Vehicle Inspection
What this domain tests
Vehicle Inspection tests the pre-trip, en-route, and post-trip inspection a CDL driver must perform and document. The exam asks what to check, how much tire tread is legal, how to spot brake defects, and when to place a vehicle out of service.
Core rules
- Do a pre-trip inspection before each shift; check lights, tires, wheels, brakes, steering, coupling, cargo securement, and emergency equipment.
- Front steer tires need at least 4/32 inch of tread; all other tires need at least 2/32 inch. Look for cuts, bulges, exposed cord, and mismatched duals.
- Check brake adjustment and watch for air leaks, cracked drums, damaged hoses, and missing slack adjuster pins.
- Inspect the engine compartment for fluid leaks, belt condition, and secure battery mounting.
- Report defects in writing and do not drive a vehicle that is unsafe or out of service.
Worked example
A steer tire measures 3/32 inch in the center groove. The minimum for a front steer tire is 4/32 inch, so the vehicle fails inspection even though 3/32 inch would pass on a rear tire. The reasoning: steer tires carry steering and much of the braking load, so the standard is stricter.
Traps
Checking only one side of the vehicle; measuring tread at the edge instead of the center groove; missing a cracked brake drum because the wheel is dirty; and assuming a post-trip inspection is optional.