How many questions are on the Illinois CDL knowledge test?

The Illinois CDL general knowledge test has 30 multiple-choice questions, and you need 80% (24 correct) to pass. The General Knowledge test is shorter. Most states do not publish its question count, but the 80% pass mark is federal under 49 CFR 383.135 and applies to every CDL knowledge test.

What's the minimum age for a CDL in Illinois?

In Illinois, the minimum age for a CDL is 18 (intrastate); 21 (interstate). Federal law requires drivers to be 21+ to drive a CMV across state lines or to transport hazardous materials, regardless of state minimum age.

Do I have to pass General Knowledge before any endorsement test?

For a first CDL, yes: General Knowledge is the foundation every applicant sits and the endorsement tests build on it. A driver who already holds a CDL and is adding an endorsement does not retake it. Texas is the one exception to the ordering, since its Special Requirements exam comes before General Knowledge.

Do I have to pass the General Knowledge test before any other CDL test?

Yes. The General Knowledge test is the gateway test for the CDL. You must pass it before you can take any endorsement tests (HazMat, Tanker, Passenger, School Bus, Doubles/Triples) or class-specific tests (Combination Vehicles for Class A). Once you pass General Knowledge, you receive a CDL learner's permit and can begin behind-the-wheel practice and additional knowledge tests.

How many questions are on the CDL General Knowledge test?

Most states use 50 multiple-choice questions for the General Knowledge test, but a handful of states use slightly different counts. You need 80% to pass in every state. Check your state's CDL manual or our state-specific page for the exact number of questions in your state.

Can I take the General Knowledge test online?

A few states allow CDL knowledge tests online, but most still require in-person testing at a DMV testing center to verify identity and prevent cheating. Check with your state DMV before assuming an online option is available.

How is the CDL General Knowledge test different from the regular driver's license test?

The CDL General Knowledge test focuses on heavy commercial vehicles, their longer braking distances, blind spots, hours-of-service rules, cargo securement, and the federal regulations that apply to interstate commerce. The regular driver's license test covers passenger cars and basic road rules. Even experienced drivers find the CDL General Knowledge content significantly different and broader than the standard driver test.

Do I need to retake the General Knowledge test if my CDL expires?

Each state sets its own rules. If your CDL has been expired for a short period (typically under a year), most states allow a straightforward renewal without re-testing. If your CDL has been expired for several years, your state may require you to retake the General Knowledge test and possibly the skills test. Always check with your state DMV for current rules.

Illinois CDL general knowledge practice test

Updated for 2026 · 112 general knowledge questions of 480 across the full IL CDL path · Aligned to the commercial driver manual · Part of the IL CDL path

The foundation every CDL applicant sits, whatever class you are after. Covers vehicle control, safe driving, cargo basics and the federal rules behind them.

Choose a practice test

4 tests, each drawing from a different question pool. Take all 4 to cover the full 112 questions.

Quick test

25 random questions from the general knowledge pool. Try it free.

25 questions80% to pass

Start Practicing

Practice test 2

PRO

25 fresh questions, sample 2 of the general knowledge pool. No overlap with the Quick Test or other Practice Tests.

25 questions80% to pass

Unlock

Practice test 3

PRO

25 fresh questions, sample 3 of the general knowledge pool. No overlap with the Quick Test or other Practice Tests.

25 questions80% to pass

Unlock

Full coverage

PRO

50 questions covering the full general knowledge bank. Take when you're ready for everything.

50 questions80% to pass

Unlock

Drill 50 General Knowledge Questions

PRO

Drill every question in this section with full explanations.

Unlock

Your IL CDL study path

Core

1
General Knowledge
Not started

Vehicle tests

Endorsements

Know exactly when you're ready

The IQ Readiness Score measures six dimensions of CDL test readiness: memory stability, test performance, content coverage, recent accuracy, difficulty mastery, and reaction speed.

See Plans & PricingStarting at $12.99 · 48-hour money-back guarantee

7,500+ questions51 official handbooksVerified August 2026

Included with Pro

6-dimension CDL analysisTracks your readiness across General Knowledge, Air Brakes, HazMat, and every CDL endorsement you're studying for.

Personalized CDL study pathAutomatically prioritizes your weakest CDL topics and endorsement areas so you study what matters most.

CDL pass probabilityReal-time estimate of your likelihood of passing based on your practice performance across all CDL sections.

Weak topic recoveryIdentifies and re-drills the specific CDL topics dragging your score down until they become strengths.

About the Illinois General Knowledge test

The General Knowledge test has 50 multiple-choice questions in most states (some states use a slightly different question count). You need an 80% score to pass. Topics include safe driving practices, transporting cargo safely, vehicle inspection procedures, communication with other drivers, speed and space management, hazard awareness, distracted-driving rules, fatigue and hours of service basics, accident procedures, and the consequences of alcohol and controlled substance use. The test draws from the General Knowledge section of your state's CDL manual. This is a separate knowledge test from General Knowledge, required in every state under 49 CFR 383.71, and the Secretary of State publishes the Illinois Commercial Driver's License Study Guide as the study source for it.