Free practice + study guide

CDL General Knowledge

Commercial Driver's License (CDL) General Knowledge Test — Questions: Set by each state. The federal rule says each test must contain a set number of questions with a prescribed number from each knowledge area, but it fixes no number itself; check your state's CDL manual. · Time limit: The federal rules set no time limit for the knowledge test; any limit is set by the state. · Passing score: 80%. PrepPass also publishes a complete study guide for this exam as a downloadable book (72 pages, 55 practice questions inside, $9.99).

Exam inside two weeks?

A printable colour cheat sheet for the exam: the format, the content areas and the figures it turns on, each checked against a named source and dated.

CDL General Knowledge cheat sheet PDF — $9.99 →

6 pages · US Letter · printable PDF · yours to keep

01

Test what you know · free, all of it

Five ways to practise.

The same 120 questions, dealt five ways. Pick the one that fits the time you have.

02

Learn what the questions test

Practice finds the gaps. Reading closes them. The five chapters below are free to read online. The study guide book is a separate download, sold on its own page.

Practice · free
120
questions, each explained — finds what you don't know yet
Learn · the guide
72
pages in the study guide book, section by section

The five sections, as chapters

free to read online
  1. 1Safe Driving: Speed, Space, and Seeing HazardsSafe Driving · 27% of the exam — the largest sectionRead free →
  2. 2Vehicle Inspection: Pre-Trip, En-Route, and Post-TripVehicle Inspection · 23%Read free →
  3. 3Basic Control: Shifting, Backing, Turning, and CouplingControl & Operation · 18%Read free →
  4. 4Emergencies, Fires, Cargo, and Hazardous MaterialsEmergencies & Hazards · 17%Read free →
  5. 5Hours of Service, Licensing, and Driver FitnessRegulations & Health · 15%Read free →
Cover: CDL General Knowledge — Complete Study Guide (2026)
Study guide · PDF + EPUB
CDL General Knowledge — Complete Study Guide (2026)
72 pages · 55 practice questions inside · updated 2026-10-23
$9.99 one-time · yours to keep
03

Before you sit

Know the exam you're walking into.

04

See the questions first

Two from the bank, answered.

Real items, with the answer marked and the reason written out — the same format as all 120.

Safe Driving

You are driving a placarded hazardous materials load and approach an unguarded railroad crossing. What must you do?

  1. ASound the horn and cross at normal speed
  2. BStop directly on the first rail to get the best view
  3. CProceed without stopping if no train is visible
  4. DStop no closer than 15 feet and no farther than 50 feet from the nearest rail, look and listen, then cross without shifting gearsCorrect

Why: Placarded hazmat vehicles, most buses, and cargo tanks must stop between 15 and 50 feet from the nearest rail, check both directions, and cross in a gear that will not require shifting. Rolling through, relying on the horn, or stopping on the tracks all defeat the purpose of the required stop.49 CFR §392.10

Vehicle Inspection

You arrive for your shift and the tractor was driven by another driver yesterday. Before you move the vehicle, what does the federal rule require you to do first?

  1. ARoad test the vehicle for at least two miles before loading
  2. BReview the last driver vehicle inspection report and be satisfied the vehicle is in safe operating conditionCorrect
  3. CWeigh the loaded vehicle at the nearest certified scale
  4. DDrain the air tanks and rebuild pressure from zero

Why: A driver must review the previous driver's inspection report and sign it if defects were noted and certified as repaired, then be satisfied the vehicle is safe to operate. Draining tanks completely and rebuilding pressure is not a required daily step, weighing is a cargo issue rather than a pre-trip requirement, and no minimum road-test distance is required before loading.49 CFR §396.13

Read all 120 questions with answers →

06

The exam itself

CDL General Knowledge, by the numbers.

QuestionsSet by each state. The federal rule says each test must contain a set number of questions with a prescribed number from each knowledge area, but it fixes no number itself; check your state's CDL manual.
TimeThe federal rules set no time limit for the knowledge test; any limit is set by the state.
SectionsSafe Driving · Vehicle Inspection · Control & Operation · Emergencies & Hazards · Regulations & Health
Passing score80%49 CFR 383.135(a)(1): an applicant must correctly answer at least 80 percent of the questions on each knowledge test.
Our bank120 questions · updated September 2026Written from state Department of Motor Vehicles (under FMCSA standards)
LanguagesEnglish
Sourcestate Department of Motor Vehicles (under FMCSA standards)Verified 2026-09-24

Full facts and sources →

07

Helpful resources

The board's own page, and what else helps.

Find your state's DMV CDL page →

Recommended prep — books & tools

  • Barron's CDL: Commercial Driver's License Test

    Trusted prep brand covering the CDL general-knowledge test.

    See it on Amazon →

This section contains affiliate links. As an Amazon Associate, PrepPass earns from qualifying purchases. We may earn a commission if you buy through these links, at no extra cost to you.

08

CDL Exams & Endorsements

On the same path.

09

Questions

Asked before starting.

Is the practice really free, or does it stop after a few questions?

All 120 questions, the timed mock and the report are free with no sign-up. A free account only adds saving your progress. The study guide book is sold separately, $9.99 one-time; nothing in the practice requires it.

What score do I need?

80% — as published by state Department of Motor Vehicles (under FMCSA standards). Confirm the current rule with them before your exam date.

Is there a study guide for the CDL General Knowledge?

Yes. PrepPass sells CDL General Knowledge — Complete Study Guide (2026), a PDF + EPUB download, $9.99 one-time; the practice on this page stays free without it. See the study guide →

Practice questions are AI-assisted study material written from state Department of Motor Vehicles (under FMCSA standards) and reviewed by PrepPass — for practice only, not official exam questions. Bank updated September 2026. PrepPass is an independent study resource and is not affiliated with, endorsed by, or approved by state Department of Motor Vehicles (under FMCSA standards). Always confirm current exam details with state Department of Motor Vehicles (under FMCSA standards).
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