Setting and justifying your inspection interval

DVSA does not pick your safety inspection interval. It asks you to assess how quickly your vehicles deteriorate doing the work they actually do, choose a frequency that matches, declare it on the vehicle operator licensing service (VOL), and then meet it. The choosing is yours. So is the account of why you chose it.

"Everyone uses six weeks" is not that account. Whether six weeks is required at all - including the one passage where a figure attaches to a class of vehicle - is settled on how often an HGV safety inspection should be done. This page is the other half: how you get to a figure, and what you keep so it stands up without you standing next to it.

The duty you are meeting is not a number. For goods operators the guide cites section 13C (4) of the Goods Vehicles (Licensing of Operators) Act 1995, which requires that "there must be satisfactory facilities and arrangements for maintaining the vehicles used under the licence in a fit and serviceable condition". Your interval is one part of those arrangements, and DVSA's Guide to maintaining roadworthiness is where any assessment of them begins:

"Traffic Commissioners rely on this Guide as the starting point for whether or not arrangements are 'satisfactory' and 'suitable'."

Where they are not, Traffic Commissioners "reserve the right to require more stringent arrangements from you (such as shorter periods between inspections)".

The factors DVSA expects you to weigh

Section 4.2 states how the frequency should be determined:

"Operational needs must not override safety considerations. Safety inspections should, where practical, be programmed to follow a time-based pattern. The frequency at which inspections are undertaken should be determined by assessing the level of mechanical deterioration likely to be incurred over a period as a result of the vehicle's usage. This will depend on such factors as:

the age and type of vehicle operated

the recommendations of the vehicle manufacturer

the nature of its load, the equipment and fittings it carries or supports

the type and range of operations on which it is likely to be engaged

the type of terrain and the nature of the environment in which it operates or is likely to operate

the distance and speeds at which it travels and the journey times."

Two things in that passage bind differently. Letting operational convenience decide the interval is ruled out in the guide's "must" wording - "Operational needs must not override safety considerations". The method itself is a "should": the frequency "should be determined by assessing the level of mechanical deterioration likely to be incurred over a period as a result of the vehicle's usage".

No number appears there, because the number is the output of working the factors against your own vehicles. A note of that working is what makes the figure defensible. Taken one at a time:

"the age and type of vehicle operated" - Age is where a specific figure attaches to a class of vehicle, at 12 years and older, covered on the page linked above. Type is what the vehicle is, before you reach what it does; a mixed fleet giving several answers here is one route into more than one interval.

"the recommendations of the vehicle manufacturer" - The only external written standard on the list, and the cheapest to evidence - you can cite the document. If your interval is longer than the manufacturer's servicing interval, that is a visible difference and worth a line on the file.

"the nature of its load, the equipment and fittings it carries or supports" - The wording covers what the vehicle "supports" as well as what it "carries": tail lifts, cranes, tipping gear, tanks and the mountings under them, not just the payload. A vehicle that changes what it carries has changed one of the six inputs.

"the type and range of operations on which it is likely to be engaged" - The phrase "likely to be engaged" is forward-looking. Winning or losing a contract changes the answer before any wear has happened, so a change of work is a better trigger to revisit the assessment than the next review date.

"the type of terrain and the nature of the environment in which it operates or is likely to operate" - The table's own examples lean on this; "Off road - difficult conditions" is a whole row of it. Sites, salt and unmade roads sit here, and so does the season: a vehicle that spends winter on gritted roads is not doing the same job all year.

"the distance and speeds at which it travels and the journey times" - Three things are named, not one. Two vehicles on the same annual mileage are not the same case if one does it in long motorway runs and the other in multi-drop. This is also what pushes some operators towards a mileage-based programme.

The same six reappear in section 5.3, where a brake-test risk assessment "should consider the following": those headings in the same order, plus previous brake performance results, previous brake system and component condition, and acceptable reasons for not carrying out a laden brake assessment. If you have written one, most of this ground is already on paper - see braking performance assessment.

