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From Sections 1, 2, 3 and 15 of the Illinois Commercial Driver’s License Study Guide

Illinois CDL General Knowledge Practice Test

Who takes it: every CDL class (A, B and C).

Inspection, safe driving and cargo: every CDL applicant takes it. 30 questions, 24 right to pass (80%).

Study mode

Practice General Knowledge

  • 10questions a round
  • 11manual sections
Exam mode

Take the General Knowledge test

  • 30questions
  • 24correct to pass
  • –no test taken yet
Sections 1–15 · p. 2–172 of the Illinois Commercial Driver’s License Study Guide (July 2025 (DSD CDL 10.30)), opens in a new tab

A General Knowledge question to try

Your truck has air-over-hydraulic brakes. Do you need the Air Brakes test?

Tap an answer to see if you’re right, and the page

Where it is in the Illinois Commercial Driver’s License Study Guide

Your score on each part fills in as you study.

  • Manual section 1 · 3 topics
  • Illinois CDL classes, endorsements, requirements and testsNot practiced yetp. 2 to 8
  • Disqualifications and other CDL rulesNot practiced yetp. 10 to 12
  • Illinois safety tests, phones, size limits, lights and registrationNot practiced yetp. 13 to 18
  • Manual section 2 · 6 topics
  • Vehicle inspectionNot practiced yetp. 19 to 26
  • Vehicle control, shifting, seeing and communicatingNot practiced yetp. 27 to 32
  • Speed, space, hazards, distractions and road rageNot practiced yetp. 33 to 42
  • Night, fog, winter, heat, railroad crossings and mountainsNot practiced yetp. 43 to 50
  • Emergencies, ABS, skids, crashes and firesNot practiced yetp. 51 to 57
  • Alcohol, drugs, fatigue and hazmat basicsNot practiced yetp. 58 to 62
  • Manual section 3
  • Transporting cargo safelyNot practiced yetp. 63 to 65
  • Manual section 15
  • Military waiver and medical certificationNot practiced yetp. 166 to 172

Only in the Illinois manual

Rules for this test that the Illinois Commercial Driver’s License Study Guide prints and other states' manuals don't.

  • Illinois Fast Pass

    Illinois Fast Pass lets applicants schedule CDL exams online at any time; anyone who must cancel a CDL appointment is asked to give 24 hours' notice. p. 8

  • Serious Traffic Violations

    A conviction for any traffic-control violation (other than parking) connected with a fatal traffic accident brings an Illinois CDL disqualification of at least 12 months. p. 11

  • While You Are Driving

    A drowsy driver can fall asleep without knowing it and have micro sleeps, brief naps of about four or five seconds; at 55 mph that is more than 100 yards, plenty of time for a crash, and a sleep debt puts you at risk even if you don't feel drowsy. p. 60

  • Hazardous Materials Rules For All Commercial Drivers

    Illinois' manual: placards are signs on the outside of a vehicle that show the hazard class of the cargo; a placarded vehicle needs at least four identical placards (front, rear and both sides), readable from all four directions and at least 10 3/4 inches square, set on a point in a diamond shape. p. 61

Illinois answers about this test

CDL General Knowledge Test guide30 rules, with the pages in each state's manual

Practice material, not the official test: check every answer in your state's current handbook. Disclaimer · How the rounds work · SOS

All Illinois CDL tests