Free dot trailer inspection checklist

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Free DOT trailer inspection checklist (PDF-ready). Covers FMCSA 49 CFR 396 coupling, brakes, lights, tyres, suspension, frame and cargo. Download free.

Last updated: 2026-04-27

Jarrod Milford

Commercial Director

Updated 27 April 2026

How to use: download the PDF, print or complete digitally on any device.

• ✓PDF format, ready to print or fill on screen
• ✓Use as-is or customise to suit your operation
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Benefits of using this dot trailer inspection checklist

• FMCSA compliance: documented trailer inspections meet 49 CFR 396 requirements for vehicle condition and maintenance records, supporting DOT audit readiness.
• Reduced out-of-service rates: the checklist covers the most common trailer violations found during CVSA roadside inspections, including brakes, lights and tyres, helping identify and correct them before a stop.
• Brake system safety: dedicated brake inspection items cover slack adjuster stroke, air leaks, drum condition and lining thickness, which are the most frequent out-of-service violations for trailers.
• Coupling integrity: inspecting the kingpin, fifth wheel, locking jaws, glad hands and safety chains helps prevent separation incidents, one of the most catastrophic trailer-related failures.
• Improved CSA scores: consistent trailer inspections and defect correction improve your carrier Compliance, Safety, Accountability (CSA) BASIC scores, particularly in the Vehicle Maintenance category.
• Cargo securement verification: the checklist includes cargo securement items to confirm that loads are properly restrained, reducing the risk of load shifts and spills.

How to use this dot trailer inspection checklist

1. Record the trailer details, inspector details and date. If performing a pre-trip inspection, also record the power unit information and coupling status.: Enter the trailer unit number, VIN, year, make, type (dry van, flatbed, reefer, tanker), registration, carrier name and current odometer or hub mile reading. Note the inspection location and whether this is a pre-trip, 90-day or annual inspection. If coupled, record the tractor unit number.
2. Inspect the coupling area: check the kingpin for wear and cracks, inspect glad hand seals and connections, check air and electrical lines for leaks, rubbing and proper connection, and confirm safety chains or cables are in place.: Examine the kingpin for visible wear, mushrooming or cracks. From the tractor side, verify the fifth wheel plate is greased, the locking jaws are fully engaged and the release handle is seated. Check each glad hand seal for cracks and confirm both air line connections are secure with no audible leaks. Inspect the electrical pigtail connector for bent or corroded pins and confirm all trailer lights illuminate when connected.
3. Inspect the brake system: have someone apply the trailer brakes while you check each wheel for brake function. Measure slack adjuster stroke with brakes applied (must be within FMCSA limits). Inspect brake drums, linings, hoses, tubing and valves. Verify ABS indicator light.: With the engine running and air system fully charged, pull the trailer air supply knob to apply trailer brakes. At each wheel, mark the pushrod position at rest and at full application, then measure the stroke. For a Type 30 chamber the maximum applied stroke is 2 inches. Inspect each brake drum for cracks, scoring or heat discoloration. Check lining thickness against manufacturer minimums. Trace air hoses and tubing for chafing, leaks and proper securing. Confirm the ABS indicator on the dash cycles correctly at startup.
4. Walk around the trailer and check all lights and reflectors. Have someone activate turn signals and brake lights while you observe from the rear and sides. Check reflective tape (conspicuity markings) on both sides and rear.: Verify that tail lights, brake lights, turn signals, clearance lights (front and rear), side marker lights and the licence plate light all illuminate correctly. Inspect conspicuity markings (reflective tape) on both sides and the rear per FMCSA requirements. Confirm all reflectors are clean, unbroken and securely mounted. Replace any burned-out bulbs or cracked lenses before departure.
5. Inspect tyres on each axle: check tread depth (minimum 2/32 inch), inflation, condition and matching. Check lug nuts, hub seals and rim condition.: Use a tread depth gauge to confirm every tyre meets the 2/32-inch minimum in at least two adjacent major grooves. Check inflation by visual inspection or tyre gauge against the manufacturer rating on the sidewall. Look for cuts, bulges, exposed cord, flat spots and sidewall damage. Confirm tyres on each axle are the same size and type. Check that all lug nuts are present, torqued to specification and free of rust streaks that indicate loosening. Inspect hub seals for oil leaks and rim flanges for cracks or dents.
6. Inspect the suspension (springs or air bags, U-bolts, hangers), frame (rails, crossmembers, welds), body (floor, sides, roof, doors), and landing gear (crank, legs, pads).: Check leaf springs for broken, shifted or missing leaves. For air-ride trailers, inspect air bags for cracks, leaks and proper inflation. Verify U-bolts and hangers are tight with no visible cracks. Walk the length of both frame rails looking for cracks, corrosion holes or broken welds on crossmembers. For enclosed trailers, check floor integrity by walking the full length, inspect side panels and roof for damage, and test all doors and seals for proper operation. Operate the landing gear crank to confirm smooth travel and check gear legs and pads for structural damage.
7. If loaded, inspect cargo securement: verify the number and condition of tie-downs meet FMCSA requirements for the commodity, check load distribution and confirm securement devices are in serviceable condition.: Count the tie-downs and compare against FMCSA 49 CFR 393.106 requirements based on the length and weight of the load. Inspect each strap, chain and binder for cuts, fraying, kinks and proper working load rating. Confirm the load is centred between the axles and does not exceed axle weight limits. Check that dunnage, blocking and bracing prevent lateral and longitudinal movement. For flatbed loads, verify edge protection is used where straps contact sharp edges.
8. Record any defects and determine whether the trailer is safe to operate. Out-of-service defects (per CVSA criteria) must be corrected before the trailer is moved. Sign and date the checklist.: Document each defect with a description, severity rating (out-of-service or repairable) and the corrective action taken or required. Reference the applicable FMCSA regulation or CVSA out-of-service criterion for each item. If any out-of-service condition exists, the trailer must not be moved until repaired. Have the inspector and driver both sign and date the completed checklist. Upload or file the record per your carrier document retention policy.

