Free Illinois CDL Practice Test — Updated for 2025

Getting your Commercial Driver’s License in Illinois starts with the written knowledge tests. This page gives you free, simple Illinois CDL practice tests for every major section: General Knowledge, Air Brakes, Combination Vehicles, Hazmat, Passenger, School Bus, Tankers, and Doubles/Triples. Study one question at a time, see instant feedback, and read brief explanations after each answer.

Illinois CDL at a Glance (Plain-English Summary)

  • Age & eligibility:
    18+ for intrastate (within Illinois), 21 to drive interstate, carry hazmat or transport passengers.
  • Valid license & record:
    Must hold a valid Illinois driver’s license and have a clean record.
  • Medical card:
    CDL drivers must maintain a current DOT Medical Examiner’s Certificate and self-certify their driving category.
  • CLP:
    Pass the required written exams for your vehicle class (A/B/C) and any endorsements to earn your Commercial Learner’s Permit (CLP).
  • Skills test:
    Hold your CLP at least 14 days before taking the pre-trip, basic control, and on-road tests.
  • ELDT:
    Entry‑Level Driver Training applies (federal rule) for Class A/B and H/P/S endorsements before taking the skills test.
  • Hazmat:
    TSA background check required for Hazmat endorsement.
  • Where to test:
    Illinois Secretary of State (ILSOS) handles knowledge and skills tests through local Driver Services facilities and authorized third-party testers. Always verify current procedures and fees with ILSOS.
  • Tip:
    Rules, forms, and test fees can change. Confirm the latest information before scheduling.

What’s on the Idaho CDL Knowledge Tests

General Knowledge

— inspections, safe driving habits, space & speed management, night/weather driving, distractions/fatigue, emergencies, railroad crossings, and sharing the road.

Air Brakes

— parts and functions, dual-air systems, warning devices, spring brakes, and proper braking methods.

Combination Vehicles

— coupling/uncoupling, jackknife/rollover prevention, following distance, and backing safety.

Hazardous Materials (H)

— classes, placards, shipping papers, loading/unloading, segregation, emergency response, and security.

Passenger (P) & School Bus (S)

— passenger loading/unloading, prohibited practices, rail crossings, emergencies, and student management.

Tankers (N)

— surge/slosh effects, rollover risk, speed on curves, and safe stops/starts.

Doubles/Triples (T)

— converter dollies, coupling order, trailer checks, and rollover/off-tracking control.

Pre‑Trip Inspection

— engine compartment, steering, suspension, brakes, tires/wheels, lights, coupling, cab checks, and emergency equipment.

Required for All CDL Drivers

These tests are mandatory for all Commercial Driver's License applicants

About General Knowledge Tests

Basic rules, regulations, and safe driving practices for commercial vehicles

General Knowledge Test 1

Basic CDL knowledge and traffic laws

📝 50 Questions 🎯 80% to pass
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General Knowledge Test 2

Vehicle safety and inspection procedures

📝 50 Questions 🎯 80% to pass
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General Knowledge Test 3

Driving techniques and hazard awareness

📝 50 Questions 🎯 80% to pass
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General Knowledge Test 4

Transportation of cargo and passengers

📝 50 Questions 🎯 80% to pass
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General Knowledge Test 5

Emergency procedures and vehicle maintenance

📝 50 Questions 🎯 80% to pass
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General Knowledge Test 6

Final comprehensive review test

📝 50 Questions 🎯 80% to pass
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About Air Brakes Tests

Air brake systems, inspection, and operation procedures

Air Brakes Test 1

Basic air brake system components and operation

📝 25 Questions 🎯 80% to pass
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Air Brakes Test 2

Air brake inspection and testing procedures

📝 25 Questions 🎯 80% to pass
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Air Brakes Test 3

Emergency procedures and troubleshooting

📝 25 Questions 🎯 80% to pass
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Air Brakes Test 4

Advanced air brake systems and safety

📝 25 Questions 🎯 80% to pass
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About Pre-Trip Inspection Tests

Vehicle inspection procedures and safety checks

Pre-Trip Inspection Test 1

Engine compartment and cab inspection

📝 20 Questions 🎯 80% to pass
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Pre-Trip Inspection Test 2

Exterior vehicle inspection

📝 20 Questions 🎯 80% to pass
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Pre-Trip Inspection Test 3

