DOT Trailer Inspection Requirements for First-Time Trailer Owners

The Transwest Team
The Transwest Team
Jan 04, 2021
DOT Trailer Inspection

For first-time trailer owners, understanding the legal requirements involved with the use of a trailer is an important initial step. One of the key things to be aware of is the need to pass a Department of Transportation (DOT) trailer inspection. 

DOT is the official authority on all things related to transportation safety in the United States. According to their mission statement, the DOT exists to ensure that America has the safest, most efficient, and most modern transportation system in the world. Upholding that mission means rigorous safety standards for trucks and trailers weighing more than 10,000 pounds.

Before purchasing a trailer, be sure you are prepared to adhere to the DOT’s guidelines. In this article, we'll walk you through the DOT trailer inspection requirements and offer a helpful checklist and additional resources for further reading. 

What Are DOT Inspections?

Any commercial motor vehicle that surpasses 10,000 pounds in weight is required to pass a DOT inspection every year. This annual inspection is conducted by the DOT, often by a DOT inspector or a state police officer. 

While DOT inspections are often associated with commercial trucks, trailers must also adhere to specific requirements. Any trailer over 10,000 pounds must maintain a separate DOT safety rating apart from the vehicle’s safety rating, according to, an organization focused on training commercial truck drivers, The only exception is for trailers less than 10,000 pounds that are specifically for personal use. 

How Often Do DOT Inspections Take Place?

Trailers that require DOT inspections must be inspected a minimum of once a year, though inspections can take place even more frequently.

In some cases, roadside DOT inspections will be required. These roadside stops will require your trailer to meet the same safety standards as an annual, scheduled inspection. 

DOT Trailer Inspection Requirements Checklist

According to the U.S. Department of Transportation’s Federal Motor Carrier Safety Administration (FMCSA), the following items on the DOT trailer inspection checklist will be reviewed to ensure that your equipment is operating as intended:

  • Brake connections
  • Brakes
  • Coupling chains
  • Coupling (king) pin
  • Doors
  • Hitch
  • Landing gear
  • Lights
  • Roof
  • Springs
  • Tarpaulin
  • Tires
  • Wheels

Keep in mind that this list applies only to items found on the trailer section of this annual inspection report. The vehicle towing the trailer must meet a separate list of requirements. Speak to your local DOT authority to learn more about all safety requirements prior to submitting your commercial vehicle to an annual inspection.

Additional Frequently Asked Questions About Trailer Inspections

The following FAQs can help first-time trailer owners know what to expect during a DOT inspection. Each of these questions and answers has been sourced from the FMCSA, where detailed regulations and policies are outlined. 

What is the purpose of a DOT inspection of a trailer?

A DOT inspection ensures that vehicles and trailers are maintained in a safe operating condition. These safety regulations, determined by the Federal Motor Carrier Safety Administration, help to protect the motor carrier as well as the vehicle operator and other motorists on the road.

Does the DOT regulate how often maintenance and repairs must be performed on a commercial trailer?

While the DOT does require an annual inspection of commercial trailers over 10,000 pounds, it does not require a specific frequency of maintenance or repair. The motor carrier is responsible for determining how often their trailer needs servicing. Intervals between repairs and maintenance depend on the fleet and, in many cases, the individual vehicle.

For leased trailers, who has the responsibility of inspecting and maintaining the trailer?

The motor carrier is responsible for scheduling annual inspections of its leased trailers. They are also are responsible for appropriate repairs and maintenance as well as the storage of suitable records. Any defects determined during an inspection must be corrected by the motor carrier.

Where are inspection and maintenance records housed if a trailer is not maintained in a single location?

In cases where a trailer is housed and maintained in multiple locations, the motor carrier is allowed to retain their records at the location of their choice. However, the motor carrier is still responsible for ensuring that the records are up to date and factual. If the Federal Highway Administration (FHWA) requests the records, they must be made available within two working days no matter where the records are housed.

Who can inspect a trailer?

Commercial motor vehicles and trailers are to be inspected every 12 months by a qualified inspector. These inspectors must be trained and certified for the inspection and maintenance of commercial motor vehicles. 

What components of a commercial vehicle must be inspected?

Every single component of a commercial motor vehicle must be inspected:

  • The tractor
  • The semi-trailer
  • The full trailer (including converter dollies when applicable)

Do different states have different requirements?

Each state has its own requirements for vehicle inspections. Always check with your local DOT authorities to learn more about any state-specific regulations. 

Helpful Resources for DOT Trailer Inspection Requirements

If you're a first-time trailer owner, you might find it useful to explore the following resources:


Purchasing a commercial trailer is a big investment that requires careful research and planning. It is critical that first-time trailer owners understand the legal requirements of operating a commercial vehicle.

The process of passing a DOT trailer inspection will be less stressful and more efficient if you’re armed with the right knowledge. The end result goes beyond retaining the legal right to operate a commercial trailer — it ensures your safety and that of your fellow motorists.



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