How to Do a Pre Trip Inspection

This checklist shows you how to do a pre-trip inspection on a tractor-trailer, following the outside inspection portion of the CDL road test that changed in 2023. There is no required order for the inspection — you may follow your examiner's preferred flow or build your own sequence, as long as every item below is covered. Every truck differs, especially in the engine compartment, so adapt each check to the specific vehicle you are inspecting. Before you begin, have the vehicle's inspection checklist, a tire gauge, and a rag or towel for checking dipsticks on hand.

Vehicle Details

Record the identifying information for the specific tractor-trailer you are inspecting before starting the walk-around, since layout and component placement can vary from truck to truck.

Field	Entry
Vehicle ID
Mileage
Route/Run
Depot
Operator
Inspection Time

The walkthrough does not capture specific data-entry values for vehicle ID, mileage, route, depot, operator, or inspection time — log these from your dispatch record or work order before you start the inspection.

Exterior Checks

Checking front lights and body condition

Begin the inspection at the front of the vehicle and confirm that every exterior light is operational and correctly mounted.

Item	Inspection criteria	Pass	Fail	N/A
Clearance lights (top of cab)	Operational, proper color lens, not cracked, mounted securely
Headlights	Operational, proper color lens, not cracked, mounted securely
Turn signals	Operational, proper color lens, not cracked, mounted securely
High beams	Operational, proper color lens, not cracked, mounted securely

Checking for leaks and vehicle stance

Look underneath the vehicle for fluid leaks and confirm the truck is sitting level.

Item	Inspection criteria	Pass	Fail	N/A
Under-vehicle leaks	No puddles or dripping fluid from engine or transmission
Vehicle stance	Not leaning left, right, front, or back (indicates suspension issue)

Accessing and inspecting the engine compartment

Release the hood latches on both sides of the vehicle, open the hood carefully, and secure it in the open position before inspecting the components underneath.

Fluid levels — with the engine off, unscrew each cap, pull out the dipstick, wipe it clean, reinsert it fully, then remove it again to read the level.

Item	Inspection criteria	Pass	Fail	N/A
Engine oil level	Level falls between the "add" and "fill" lines on the dipstick
Power steering fluid level	Fluid at proper operating level
Coolant level	Proper level visible on reservoir; never open cap when engine is hot; reservoir not cracked, damaged, or leaking, and securely mounted

Hoses and steering components

Item	Inspection criteria	Pass	Fail	N/A
Engine compartment hoses	Securely mounted, no leaks
Power steering box	Securely mounted, not damaged or broken, no loose or missing nuts/bolts, no leaks
Steering linkage (arm, link, rod)	Not worn, cracked, or loose; joints and sockets secure with no missing nuts, bolts, or cotter keys; no leaks, all connections tight

Checking front tires and wheels

Move to the front tire area and inspect the tread, inflation, valve stem, and lug nuts.

Item	Inspection criteria	Pass	Fail	N/A
Tread depth (steering axle)	No less than 4/32 inch, evenly worn, no cuts, bulges, or exposed cords
Tire inflation	Between 90 and 100 PSI, checked with a tire gauge
Mounting	Properly inflated and mounted securely
Valve stem	Mounted securely, no damage or looseness
Lug nuts	All present, in good condition, not distorted or damaged, no rust trails or shiny threads indicating looseness

Checking brakes

Inspect the brake hoses, lines, and contact surfaces for damage or contamination.

Item	Inspection criteria	Pass	Fail	N/A
Brake hoses and lines	Securely mounted, no leaks or visible damage
Brake contaminants	No oil, grease, or debris between drum and brake shoes, or between disc brake components

Checking suspension (front)

Item	Inspection criteria	Pass	Fail	N/A
Spring hangers	No loose or missing nuts or bolts
Shock absorbers	Securely mounted, not damaged or leaking
Bushings	Present and in good condition, no excessive wear, cracks, or missing bushings

Checking cab exterior lights, reflectors, and mirrors

Item	Inspection criteria	Pass	Fail	N/A
Turn signal and other cab lights	Securely mounted, clean, not cracked, functioning properly
Reflectors	Present, clean, not cracked, securely mounted
Mirrors	Securely mounted, no loose or broken fittings, clean and not cracked

Checking fuel tank and battery box

Item	Inspection criteria	Pass	Fail	N/A
Fuel tank	Securely mounted, not leaking
Battery box	Securely mounted (no need to open the box, but check its condition)
Batteries and lines	Batteries secure inside the box, no excessive corrosion on the lines, lines properly connected and in good condition

Checking the frame and coupling area between tractor and trailer

Move to the area between the tractor and trailer to inspect the frame and connection components.

Item	Inspection criteria	Pass	Fail	N/A
Frame (between tractor and trailer)	No broken or cracked areas on the large metal frame component
Trailer tandem release lever	Securely mounted, not damaged
Air and electric lines	Securely connected at both ends, not cut, chafed, spliced, or worn, no tape on the lines
Line connection points	Hard-wired or hard-plugged and secure
Line routing	Not tangled, pinched, or dragging against tractor parts; safely routed and free from obstructions

The fifth wheel skid plate is the main coupling surface between tractor and trailer, and it is critical for coupling; it must be inspected for damage or excessive wear as part of the coupling review. In real-world operation, thoroughly check every coupling and connection point for safety, beyond the specific items covered during a test.

