DOT Commercial Vehicle Inspection Standards 2

Question 1

Under FMCSA regulations, what is the minimum tread depth required for front steering axle tires on a commercial vehicle?

Accepted Answer

4/32 inch

Answer

Front steering axle tires must have a minimum tread depth of 4/32 inch, while other tires require at least 2/32 inch.

Question 2

During a brake inspection, a CMV is found to have 25% of its service brakes out of adjustment. What action should the inspector take?

Accepted Answer

Place the vehicle out of service immediately

Answer

A vehicle is placed out of service if 20% or more of its service brakes are defective or out of adjustment.

Question 3

Which federal regulation establishes the out-of-service criteria for commercial motor vehicles during roadside inspections?

Accepted Answer

49 CFR Part 393

Answer

49 CFR Part 393 covers parts and accessories necessary for safe operation and forms the basis for OOS criteria.

Question 4

What is the maximum allowable slack adjuster travel (pushrod stroke) for a Type 30 brake chamber at a 90 psi application?

Accepted Answer

2.0 inches

Answer

For a Type 30 brake chamber, the maximum pushrod stroke at 90 psi is 2.0 inches before the brake is considered out of adjustment.

Question 5

A commercial vehicle's frame has a crack running perpendicular to the vehicle's length. This condition is considered:

Accepted Answer

An out-of-service defect

Answer

Any crack in the vehicle frame is an out-of-service condition regardless of length or load status.

DOT Inspector Certification Practice Test