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A trailer inspection form is a document used to carefully inspect a trailer’s technical components and other necessary requirements before being used as a motor carrier. Since trailers are used to carry heavy loads, ensuring that a trailer is in good condition can prevent damage to lives, properties, and businesses.
Trailer inspection forms are used by inspectors that have undergone rigorous training and have been certified by respective government agencies that are in charge of motor carriers. During an inspection, these inspectors are expected to meticulously go through all the inspection procedures and have the authority to command a trailer’s driver or owner to demonstrate some actions dictated in the procedures.
However, transport companies can also carry out regular checks before using trailers in order to avoid failing official inspections.
During a trailer inspection, there are six main technical components that are carefully inspected: brakes, couplings, steering, suspension, frames, and wheels. Although checked individually, these components are interconnected and are dependent on each other. Thus, all of it should be working in good condition.
The information below is referenced from the U.S. DOT Trailer Inspection Form and the U.K. DVSA Inspection Manual.
Stopping a trailer that’s carrying several tons of weight takes a lot of braking force. That is why a trailer has many brake systems in place like surge brakes, parking brakes, and service brakes.
Ensuring that all the brake systems are in good working condition will prevent accidents. In the trailer inspection form, the inspectors are expected to check all types of braking systems. This includes inspecting all of the sub-components as well like the drums, hoses, tubings, and hydraulics.
Also, demonstrations for the braking systems are also needed. For example, the brakes should trigger once the trailer’s coupling disconnects when it is in motion. Another one will be checking if the installed brakes meet the needed calculated braking force. Any noticeable items that need repair will then be noted on the form by the inspector.
Couplings are an essential part of vehicles and connect and transmit power and movement. Trailers have several of these, and inspectors need to check all of them to ensure smooth movement. The inspector must check the fifth wheel, pintle hooks, drawbar, safety devices, and saddle mounts in the trailer inspection form.
During the inspection, it is essential to check first if all the couplings are installed according to the manufacturer’s manual. Then, check if the load-bearing capacity of the couplings matches the load it needs to bear.
Inspectors also check the height of the coupling from the ground and compare it to the manufacturer’s standard. During a stricter inspection, a manufacturer representative can also be present to counter-check. Any substandard installation is recommended for correction and repair.
Not all trailers have steering capabilities. So, this only applies to trailers that have it, and they usually are multi-axle (trailers that have more than one axle).
In the trailer inspection checklist form, the inspector needs to check the steering mechanism's free play. This will be demonstrated with the help of the trailer driver. Then, the inspector would visually check the condition of the steering parts: axles, tie rods, drag links, bearings, joints, and nuts.
There are some cases where it might not be possible to check if a standard is met during the inspection, like needing complete dismantling of the steering mechanisms. During these cases, showing evidence of compliance is enough.
Suspension is the shock absorber system of the trailer, and it helps maintain constant traction between the wheels and the road.
The inspector will check for loose, cracked, deformed, or missing u-bolts, spring hangers, and other axle positioning parts with the trailer inspection checklist. If any issues are found, the inspector will then make a note and immediately recommend repairing or replacing these parts.
The frame is the main body of the trailer. This is where all other components are connected and where the payload is placed.
During the trailer inspection, the inspector will carefully inspect all the frame members. The objective is to check if the overall structural integrity of the frame is still good.
Next is checking if there is enough clearance between the tires and wheels. And if all the subframes or axle assemblies on the frame are in good working condition. If any issues are found on the frame, major repairs are needed.
Tires and wheels are what enable trailers to move. When in good condition, the transmission of movement will be very efficient.
In the trailer inspection checklist, tires should be checked for wear and tear. The tire carcass should also be checked if it matches the intended use. On the wheel side, the inspector will check the condition of the locks, side rings, rims, fasteners, and welds.
Aside from the very technical side of a trailer inspection, there will be two other non-technical items that will be needed during the inspection. Please take note that this may vary from country to country.
On the DOT trailer inspection checklist, they are requiring two identifying documents to be presented to the inspectors: Vehicle Identification Number (VIN) and license plate.
A vehicle identification number (VIN) is a unique number that identifies a trailer upon registration. It contains essential information like the manufacturing location, manufacturer, car brand, and model.
In some countries, it’s enough that the license plate for a trailer is the same as the vehicle that’s towing it. But some countries require separate registration for a trailer license plate.
Due to being a bulky vehicle, a trailer has many blind spots and can easily be bumped by other vehicles. That is why lighting and marking are an essential part of a trailer. Although guidelines may vary depending on the country, it’s common that all markings must be reflectorized, and all lightings should cover all the blind spots of the trailer.
Regular inspections help transportation companies ensure that their trailers are ready for the road. In this way, they prevent defects that endanger drivers, transportation, and the public and lead to trailers being taken out of service. Numerous companies still perform their trailer inspections with paper and pencil - but that doesn't have to be the norm anymore.
Why not also rely on digital solutions for trailer inspections? The app for audits and inspections from Lumiform, for example, allows you to convert all your paper lists into digital checklists. You and your drivers can then easily access them via mobile devices and fill them out directly on the spot. But that's not the only advantage a trailer inspection app offers you: