CDL Knowledge Examination Practice

Illinois Commercial Driver’s License (CDL) Knowledge Examination Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the main purpose of a pre-trip inspection?
• To check the cleanliness of the vehicle
• To ensure the vehicle is safe to operate
• To fill out logbooks
• To practice driving skills

Rationale: Pre-trip inspections help identify safety issues before

driving to prevent accidents.

• Which of the following is a required endorsement for transporting

hazardous materials?

• Passenger 1 / 4

• School Bus
• Hazardous Materials (H)
• Tanker

Rationale: The H endorsement is legally required to transport

hazardous materials.

3. When backing a truck, you should:

• Use only your mirrors
• Have a helper guide you whenever possible
• Honk continuously
• Turn the steering wheel quickly

Rationale: A helper provides guidance to prevent collisions since

large trucks have blind spots.

• How often must you check your mirrors while driving?
• Every 5 minutes
• Every 10 minutes
• Regularly to maintain awareness of surrounding traffic
• Only when changing lanes

Rationale: Frequent mirror checks allow drivers to see hazards and

traffic changes.

• What is the proper way to brake when driving a manual transmission

vehicle on a downgrade?

• Use the brakes only
• Use engine braking along with service brakes 2 / 4

• Coast to save fuel
• Shift into neutral

Rationale: Engine braking reduces wear on service brakes and helps

maintain control.

• Which factor most affects stopping distance?
• Color of the vehicle
• Roadside signs
• Speed of the vehicle
• Type of fuel used

Rationale: Higher speeds require longer distances to stop safely.

• What should you do if your brakes fail while driving downhill?
• Pump the brakes
• Use the emergency brake and downshift
• Turn off the engine
• Steer off the road immediately

Rationale: Downshifting and using the emergency brake can help

slow the vehicle safely.

• How should hazardous materials be loaded on a vehicle?
• Randomly
• Securely and according to regulations
• Only on the top
• Only in the center

Rationale: Proper loading prevents shifting, spills, and accidents. 3 / 4

• Which of these is true about speed management?
• You should drive as fast as possible to reach your destination
• Adjust speed according to traffic, road, and weather conditions
• Follow the posted speed limit exactly under all conditions
• Speed limits don’t apply in heavy traffic

Rationale: Safe speed depends on conditions, not just posted limits.

• What does a “No-Zone” refer to?
• Areas of the road without traffic signs
• A restricted parking area
• Blind spots around large trucks
• Speed enforcement zones

Rationale: “No-Zones” are large blind spots where the driver cannot

see other vehicles.

• What is the correct hand signal for a left turn?
• Left arm down
• Left arm straight out
• Left arm bent upward
• Right arm bent upward

Rationale: Standard hand signals help communicate intentions when

signals fail or are not used.

12. When approaching a railroad crossing without signals, you must:

• Slow down and look for trains
• Stop only if you see a train
• / 4