Free Illinois CDL Practice Test
Illinois uses the national CDL manual and federal question pool. Practice every knowledge test here, then check Illinois’s own question counts, passing scores and fees below.
General Knowledge and every endorsement test at the length states use, three answer choices per question, scored at the real 80% pass mark with an explanation from the CDL manual for every answer.
Or start with a free 10-question drillYou are driving a 50-foot vehicle at 35 mph. How many seconds of following distance should you keep?
Illinois CDL knowledge tests
| Test | Questions | Correct to pass | Practice |
|---|---|---|---|
| General Knowledge | 30 | 24 | General Knowledge practice |
| Air Brakes | 25 | 20 | Air Brakes practice |
| Combination Vehicles | 20 | 16 | Combination Vehicles practice |
| Hazardous Materials | 30 | 24 | Hazardous Materials practice |
| Tank Vehicles | 20 | 16 | Tank Vehicles practice |
| Doubles and Triples | 20 | 16 | Doubles and Triples practice |
| Passenger Transport | 20 | 16 | Passenger Transport practice |
| School Bus | 20 | 18 | School Bus practice |
Practice before your IL knowledge tests
General Knowledge and every endorsement test at the length states use, three answer choices per question, scored at the real 80% pass mark with an explanation from the CDL manual for every answer.
Or start with a free 10-question drillTaking the tests in Illinois
- Where
- At Secretary of State CDL facilities, on a computer that draws random questions. Tests are in English; an audio version is available on request.
- Commercial learner’s permit
- Valid for one year. Hold it at least 14 days before the skills test; knowledge test results are valid for up to one year.
- If you fail
- You get three attempts at each test per fee paid. After three failures of the same test you wait 30 days, after six 90 days, and after nine one year.
- Good to know
- Illinois’s General Knowledge test has 30 questions, not the 50 most states use, and the School Bus test needs 90% (18 of 20). Illinois also has its own 20-question Charter Bus endorsement test.
Illinois CDL fees
- Commercial learner’s permit: $50
- Upgrade a class or add or remove an endorsement or restriction: $5
- CDL renewal or out-of-state transfer (ages 18 to 69): $60
Illinois CDL test questions
How many questions are on the Illinois CDL permit test?
The Illinois General Knowledge test has 30 questions and you need 24 correct. Air Brakes: 25 questions, 20 to pass; Combination Vehicles: 20 questions, 16 to pass; Hazardous Materials: 30 questions, 24 to pass; Tank Vehicles: 20 questions, 16 to pass; Doubles and Triples: 20 questions, 16 to pass; Passenger Transport: 20 questions, 16 to pass; School Bus: 20 questions, 18 to pass.
Where do I take the CDL knowledge tests in Illinois?
At Secretary of State CDL facilities, on a computer that draws random questions. Tests are in English; an audio version is available on request.
How much does a Illinois CDL permit cost?
the Illinois Secretary of State lists: Commercial learner’s permit $50; Upgrade a class or add or remove an endorsement or restriction $5; CDL renewal or out-of-state transfer (ages 18 to 69) $60.
What if I fail a CDL knowledge test in Illinois?
You get three attempts at each test per fee paid. After three failures of the same test you wait 30 days, after six 90 days, and after nine one year.
Ready for the knowledge tests?
General Knowledge and every endorsement test at the length states use, three answer choices per question, scored at the real 80% pass mark with an explanation from the CDL manual for every answer.
Or start with a free 10-question drillMore CDL practice
- CDL General Knowledge practice test
- CDL Air Brakes practice test
- CDL Combination Vehicles practice test
- CDL Hazardous Materials practice test
- CDL Tank Vehicles practice test
- CDL Doubles and Triples practice test
- CDL Passenger Transport practice test
- CDL School Bus practice test
- Pennsylvania CDL practice test
- Michigan CDL practice test
- Washington CDL practice test
- Missouri CDL practice test
Illinois facts are from the Illinois Secretary of State, checked October 2026: Illinois CDL Study Guide (July 2025) · Illinois Secretary of State: CDL and CLP.
Original independent practice. Not affiliated with or endorsed by the Illinois Secretary of State, FMCSA or AAMVA.