How often should an HGV safety inspection be done?

There is no single safety inspection interval that DVSA requires of every vehicle. DVSA asks you to judge how quickly your vehicles deteriorate doing the work they actually do, set a frequency that matches, declare it on the vehicle operator licensing service (VOL), and then meet it. The interval is yours to choose and yours to account for. ("PMI", preventative maintenance inspection, is industry shorthand for what DVSA calls a safety inspection; the two mean the same thing here.)

The figure almost everyone repeats is six weeks. It is not a legal requirement, a legal maximum, or "the DVSA interval" - it is one frequency among several in a guidance table running from 4 to 13 weeks. There is exactly one place where a specific figure attaches to a specific class of vehicle, vehicles and trailers aged 12 years and older, and even there the guide permits the frequency to be extended. Both sentences of that passage are below.

What is legally binding is the interval you declared. Section 1.5 of the guide puts it as a "must": operators must ensure safety inspections are carried out at the stated frequency as recorded on VOL. So the risk in adopting six weeks because everyone else has is not that six weeks is wrong - for a lot of fleets it is a sensible answer. It is that you have declared a figure you cannot account for, and you are held to it either way.

Where the six-week figure comes from

Six weeks recurs throughout DVSA's guidance table, appearing in three of its five rows: the tight end of "General haulage - trunking" (6-10 weeks), the loose end of "Arduous work - constant heavy loads" (4-6 weeks), and the single figure given for vehicles and trailers 12 years or older. For a mixed haulage fleet you arrive at it from more than one direction, which is much of why it gets repeated as though it were the standard.

It is not the standard, and repeating it without having done the assessment behind it is the real exposure. It cuts both ways. Six weeks may be too long - the table gives 4 weeks for off-road and difficult conditions - or shorter than your operation needs, in which case you are buying inspections you could have justified not buying. Either way, the guide is where any assessment of your arrangements starts:

"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 underlying legal duty is not a number at all: 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".

What DVSA actually requires

Section 4.2 of DVSA's Guide to maintaining roadworthiness sets out the test:

"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."

Those six factors are the assessment. Nothing in the passage names a number, because the number is the output of working through them for your vehicles and your operation.

The guide is explicit about its own language, and it pays to know which tier you are reading. Where it says you must, that is "a direct legal requirement set out in legislation, something that is required under Road Traffic law, Health and Safety legislation, or the legal undertakings to the Traffic Commissioner for your operator licence". Where it says you should, that is best practice, "strongly recommended that you do unless you can demonstrate that an alternative approach provides a similar level of compliance". The interval-setting sentences above are written in "should" - inspections "should, where practical, be programmed to follow a time-based pattern", and the frequency "should be determined by assessing" the likely deterioration. The duty to meet the interval you go on to declare is written in "must".

Experienced operators get explicit latitude:

"If you are an experienced operator, you are free to tailor these inspections to suit the nature of your operations and vehicle characteristics."

The same paragraph allows more than one system across a fleet, where vehicles and the nature of their work vary, and ends: "Systems will be judged primarily on their effectiveness in maintaining roadworthiness."

The guidance table

DVSA publishes a table of typical frequencies by operating condition, introduced like this:

"An inspection frequency would normally range between 4 to 13 weeks. See table below for examples of operating conditions. Operators may also consider intermediate safety checks for high-wear items. This may allow the frequency of the safety inspections to be extended, see section 4.5 – ad hoc safety inspection intervals."

| 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 |

Read that as worked examples, not bands you have to fit into. DVSA offers it as examples of operating conditions, to help you land on a frequency after working through the six factors - not as a rule, a standard, or a legal schedule.

The 13 weeks at the top is the top of the guidance range, and the longest equivalent time frequency the guide says should be entered on VOL. It is not a statutory maximum, and it does not stop a Traffic Commissioner requiring something shorter.

If your problem is a few fast-wearing components rather than the whole vehicle, follow up that reference to intermediate safety checks: checking those items between full inspections can support a longer full-inspection interval. See the intermediate safety check explained.

Vehicles and trailers 12 years or older

This is the one place where a specific figure attaches to a specific class of vehicle, and the passage any argument about six weeks has to deal with. Section 4.2, under the sub-heading "Older vehicles and trailers":

"National statistics show that as vehicles and trailers age, the average annual MOT failure rate increases, and they are more likely to experience in-service roadworthiness defects than newer vehicles. Therefore, the guidance has reflected that older vehicles and trailers will need more frequent maintenance and has indicated a minimum safety inspection frequency of 6 weeks requirement for vehicles and trailers aged 12 years and older."