Where the guidance table fits

The table arrives with this introduction:

"An inspection frequency would normally range between 4 to 13 weeks. See table below for examples of operating conditions."

| Operating conditions | Frequency | |---|---| | A. Lightly loaded vehicles - easy operating conditions | 10-13 weeks | | B. General haulage - trunking | 6-10 weeks | | C. Arduous work - constant heavy loads | 4-6 weeks | | D. Off road - difficult conditions | 4 weeks | | E. Vehicle/trailer 12 years or older | 6 weeks |

Those are examples of operating conditions - not a rule, a standard or a legal schedule. Landing inside a band is not by itself a justification; the assessment is what connects your vehicles to a row. Four of the five rows are keyed to how the vehicle is worked. Row E is keyed to the vehicle itself: "Vehicle/trailer 12 years or older". If that is your row, take it together with the sentence that immediately qualifies it by permitting the frequency to be extended depending on usage - both are on how often an HGV safety inspection should be done.

The 13 weeks at the top is the ceiling the VOL system records, not a statutory maximum.

You are not confined to one interval across the fleet. An experienced operator is "free to tailor these inspections to suit the nature of your operations and vehicle characteristics", and may "deploy more than one system across a fleet, where vehicles and the nature of their work vary". What such a system is measured on is stated plainly: "Systems will be judged primarily on their effectiveness in maintaining roadworthiness."

Writing it into your maintenance programme

The interval stops being a decision and becomes a licence undertaking at the point it goes on VOL. Section 1.5 states two obligations, both as musts:

"Operators must ensure that safety inspections are carried out at the stated frequency as it is recorded on the vehicle operator licensing service (VOL)."

"Any changes by licensed operators to arrangements for safety inspections must be updated on the vehicle operator licensing service (VOL)."

Section 4.2 adds the operational rule, in "should" wording that those two musts stand behind:

"Whichever safety inspection (SI) interval is decided upon, the inspection frequency should not be extended without updating the vehicle operator licensing service. The following safety inspection should be carried out within the specified weekly or mileage-based time scale, and not beyond."

The phrase "and not beyond" makes your declared interval a deadline rather than a target: an inspection due one week and carried out the next has gone beyond the specified time scale.

The dates need to exist well ahead of the work. Section 1.5 asks you to identify inspection dates "at least 6 months in advance", using a maintenance scheduling system, planner or wall chart, and notes that electronic systems can be dynamic.

The cycle starts at the vehicle. Before a newly acquired vehicle goes on the public highway, "operators must conduct a first use inspection to satisfy themselves that the equipment is in a roadworthy condition" - unless there is sufficient evidence it has already had a safety inspection, such as a comprehensive pre-delivery inspection or a pre-rental inspection record from a hire company. That inspection is where the counting begins: in the guide's worked example a first use inspection in ISO week 10 on a 6-weekly interval puts the following inspections within weeks 16, 22, 28, 34 and so on.

ISO weeks are worth copying, because the section 4.4 list of what a report should show at least includes the date and ISO week of inspection. Planner and record then speak the same units.

Changing an interval

Changing the interval is allowed - the assessment is supposed to follow the operation, and operations change. Changing it quietly is not. Section 4.2 says the frequency "should not be extended without updating the vehicle operator licensing service", and section 1.5 makes any change to your arrangements for safety inspections a must to update on VOL. Update the record first, then run to the new figure.

An early inspection does not buy you a longer gap afterwards:

"If a safety inspection was completed outside the planned schedule, for example because of a breakdown, a new schedule may need to be created. For the example given above it would not be permissible to carry out an early SI in week 20 and then have an 8-week interval to week 28. The operator would need to either carry out another SI at week 22 – and continue with the originally planned schedule – or reschedule 6-week intervals from week 20 to 26, 32 and so on."

