Pre-trip inspection practice test
The vehicle inspection is the first scored section of the CDL skills test, and the air brake sequence inside it is the part that fails candidates. These questions cover the figures and the order the examiner expects — tread depths, leak limits, coupling checks, and what you have to say out loud.
Inside the cab, the pre-trip checks include:
How the inspection test works
On the skills test you walk the vehicle with the examiner beside you. You point to or touch each component, name it, and say what you are checking for. Items you inspect silently score nothing — the test measures what you demonstrate, not what you notice.
The vehicle you test in sets your license. No air brakes on the test vehicle means an air-brake restriction on the CDL; a straight truck instead of a combination means no Class A. Test in the vehicle you intend to drive.
What the questions cover
The bank follows the federal manual sections every state scoresheet is built from:
- The seven-step method, from the vehicle overview to the brake check
- Tires and wheels: 4/32" steer tread, 2/32" elsewhere, rust trails, rim damage
- Suspension, steering play, belts, fluids, exhaust, and frame
- Lights and reflectors — colors, and how to check them alone
- Coupling: fifth wheel gap, locking jaws, landing gear, glad hands
- The brake checks: hydraulic, parking, service, and the full air sequence (leak limits, 60 psi warning, 20–45 psi spring brakes)
The checklist, zone by zone
Same order examiners expect. Full explanations in the pre-trip inspection guide.
1 · Engine compartment
- Fluid levels: oil, coolant, power steering — and no leaks underneath
- Belts and hoses: no cracks, frays, or ballooning
- Steering components: no loose or missing nuts, no play in linkage
- Front suspension and brakes: springs, shocks, hoses, drum/pads condition
2 · Cab check and engine start
- Seatbelt, mirrors, and clean windshield with working wipers
- Gauges: oil pressure rising, air pressure building, voltmeter charging
- Horn (city and air), heater/defroster, lighting indicators
- Parking brake check: does the tractor hold against a gentle pull?
3 · Lights and reflectors
- Headlights high/low, turn signals, four-way flashers, brake lights
- Clearance lights and reflectors — clean, intact, correct color
4 · Walkaround: wheels, tires, and body
- Tires: tread depth (4/32" steer, 2/32" elsewhere), no cuts or bulges, proper inflation
- Rims and lug nuts: no cracks, rust trails, or shiny threads (signs of looseness)
- Hub oil seals and axle seals: no leaks
- Frame, crossmembers, and mudflaps: no cracks, bends, or missing parts
5 · Coupling (combination vehicles)
- Fifth wheel: locking jaws closed around the kingpin, no gap between plates
- Air and electrical lines: secure, no rubbing, glad hands sealed
- Landing gear fully raised, handle secured
6 · Trailer
- Doors, hinges, and cargo securement
- Trailer lights, reflectors, and mudflaps
- Trailer suspension, brakes, and tires — same standards as the tractor
7 · Air brake check (the make-or-break)
- Static leak test: pressure drop under 4 psi in one minute (combination)
- Low air warning activates before 60 psi
- Tractor protection valve pops between roughly 20–45 psi
- Spring brakes engage; service brake test — vehicle stops firmly, no pulling
Frequently asked
- Is the pre-trip inspection a written test?
- No — it is the hands-on first section of the CDL skills test. But the facts it scores (tread depths, leak rates, warning pressures) are the same ones the written knowledge tests ask, which is why practicing them as questions works.
- How long does the pre-trip inspection test take?
- Plan for 25–45 minutes. Examiners are scoring method and completeness, not speed — the same route around the vehicle every time is what keeps you from skipping an item under nerves.
- What fails people most often on the pre-trip?
- The air brake check. In most states a failed air brake sequence fails the whole inspection regardless of the rest. Drill the order until it is automatic: cut-out, leak test, low-air warning, spring-brake pop, then the parking and service brake tests.