Perform Pre-Trip Inspection and Vehicle Readiness Checks
What this domain tests
A systematic pre-trip inspection that proves the tractor, trailer, coupling, brakes, cargo and documents are fit before the wheels turn.
Core rules
- Start with documents: licence, OR/CR, insurance, trip ticket, bill of lading, cargo seal. Then walk the combination in a fixed order so nothing is skipped.
- Coupling: fifth-wheel jaws closed around the kingpin, no gap between plate and trailer, release handle safety-latched, air lines and electrical cord connected and not chafing, landing gear fully raised, mud flaps secure.
- Air brakes: build to governor cut-out, engine off, observe initial pressure drop (generally not more than 3 psi/min for a single unit and 4 psi/min for a combination), then apply and hold the brakes and check for a further leak.
- Tires: correct cold pressure, tread depth, cuts, bulges, missing lug nuts, dual spacing. Lights: head, tail, brake, turn, hazard, marker, reverse, plate.
- Cargo: weight within axle limits, secured to rated capacity, tarped if required, nothing loose.
Worked example
After coupling, you apply the trailer parking brake and gently pull against it. The tractor moves and the trailer does not - that is a failed tug test. Reasoning: the trailer brakes are holding, so the tractor is pulling out from under the kingpin, which means the jaws are not locked. Stop, set the tractor brake, get out, inspect the jaws and kingpin, recouple and repeat. A visual check alone can miss a high or misaligned kingpin.
Traps
- Skipping the walk-around because the truck was fine yesterday.
- Checking lights without a second person and assuming trailer markers work.
- Not checking under the trailer for air leaks, oil or hanging lines.
- Forgetting the fire extinguisher, chocks and spare.
- Doing the tug test with the trailer brakes released.