So an off-schedule inspection leaves two choices: inspect again on the original date and keep the schedule, or rebase the cycle from the new date. What you cannot do is let the following gap stretch to absorb the difference. On an ISO week planner that creep shows up immediately.

Mileage-based programmes

Mileage-based programmes are permitted, with a condition: they "will need to be linked to time". VOL holds a time figure, so the link is not decoration:

"The vehicle operator licensing service (VOL) records a time-based frequency for both vehicles and trailers. Therefore, if a mileage-based frequency is adopted, the expected maximum equivalent time-frequency should be entered into the system (up to 13 weeks). Then ensure the mixed frequency box is ticked on VOL to record that a varied inspection frequency is being used. This same process should be used if a mixed time frequency is being used for different vehicles or trailers on the fleet."

What is compulsory there is narrower than it looks. Entering the expected maximum equivalent time frequency is a "should" - best practice under the guide's own convention, not a legal requirement - while ticking the mixed frequency box is put as a direct instruction. The obligation that does bite is section 1.5's must to update VOL whenever your arrangements for safety inspections change.

Either way the figure you are held to is a time figure: section 1.5 attaches to "the stated frequency as it is recorded" on VOL, and what VOL records is time-based. The guide says the same process should be used for a mixed time frequency across a fleet, not only where mileage is involved:

"An update on the vehicle operator licensing service (VOL) will be required due to the change in the inspection frequency. The maximum frequency will need to be recorded on VOL. In this case, 6 weeks and the mixed frequency box ticked."

Where high-wear components are the constraint

If what is pushing you towards a short interval is two or three fast-wearing components rather than the whole vehicle, intermediate safety checks on those components are one documented route to a longer full-inspection interval. DVSA's wording for that route is permissive rather than automatic, and an extension still has to be recorded on VOL. The intermediate safety check explained sets out section 4.2's wording, what the route requires and DVSA's worked case study in full.

What good evidence looks like

Your assessment, your schedule and your records are three different things, and the records are what is left once the work is done. Retention is a must, at 15 months:

"Safety inspection and repair work records, whether undertaken by operators or contracted out, must be kept for at least 15 months as part of a vehicle's maintenance history."

That is longer than any interval in the guidance table, so a file kept to it holds several cycles rather than one inspection. That is what lets dated records show an interval rather than an event - the difference between asserting that you inspect every eight weeks and showing it.

Defects have to be traceable through to their fix, not merely listed. Where the data is captured electronically, "The records must show a clear audit trail from inspection to sign-off after repair (if one is needed)", and the guide calls it "very important" that the record includes "a declaration that the vehicle is fit for service or whether repairs are required".

Section 4.6 lists important features of a computerised system. Most are features rather than requirements - a compliance dashboard, collaborative digital planners, back-up and disaster recovery. Three are put as musts:

it must be tamper proof (for example, records cannot be changed at a later date)

it must be clear what's been checked and by whom

there must be a clear end-to-end audit trail

Treat those three as hard. The data also has to stay reachable - "Easy access to the data - for management and enforcement purposes - must also be available." - and one further requirement is organisational rather than technical:

"The operator must have a plan in place to ensure the system can be accessed by sufficient delegated people to maintain effective management control in the event of staff absence."

A system only one person can get into does not meet that, whatever its audit trail. Nor does any of this transfer the duty: DVSA tells software and hardware providers they "should make sure that any system they design considers the requirements of this guide", but "It is ultimately the operator's responsibility to make sure that any computerised maintenance system used meets the requirements of the operator licence."

None of it is an argument for software as such. The guide permits manual systems throughout, and "Computer records must contain the same information as any comparable manual form." Going electronic moves the bar rather than lowering it - you then have to meet "the minimum required standards of a manual system and the additional features specific to an electronic system". Either way a file that accounts for your interval looks the same: the reasoning behind the figure, a schedule planned far enough ahead to be met, dated inspections in sequence at the declared frequency, defects traced through to sign-off, and 15 months of it still there when someone asks.