Illinois CDL Practice Test

Everyone takes General Knowledge. Add Combination for Class A, Air Brakes for full or partial air brakes, and a test for each endorsement you want: Passenger, School Bus, Tank Vehicle, Hazardous Materials, Doubles/Triples or the Illinois-only Charter Bus. Illinois Commercial Driver’s License Study Guide p. 7

At least 80 percent on each test, except the School Bus test, which needs 90 percent. Why 80% in every state →

General Knowledge 30, Air Brakes 25, Hazardous Materials 30, and 20 each for Combination, Passenger, Tank Vehicle, School Bus, Doubles/Triples and Charter Bus. Illinois Commercial Driver’s License Study Guide p. 7

You wait 30 days from the third failure of that test; six failures mean 90 days and nine mean a year. The wait applies only to the test you failed, and the fee is paid again to keep testing. Illinois Commercial Driver’s License Study Guide p. 8

English only, on a computer. You can ask for the audio format, and after trying it you can apply for an oral test read by Secretary of State staff.

The Illinois Commercial Driver’s License Study Guide: Illinois CDL rules and vehicle laws, inspection, safe driving, cargo, passengers, air brakes, combination vehicles, doubles and triples, tank vehicles, hazardous materials, school bus and charter bus, and the military waiver and medical certification programs. Illinois Commercial Driver’s License Study Guide p. 2

18 for a CLP or CDL and to haul hazardous materials within Illinois; 21 to drive across state lines or to carry passengers. Illinois Commercial Driver’s License Study Guide p. 5

A valid Illinois driver’s license with more than a year before it expires, documents proving your identity, birth date, residency, signature and Social Security number, proof of citizenship or lawful presence, and your medical self-certification. Illinois Commercial Driver’s License Study Guide p. 4

A CLP is valid for one year. You must hold it at least 14 days before the skills and drive tests, which you can schedule ahead for a date after the wait.

Yes for a first Class A or B CDL, an upgrade from B to A, and the P, S or H endorsements. The training provider must report it electronically before you can schedule skills tests, or before the hazmat test.

A pre-trip vehicle inspection, a basic control test (moving forward, parallel parking and backing into an offset lane) and an on-road driving test, all in a vehicle like the one you will drive. A part you pass doesn’t need retaking if you fail a later one. Illinois Commercial Driver’s License Study Guide p. 7

With a valid CDL (or one expired less than a year) of the same class and endorsements, you skip the written tests except hazmat, and you skip the skills tests unless you are 75 or older. Illinois Commercial Driver’s License Study Guide p. 6

Yes, for a first CDL, if you are active duty or discharged within 12 months. Even Exchange waives the knowledge and skills tests for certain military jobs; the Skills Waiver waives the skills tests only. Illinois Commercial Driver’s License Study Guide p. 166

Illinois Secretary of State, Driver Services lists the current fees for the commercial learner permit, the CDL tests and the license on its official fee page.

An endorsement only Illinois issues. You need it to drive a charter-type bus (not a school bus) that a school has hired to take students in grade 12 and under to school activities, unless you already hold P, S and a School Bus Permit for the same class. Illinois Commercial Driver’s License Study Guide p. 138

The S endorsement and an Illinois School Bus Permit. Permit applicants must be 21 or older, pass the school bus written and skills tests, a physical and a background check, and complete the State Board of Education training course, with yearly renewal requirements. Illinois Commercial Driver’s License Study Guide p. 135

Complete entry-level training, pass a TSA background check and get the approval letter, then pass the 30-question hazmat test. The TSA check is repeated at every CDL renewal. Illinois Commercial Driver’s License Study Guide p. 7

Every CDL holder and CLP applicant self-certifies in one of four categories at each CDL facility visit. Non-excepted interstate drivers need a DOT medical certificate, which since June 30, 2025 the medical examiner submits through the National Registry. Illinois Commercial Driver’s License Study Guide p. 171

Every four years, before it expires. Drivers who will be 75 or older at expiration retake the skills and drive tests to renew.

Among others: B corrective lenses, E automatic transmission only, K intrastate only, L no air brakes, Z no full air brakes, M and N passenger vehicle class limits, O no tractor-trailer, P no passengers and X no cargo in a tank (CLP only), V medical variance and J48 school bus only. Illinois Commercial Driver’s License Study Guide p. 4

Yes, a few federal rules. A first violation of an out-of-service order now costs your CDL for at least 180 days (the manual still says 90). If your license is suspended, revoked or canceled, or you are disqualified, tell your employer by the end of the next business day (the manual says within two business days).