Checking rear tires, rim, brakes, and rear suspension

Rear tires may encounter obstacles that the front tires do not, so give them the same thorough review.

Item	Inspection criteria	Pass	Fail	N/A
Tread and sidewalls	Evenly worn, no cuts or damage on tread, no bulges, cuts, or bubbles on sidewalls
Tire inflation	Between 90 and 100 PSI, checked with a tire gauge
Valve stem and cap	Not leaking, securely mounted
Rim	Not welded, damaged, or bent; bolt holes not elongated; securely mounted to tire
Lug nuts and studs	All present, no looseness (rust trails or shiny threads), studs not distorted or damaged, bolt holes and studs in good condition
Brakes (behind tire)	Hoses and lines securely mounted, not leaking, free from damage, cuts, or frays; area free from contaminants between drum and shoes or disc brake components
Rear suspension	Leaf springs not missing, shifted, cracked, or broken; spring hangers or mounts securely mounted

Checking the fifth wheel assembly

Move beneath the trailer, near the landing gear and fifth wheel assembly, to review the coupling mechanism in detail.

Item	Inspection criteria	Pass	Fail	N/A
Fifth wheel skid plate	No damage, properly lubricated
Kingpin, apron, and gap	Present, undamaged, properly aligned
Apron	No cracks, bends, or other visible damage
Lubrication	All contact surfaces between skid plate, kingpin, and apron adequately lubricated
Locking jaws	Fully closed around the kingpin, no play or gap between jaws and kingpin
Release arm	In the engaged position with the safety latch in place

Discuss and check every component under the trailer during your review, and be thorough about mentioning each part you inspect.

Checking landing gear and tandem axle

Do not skip these steps or make excuses to avoid a proper inspection of the landing gear and tandem components.

Item	Inspection criteria	Pass	Fail	N/A
Landing gear	Not damaged, securely mounted, operates properly
Clearance (landing gear to axle)	Enough space between landing gear and axle to prevent contact during turns
Clearance under trailer	Sufficient clearance confirmed
Tandem release lever	Intact, secure, no missing parts
Tandem pins	Present, properly seated, securely mounted

Checking rear lights

Move to the rear of the trailer to inspect all rear-facing lights.

Item	Inspection criteria	Pass	Fail	N/A
Rear clearance and marker lights	Operational, proper condition, checked top and bottom

Checking rear doors

Stand at the rear of the trailer, confirm the door locking mechanism is engaged, and verify the door opens and closes properly from the outside.

Item	Inspection criteria	Pass	Fail	N/A
Rear door lock	Locking mechanism engaged, door opens and closes properly

Interior Checks

The walkthrough covers only the exterior of the tractor-trailer; it does not address interior items such as seats, flooring, handrails, HVAC, fare equipment, cameras, cleanliness, or accessibility equipment — record those checks according to your fleet's separate interior inspection procedure.

Safety Equipment

The walkthrough does not cover onboard safety equipment such as the fire extinguisher, first aid kit, warning triangles, radio, emergency exits, or alarms — verify these items against your fleet's dedicated safety-equipment checklist.

Defects and Restrictions

The walkthrough does not define formal defect-severity categories, a roadworthy determination, or an escalation process — establish these definitions in your fleet's maintenance policy. However, several items covered above are treated as critical to passing inspection and should be flagged immediately if they fail:

• Leaks anywhere under the vehicle, in the engine compartment, or around the brakes.
• A vehicle that is leaning to any side, indicating a possible suspension problem.
• Loose, cracked, or worn steering linkage, or a damaged power steering box.
• Tread depth below 4/32 inch, or tire inflation outside the 90–100 PSI range.
• Lug nuts showing rust trails or shiny threads, indicating looseness.
• Damage to the fifth wheel skid plate, kingpin, apron, locking jaws, or release arm.
• Missing or insecure tandem pins, or a damaged tandem release lever.
• Air or electric lines that are cut, chafed, spliced, worn, or improperly routed.

Any item marked "Fail" above should be documented and addressed before the vehicle is placed in service.

Operator and Maintenance Sign-Off

The walkthrough does not include a formal sign-off process with signatures, timestamps, or work order references — capture this information according to your fleet's documentation standard once the checklist above is complete. Confirm which exact inspection script or phrasing your local test site or company requires, since wording can vary by examiner or location.

Study every inspection step thoroughly using the required script for your location, since this preparation is what determines whether the pre-trip inspection portion is passed.

For hands-on training support in preparing for a CDL road test, Driving Academy is available at 908-525-3609 or cdldrivingacademy.com.

Sign-off field	Entry
Operator signature
Date/timestamp
Maintenance sign-off
Work order reference