Vehicle Controls, Handling, and Pre-Trip Inspection
What you must know
A pre-trip inspection is a documented, systematic walk-around. Know the inspection sequence and the items in each zone: engine compartment (fluid levels, belts, hoses, steering components, brake lines), coupling system (fifth wheel, kingpin, locking jaws, safety latch, air lines, electrical cord), and the vehicle exterior (tires, wheels, lug nuts, rims, brakes, lights, reflectors, mud flaps, frame, exhaust). Inside the cab, check gauges, warning lights, seat belt, horn, wipers, mirrors, and the parking brake. After starting, check air pressure build-up and listen for leaks; know that a loss of air pressure triggers the low-air warning and eventually the spring brakes apply automatically.
Handling concepts include the effect of load on center of gravity, the risk of rollover in high-speed turns, and the physics of braking. Commercial vehicles with air brakes need time to build pressure, and brake fade on long downgrades is managed by gearing down before the descent, not by riding the brakes.
Traps to expect
Questions test whether you know the difference between a warning and a failure. A low-air warning is not the same as a brake failure; the spring brakes engage when pressure drops too low, which is a safety feature. Tire questions reward checking tread depth, sidewall condition, and proper inflation, and they penalize the idea that a visibly inflated tire is necessarily safe. Coupling questions reward confirming the locking jaws are closed and the tug test is performed.
Rule of thumb: inspect in a fixed order every time, front to back, and never skip the coupling check. A missed kingpin is a catastrophic failure, not a minor one.