy the ELDT mandate. Anyone selling you a "CDL permit test" as ELDT is misleading you. If you are a first-time Class A applicant you will need the permit test to get your CLP, then FMCSA-approved CDL-A Theory ELDT at $20 to qualify for the skills test, then behind-the-wheel training at a local FMCSA-registered provider. See ELDT vs CDL School for how the pieces fit together.

How to study and what to bring

Start with your state DMV's CDL manual — it is free, and the test questions are drawn directly from it. Read the General Knowledge, Air Brakes, and Combination Vehicles chapters, then test yourself rather than re-reading; recall practice is what moves the score. Plenty of free question banks exist online, and they are worth using.

If you want a structured bank that mirrors the DMV interface, DLA Academy's CDL Permit Prep is $15 for 119 questions — roughly 50 General Knowledge, 25 Air Brakes, 25 Combination Vehicles, plus sample Hazmat questions — with unlimited retakes and review of missed items. Most drivers run the full bank twice before testing.

On test day bring proof of identity, proof of state residency, your Social Security number, and your DOT medical card if your state requires it at the permit stage. Once you pass, you must hold the CLP for **at least 14 days** before taking the CDL skills test — that federal minimum applies in every state, so factor it into your timeline.

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