CDL Commercial License Prep Exam Questions & Answers 2026 (1–10)

Question 1

During a pre-trip inspection, which tire condition would most likely cause a vehicle to be placed out of service?

TheoryPractice · Accepted Answer

Tread depth below 2/32 inch on steering tires. Tread depth below 2/32 inch on steering tires is a critical safety violation that would place a commercial vehicle out of service, as it significantly increases the risk of blowouts and loss of vehicle control.

Question 2

What is the proper method for checking brake adjustment on a commercial vehicle?

TheoryPractice · Accepted Answer

Measure the pushrod travel when brakes are applied. The correct method for checking brake adjustment is to measure the pushrod travel when brakes are applied, which determines if the brakes are properly adjusted for optimal stopping performance.

Question 3

Which of the following is NOT a required item to check during a steering component inspection?

TheoryPractice · Accepted Answer

Navigation system functionality. While steering components must be thoroughly inspected, the vehicle's navigation system is not part of the required steering component inspection as it doesn't affect the mechanical operation of the steering system.

Question 4

When inspecting air brake slack adjusters, what is the maximum allowable free play for most commercial vehicles?

TheoryPractice · Accepted Answer

1/4 inch. The maximum allowable free play for most commercial vehicle slack adjusters is 1/4 inch, beyond which brake performance would be compromised and could result in an out-of-service violation.

Question 5

Which emergency equipment item is NOT typically required to be carried on a commercial motor vehicle?

TheoryPractice · Accepted Answer

First aid kit. While fire extinguishers, warning triangles, and spare fuses are required emergency equipment items, a first aid kit is not federally mandated equipment for all commercial motor vehicles (though it is recommended).

Question 6

What condition would make headlights fail inspection?

TheoryPractice · Accepted Answer

Different colored headlights. Different colored headlights would fail inspection as they violate regulations requiring matched, properly colored lights for visibility and to avoid confusing other drivers.

Question 7

During a cargo securement inspection, which of the following would indicate a violation?

TheoryPractice · Accepted Answer

Cargo shifting more than 1 inch in any direction. Cargo shifting more than 1 inch in any direction indicates inadequate securement, which violates safety regulations and creates a serious hazard for safe vehicle operation.

Question 8

What is the minimum tread depth requirement for non-steering tires on a commercial vehicle?

TheoryPractice · Accepted Answer

1/32 inch. The minimum legal tread depth for non-steering tires on a commercial vehicle is 1/32 inch, though many safety experts recommend more than the minimum for optimal safety.

Question 9

What should you check on windshield wipers during a pre-trip inspection?

TheoryPractice · Accepted Answer

Proper tension against the windshield. During a pre-trip inspection, you should check that windshield wipers have proper tension against the windshield to ensure they can effectively clear precipitation for safe visibility.

Question 10

When inspecting a vehicle's suspension system, which of the following would be considered a critical defect?

TheoryPractice · Accepted Answer

Cracked or broken leaf spring. A cracked or broken leaf spring is considered a critical defect during suspension inspection as it can lead to complete suspension failure, loss of vehicle control, and potentially serious accidents.

CDL Commercial License Prep Exam Questions & Answers 2026 (1–10)

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