The pre-trip inspection is one of the most important responsibilities of a CDL driver and a required component of both the written test and the skills test. Federal regulations require a thorough vehicle inspection before every trip.
A proper pre-trip covers the engine compartment (fluid levels, belts, hoses, leaks), the cab interior (gauges, controls, safety equipment), the vehicle exterior (tires, wheels, lights, reflectors, body condition), and coupling devices if pulling a trailer.
You must be able to identify defects that would make the vehicle unsafe to operate. Items that require immediate attention include steering defects, brake problems, tire damage, lighting failures, and coupling problems. The DMV test will assess your systematic inspection knowledge.