In MapTrack, you can track your fleet with gps and digital pre-starts. Each submission is stored as a timestamped PDF against the asset record.

Frequently asked questions

What does FMCSA 49 CFR 396 require for trailer inspections?

FMCSA 49 CFR 396 requires that trailers, like all commercial motor vehicles, be maintained in safe operating condition. Under 49 CFR 396.13, the driver must be satisfied that the trailer is safe before each trip and must review the previous DVIR. Under 49 CFR 396.17, trailers must receive an annual periodic inspection by a qualified inspector covering the criteria in Appendix G. Under 49 CFR 396.3, carriers must have a systematic inspection, repair and maintenance programme for all vehicles including trailers. Failure to maintain trailers results in roadside out-of-service orders and impacts the carrier CSA Vehicle Maintenance BASIC score.

What are the most common trailer violations at roadside inspections?

The most common trailer violations found during CVSA roadside inspections include brake adjustment (slack adjuster stroke out of limits), brake components (worn linings, cracked drums, air leaks), lighting (inoperative tail lights, brake lights, turn signals or clearance lights), tyre condition (tread depth below minimum, flat tyres, exposed cord), reflective tape (missing or damaged conspicuity markings), and cargo securement (insufficient or defective tie-downs). Many of these are out-of-service violations that prevent the trailer from continuing until repaired.

How do I measure trailer brake slack adjuster stroke?

To measure slack adjuster stroke, have someone make a full brake application while you are under the trailer at the wheel. Mark the pushrod at the brake chamber with the brakes released, then mark it again with the brakes fully applied. Measure the distance between the two marks. This is the applied stroke. Compare the measurement to the FMCSA brake adjustment limits, which vary by brake chamber size (e.g. Type 30 chamber has a maximum stroke of 2 inches for standard brakes). If the stroke exceeds the limit, the brakes are out of adjustment and the trailer is out of service.

What is the minimum tyre tread depth for trailers?

Under FMCSA regulations, the minimum tyre tread depth for trailer tyres is 2/32 of an inch (approximately 1.6 mm) in any two adjacent major tread grooves at any location on the tyre. Tyres on the steer axle of the power unit have a higher minimum of 4/32 inch, but trailer tyres are held to the 2/32 standard. Tyres with tread depth below the minimum, or with exposed cord, sidewall damage or flat spots, are out-of-service violations. Check all tyres on every axle during the pre-trip inspection.