"However, depending on usage, such as low mileage and light conditions, the frequency may be extended."

Take the two sentences together, because DVSA wrote them together. The first is the closest the guide comes to fixing a figure for a class of vehicle; the second makes it conditional on how the vehicle is actually used. Note the wording as well - "the guidance has reflected", "has indicated". That is neither of the two tiers section 1.1 defines: DVSA does not say "must" here, and it does not say "should" either. The permission to extend comes from the second sentence itself, not from any classification of the first.

So the working position for an older vehicle is that six weeks is the frequency to start from, and the one you would need to account for if you go longer. Extending it is expressly permitted, but on the grounds DVSA itself names: low mileage, light conditions. Those grounds are what you would be relying on, so they need to be recorded somewhere they can be produced - you are going longer than the figure the guidance points to for the vehicle's age, and the guide is the Traffic Commissioner's starting point for whether your arrangements are satisfactory.

Your declared interval is binding

This is the part that matters day to day, and it is worth being exact about where the force comes from. What makes your declared interval binding is section 1.5, which uses "must":

"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 then sets the operational rule. The passage below is itself "should" language - the force comes from section 1.5 above, not from these words:

"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."

Three things follow.

The declared figure, not the table, is what you are measured against. The 4-to-13-week table is guidance; the number on VOL is a licence undertaking. The table being guidance gives you no room at all to miss the interval you declared.

You cannot extend by decision alone. Deciding ten weeks suits a vehicle better than eight is legitimate; running it at ten while VOL still says eight is not. Update the record first.

The phrase "and not beyond" makes the interval a deadline, not a target. An inspection due in one week that happens the next has gone beyond the specified time scale, whatever the reason for it.

Running early has consequences too, because the schedule itself has to stay intact. The guide works an example on a 6-weekly interval planned by ISO week: a first use inspection in week 10, with inspections then due within weeks 16, 22, 28, 34 and so on. If one falls outside that plan - after a breakdown, say - a new schedule may need to be created. In DVSA's own example it "would not be permissible to carry out an early SI in week 20 and then have an 8-week interval to week 28". You either inspect again at week 22 and keep the original schedule, or reschedule 6-week intervals from week 20 to 26, 32 and so on. That example is also where the cycle starts: before a newly acquired vehicle goes on the public highway, operators must conduct a first use inspection, unless there is sufficient evidence it has already had a safety inspection.

Mileage-based programmes are allowed, but they do not escape the time framing - DVSA says a mileage-based programme "will need to be linked to time". VOL records a time-based frequency for both vehicles and trailers, so where a mileage-based frequency is adopted the guide says the expected maximum equivalent time frequency should be entered on the system, up to 13 weeks, and to ensure the mixed frequency box is ticked. The same process covers a mixed time frequency across a fleet. Note the modality: entering that figure is a "should". The hard "must" is section 1.5's duty to update VOL whenever your arrangements for safety inspections change.

Frequently asked questions

Is a six-week PMI interval a legal requirement?

No. DVSA sets no single fixed interval for all vehicles; six weeks is one frequency in a guidance table running from 4 to 13 weeks. For vehicles and trailers aged 12 years and older the guidance indicates six weeks, but immediately allows that frequency to be extended depending on usage, such as low mileage and light conditions. What binds you legally is the interval you declared on the vehicle operator licensing service (VOL).

What is the maximum HGV safety inspection interval?

DVSA's guidance range tops out at 13 weeks, which is also the longest equivalent time frequency the guide says should be entered on VOL. It is the top of a guidance range, not a statutory maximum, and Traffic Commissioners reserve the right to require more stringent arrangements, such as shorter periods between inspections.

Can I change my safety inspection interval?

Yes, the interval is yours to set. But any changes to arrangements for safety inspections must be updated on VOL, and DVSA says the frequency should not be extended without updating VOL. Update the record first, then run to the new interval.

What happens if a safety inspection is carried out late?

DVSA says the following safety inspection should be carried out within the specified weekly or mileage-based time scale, and not beyond, and section 1.5 makes it a must that inspections happen at the stated frequency recorded on VOL. A missed date is a departure from an obligation phrased as a must, and Traffic Commissioners reserve the right to require shorter periods between inspections.

Can different vehicles on the same operator licence have different intervals?

Yes. DVSA says experienced operators are free to tailor inspections to their operations and vehicle characteristics, and may deploy more than one system across a fleet. Where a varied frequency is used the guide says to ensure the mixed frequency box is ticked on VOL. Systems will be judged primarily on their effectiveness in maintaining roadworthiness.