Do Trailers Under 3.5 Tonnes Need 6-Weekly PMI Inspections?
When it comes to trailer safety and compliance, one of the most common questions we hear from operators is:
“Do trailers under 3.5 tonnes need regular PMI inspections like HGVs and trailers over 3.5t?”
The short answer is: Yes – they should be subject to planned, regular inspections. While the Goods Vehicle Operator Licensing system and the DVSA Guide to Maintaining Roadworthiness (GtMR) formally apply to vehicles above 3.5t, the guidance makes it clear that the same principles apply to light trailers too.
From the Guide to Maintaining Roadworthiness (DVSA, 2023, p.1):
“The general principles could equally apply to light goods and passenger vehicles below the operator licensing threshold.”
Read the GOV.UK guidance here
Why Inspections Still Matter for <3.5t Trailers
Even though your Ifor Williams, Nugent, Bateson, Indespension, or similar plant/caravan/boat trailer may not appear on your Operator’s Licence, the DVSA expects it to be:
- Safe, roadworthy and fit for purpose
- Inspected and maintained on a planned schedule
- Supported with proper records of checks and repairs
If your trailer is involved in an incident, the Traffic Commissioner will want to see evidence of proactive maintenance – not “we fix it when it breaks”.
How Often Should Trailers Be Inspected?
The DVSA recommends a PMI interval of 4–13 weeks depending on usage and mileage. For trailers under 3.5t, it’s best practice to:
Align PMI inspections with your towing vehicle’s schedule (e.g. every 6 weeks for commercial operators).
Adjust intervals based on intensity of use:
- Heavy/frequent use: every 4–6 weeks
- Moderate use: every 8–10 weeks
- Occasional/low use: up to 13 weeks, with evidence of low mileage/usage
Remember, a trailer without records is treated as a non-maintained trailer in the eyes of DVSA.
Transport Managers: Your Responsibility
If you’re a Transport Manager under an O-Licence, your duty of care extends to all trailers in the fleet, regardless of weight. Ignoring light trailers could leave you exposed at Public Inquiry.
📍 Find qualified Transport Managers on the TM Map
or simply Google “TM Map”.
☎️ You can also call 07833 684449 to connect directly.
Training Your Team to Stay Compliant
At Towing Solutions, we help businesses and Transport Managers put robust trailer safety systems in place. Our Trailer Servicing & Maintenance Courses cover:
- PMI inspections for trailers of all sizes
- Legal compliance and DVSA expectations
- Practical checks: brakes, suspension, electrics, lights, couplings, tyres
- Record-keeping for Operator Licence and audit purposes
Whether you run a fleet of traffic management trailers, plant transporters, or light utility trailers, our training ensures your staff know how to keep them roadworthy and compliant.
Final Word
While DVSA guidance doesn’t impose a strict “6-weekly rule” on trailers under 3.5t, regular PMI inspections are expected and strongly advised. By applying the same standards as you would for heavier trailers, you:
Reduce risk of roadside prohibitions (PG9s)
Protect your O-Licence and Transport Manager reputation
Keep your drivers, operators, and the public safe