Trailer compliance: the half of the fleet that gets forgotten

Ask a transport office how many vehicles they run and you will usually get the number of motive units. Ask how many trailers and there is often a pause. That pause is the problem in miniature: a trailer is a separate asset with its own test date, its own inspection cycle and its own defect history, and in most fleets it is tracked considerably less carefully than the tractor unit pulling it.

The reason is structural rather than careless. A unit has a driver who sees it every morning, a fuel card, a tachograph and a service booking. A trailer has none of that. It gets dropped at a customer's yard on Tuesday, picked up by a different driver on Thursday, and may not return to the operating centre for weeks. Nobody owns it in the way somebody owns a unit, and the assets nobody owns are the ones that quietly go out of date.

A trailer is a vehicle for compliance purposes

It is worth being blunt about this, because the informal language of the yard works against it. Trailers are specified on the operator's licence, counted against the authorisation, subject to annual testing in their own right, and covered by the same maintenance undertakings as everything else on the licence. A roadside check can and does result in a prohibition issued against a trailer. The operator's OCRS score does not distinguish between a defect found on a unit and one found on the trailer behind it.

So when the licence authorises a number of vehicles and a number of trailers, both figures matter, and both can be exceeded. Operators who have grown by picking up a couple of second-hand trailers to cover a seasonal peak sometimes discover at the worst possible moment that they are running more than the licence permits — which is a variation application, not a paperwork tidy-up.

Why trailer inspections slip

Safety inspection intervals are set by the operator and declared to the Traffic Commissioner, and the frequency that is right for a unit is not automatically right for a trailer. A tipping trailer working off-road on a quarry contract, a curtainsider doing motorway trunking, and a step-frame that spends most of the year parked are three genuinely different maintenance propositions, and treating them as one is how a schedule stops reflecting reality.

The practical failure is rarely a decision to skip an inspection. It is that the trailer was not at the depot on the day the inspection was due, the planner moved it to next week, and next week it was somewhere else again. Three deferrals later the inspection is six weeks overdue and nobody has made a conscious choice at any point. This is exactly the pattern DVSA examiners are alert to during a maintenance investigation, because the records show it plainly: a neat schedule with a growing gap between planned and actual dates.

The paperwork that goes missing

A complete maintenance record for a trailer should be assemblable on demand: the inspection sheets in date order, the defects found, the rectification signed off by whoever did the work, and the brake test evidence. In practice the gaps tend to be in the same places. Work done by a third-party fitter while the trailer was away from base, with the paperwork left in a cab or emailed to somebody who has since left. Defects noted on a driver's walkaround that were rectified at the roadside and never written up. Brake performance assessed by a road test rather than a laden roller brake test, because the trailer was empty when it came in.

None of those are dramatic failures, and that is why they accumulate. The question an examiner asks is not whether the operator intended to keep good records but whether the records exist, and a trailer that has been maintained perfectly well by a competent fitter with no retained evidence is, for licence purposes, a trailer with no maintenance history.

Drivers, coupling and the checks that get rushed

The daily walkaround covers the combination, not just the unit, and the trailer-specific items — coupling security, landing legs, suspension, lights and reflectors, brake lines and susies, load security points, and the condition of the floor and body — are the ones most often skipped when a driver is coupling up in the dark at an unfamiliar yard. A driver picking up a trailer they have never seen before is also the person least able to say whether a defect is new.

That argues for making the trailer's own recent history visible at the point of coupling rather than filed at the depot. A driver who can see that this trailer had a brake line replaced last week, or that a tyre was flagged and not yet rectified, checks differently from one working with no context at all. It also closes a real gap in the record: when the driver who finds a defect is not the driver who reported the last one, the only thing joining them together is the trailer's file.

Hired and subcontracted trailers

Short-term hire is where responsibility feels blurred and generally is not. If a trailer is being operated under the licence, the operator's undertakings apply to it, and the hire company's own maintenance regime does not transfer that responsibility away. The sensible working assumption is that an operator needs to be able to evidence the condition of every trailer it pulls, including the one that arrived on Monday and goes back on Friday — which in practice means a first-use inspection and a record of it, not an assumption that the hire company has it covered.

The same logic applies in reverse to trailers lent to subcontractors. An operator whose trailer is damaged by a haulier it subcontracted to still owns the asset, still has it specified on a licence, and still has to account for its condition when it comes back.

Making the forgotten half visible

Most of the fix is not technical. It is deciding that the trailer fleet is a register in its own right, with the same fields the vehicle register has: next test, next inspection, current defects, where it physically is, and who last had it. Once that exists, the scheduling problem becomes tractable — a planner can see that three trailers are due inspection in the next fortnight and route them back to base rather than discovering it after the fact.

It also changes the conversation with the Traffic Commissioner if it ever comes to that. An operator who can produce a trailer register showing planned and actual inspection dates, with the deferrals explained, is in a materially different position from one who can produce a drawer of inspection sheets and an apology. The underlying maintenance may be identical. The evidence is not.

Inspection frequencies, testing requirements and the detail of what must be recorded are the kind of thing that changes, and operators should work from current DVSA and Traffic Commissioner guidance rather than from how the yard has always done it. What does not change is the principle underneath: a trailer is a vehicle on the licence, and the licence does not care that nobody drives it home at night.