Trailer and coupling system inspection

📝 20 Questions 🎯 80% to pass
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Endorsement Tests

Additional certifications for specialized commercial driving

About Combination Vehicles Tests

Tractor-trailers, truck and trailer combinations

Combination Vehicles Test 1

Coupling and uncoupling procedures

📝 20 Questions 🎯 80% to pass
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Combination Vehicles Test 2

Inspection of combination vehicles

📝 20 Questions 🎯 80% to pass
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Combination Vehicles Test 3

Driving combination vehicles safely

📝 20 Questions 🎯 80% to pass
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Combination Vehicles Test 4

Backing and maneuvering techniques

📝 20 Questions 🎯 80% to pass
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Combination Vehicles Test 5

Advanced combination vehicle operation

📝 20 Questions 🎯 80% to pass
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About Hazmat Tests

Hazardous materials transportation and safety

Hazmat Test 1

Hazmat classification and identification

📝 30 Questions 🎯 80% to pass
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Hazmat Test 2

Loading and handling procedures

📝 30 Questions 🎯 80% to pass
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Hazmat Test 3

Documentation and placarding

📝 30 Questions 🎯 80% to pass
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Hazmat Test 4

Emergency response and safety procedures

📝 30 Questions 🎯 80% to pass
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About Passenger Vehicles Tests

Buses and vehicles designed to transport passengers

Passenger Vehicle Test 1

Pre-trip inspection for passenger vehicles

📝 20 Questions 🎯 80% to pass
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Passenger Vehicle Test 2

Loading and unloading passengers

📝 20 Questions 🎯 80% to pass
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Passenger Vehicle Test 3

Passenger safety and emergency procedures

📝 20 Questions 🎯 80% to pass
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Passenger Vehicle Test 4

Special situations and regulations

📝 20 Questions 🎯 80% to pass
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About School Bus Tests

School bus operation and student transportation safety

School Bus Test 1

Loading and unloading students

📝 20 Questions 🎯 80% to pass
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School Bus Test 2

Emergency exits and evacuation procedures

📝 20 Questions 🎯 80% to pass
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School Bus Test 3

Student management and safety

📝 20 Questions 🎯 80% to pass
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School Bus Test 4

Special hazards and situations

📝 20 Questions 🎯 80% to pass
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About Tanker Vehicles Tests

Liquid cargo transportation and tank vehicle operation

Tanker Vehicle Test 1

Tanker vehicle inspection and safety

📝 20 Questions 🎯 80% to pass
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Tanker Vehicle Test 2

Driving techniques for liquid cargo

📝 20 Questions 🎯 80% to pass
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Tanker Vehicle Test 3

Loading, unloading, and emergency procedures

📝 20 Questions 🎯 80% to pass
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About Doubles/Triples Tests

Double and triple trailer combinations

Doubles/Triples Test 1

Coupling and inspection procedures

📝 20 Questions 🎯 80% to pass
Start Test

Doubles/Triples Test 2

Driving techniques and safety

📝 20 Questions 🎯 80% to pass
Start Test

Doubles/Triples Test 3

Emergency procedures and troubleshooting

📝 20 Questions 🎯 80% to pass
Start Test

FAQs — Idaho CDL

Additional certifications for specialized commercial driving

Q1- Who needs a CDL in Illinois?

Drivers of 26,001 lb+ GVWR vehicles, combinations 26,001+ GCWR with a 10,001+ lb trailer, or vehicles carrying 16+ passengers or hazmat.

Q2- Minimum age for CDL in Illinois?

18 intrastate, 21 interstate/hazmat/passenger.

Q3- Do I need a DOT medical card?

Yes, most CDL drivers must hold a valid Medical Examiner’s Certificate before the skills/endorsement tests.

Q4- What is ELDT?

Entry‑Level Driver Training is required for Class A/B and H/P/S endorsements before skills/endorsement tests.

Q5- CLP holding period?

You must hold your CLP at least 14 days before the skills exam.

Q6- Where do I test?

With Illinois Secretary of State (ILSOS) or approved third-party testers.

Q7- Passing score?

80% minimum on each knowledge test.

Q8- Hazmat background check?

Yes — TSA background check plus hazmat knowledge test.

Q9- What to bring on test day?

Driver’s license, CLP, medical card, ELDT proof (if needed), and an appropriate vehicle.