PMI inspection interval guide

A preventive maintenance inspection (PMI), called a safety inspection in the DVSA's roadworthiness guide, needs an interval suited to the vehicle or trailer and how it is used. The operator sets and notifies its maintenance interval, then must keep inspections within it and review whether the interval is controlling defects in practice. There is no single universal six-week rule for every HGV. DVSA's Guide to Maintaining Roadworthiness gives a normally used range of 4–13 weeks with different examples for operating conditions, while indicating that vehicles and trailers aged 12 years or older should be inspected at least as frequently as every six weeks. A shorter interval may still be necessary.

This guide is for goods-vehicle operators in Great Britain and their transport managers. Check the operator's own licence undertakings, notified interval, maintenance contract and current DVSA guidance before changing a schedule. Passenger vehicles have related roadworthiness guidance but may have different licensing and operating arrangements. The Northern Ireland regime has its own licensing administration, so do not copy a GB operator process into it without checking local requirements.

What the interval means

The interval is the planned gap between formal safety inspections, not the gap between driver walkaround checks, servicing, annual tests or repairs. Those activities complement one another but are not interchangeable. A daily check may find a tyre defect today; a safety inspection examines the vehicle systematically at the scheduled point; a service follows the manufacturer's maintenance programme; an annual test is a separate statutory test. Passing an MOT does not erase a missed safety inspection or a defect found after the test.

The goods vehicle operator licensing guide says safety inspections, including brake tests, and other statutory testing should take place within the operator's notified maintenance intervals. It also expects a maintenance planner with preventive inspection dates at least six months ahead, and maintenance records retained for at least 15 months. Those records must be available to traffic commissioners when requested. The operator remains responsible even if a contractor performs inspections.

A decision process for setting the initial PMI interval

1. Identify each vehicle and trailer. Record type, age, manufacturer guidance, axle and body equipment, registration or trailer identifier, typical load, routes, terrain and annual mileage. Do not give a whole mixed fleet one interval merely to simplify a spreadsheet.
2. Describe actual duty. Trunking on easy routes is different from stop-start urban work, construction sites, quarry access, heavy loads or corrosive environments. Include seasonal peaks and trailers that are swapped between vehicles.
3. Review defect and inspection history. Look at driver reports, prohibitions, failed annual tests, recurring defects, brake performance and the amount of unscheduled repair. A low-defect history needs evidence; an unexplained absence of defect reports is not proof of good condition.
4. Select a starting interval from DVSA's guide. Its examples are 10–13 weeks for lightly loaded easy conditions, 6–10 weeks for general-haulage trunking, 4–6 weeks for arduous constant heavy loads, and four weeks for off-road difficult conditions. For vehicles and trailers aged 12 or more years, its indicated six-week ceiling may need shortening further on the evidence. These are guidance examples, not a blanket entitlement to run every vehicle at the longest end.
5. Check the licence and maintenance arrangement. Confirm the notified interval, garage capacity, contract, inspector competence, brake-test arrangement and ability to remove unsafe vehicles from service. Notify or seek advice on a change through the proper operator-licensing process before treating a revised interval as operative.
6. Build the forward planner. Schedule each vehicle and trailer in ISO weeks or a consistent controlled system, at least six months ahead, including annual tests and known calibration/testing dates. Assign the inspection provider, booking owner and escalation if a slot is missed.
7. Review effectiveness. Inspect defect trends and outcomes regularly. If defects emerge between inspections or the duty becomes harsher, increase frequency or add intermediate checks. Record why an interval remains suitable or why it changed.

The DVSA guide says inspection frequency should reflect likely mechanical deterioration, considering age, manufacturer recommendations, load, equipment, operation, terrain, distance, speed and journey times. An experienced operator can tailor intervals by vehicle group when evidence supports it. The guide also notes that new operators lack their own maintenance history, so they need an initially defensible schedule and close review.

Practical examples

Example 1: newer trunking vehicles. A fleet of relatively new HGVs mostly runs predictable trunk routes with moderate loads and reliable inspection access. The manager uses DVSA's general-haulage 6–10 week example as a starting envelope, then chooses a specific interval based on manufacturer advice, mileage, defect history and brake evidence. The chosen interval is entered in the licence arrangements and planned by vehicle. The team reviews whether wheel-end, tyre, brake or other defects recur before the next planned inspection. If they do, the longer interval is no longer justified merely because it lies in the example range.

Example 2: site tippers. Vehicles frequently travel on construction sites, carry heavy loads and encounter mud, impacts and more wear. DVSA's arduous/off-road examples point to shorter intervals, potentially around four weeks depending on conditions. The manager records the usage assessment and arranges intermediate attention for high-wear items where needed. The transport office does not push an inspection back because a vehicle has a profitable job; operational needs must not override safety.

Example 3: older trailer. A trailer is 13 years old and sometimes sits idle. DVSA's guide indicates no more than six weeks between safety inspections for vehicles or trailers aged 12 or more while in use, and says vehicles returning from a period out of service should be inspected before being used again. The operator reviews the trailer's condition and operating intensity; a four-week plan may be more appropriate if defects and duty warrant it. An idle period is not a substitute for a pre-use inspection.

These examples are planning illustrations, not preauthorised schedules. An inspector or transport manager should decide the actual interval using the fleet's evidence and the current guide.

How to schedule inspections without stretching an interval

DVSA recommends using ISO weeks, which run Monday to Sunday, so an inspection can be planned for a defined week. In the DVSA guide's six-week example, an inspection in week 10 leads to planned weeks 16, 22, 28 and so on. Suppose the vehicle is inspected early in week 20 because it was in the workshop. The operator should either still inspect it in week 22 to retain the original plan, or restart six-week intervals from week 20 to weeks 26, 32 and so on. Simply waiting until week 28 would turn the next gap into eight weeks, outside the six-week plan. The guide explicitly uses this example.

Record the actual completion date and ISO week, not just a coloured due-date box. If the booking fails, the manager must decide whether the vehicle can be used; a missed interval should not be hidden by backdating or changing the planner. Hold it until inspection and roadworthiness decisions are made in the correct process. If the vehicle receives an unscheduled safety inspection following a breakdown, decide and document whether the original schedule is retained or reset.

Useful planner fields: vehicle/trailer ID; current interval; basis for interval; previous inspection date/week; next planned ISO week; provider and booked date; brake-test plan; annual test and other statutory dates; result and roadworthiness declaration; defects and repairs; actual inspection record link; interval review date; and the manager who approved any change. Keep trailers visible even when no tractor unit is permanently assigned.

Brake tests, records and provider oversight

Do not treat “PMI completed” as a sufficient record if the inspection and brake evidence are missing. DVSA's guide addresses brake performance within safety inspections and gives detailed options and conditions for laden roller brake tests, other methods and electronic monitoring. The right arrangement depends on the vehicle, test capability and the current guidance. This page deliberately does not reduce that guidance to a universal brake-test frequency. The operator should have a specific brake-test plan, check each inspection's evidence and investigate weak results.

The safety inspection report should identify the vehicle, inspector, date, odometer where applicable, items inspected, defects, rectification and roadworthiness decision. DVSA says records of safety inspection and repair work must be retained for at least 15 months, whether the work is in-house or contracted. A vehicle should not return to service until it is declared roadworthy. Where a contractor performs the work, the operator still needs prompt access to the completed record and must challenge poor or incomplete reports.

A good review looks across evidence, not only a calendar. Compare inspection findings with driver defect reports, roadside stops, annual-test outcomes, repairs, component replacements and vehicle age. If the same fault family repeatedly appears between inspections, the interval or preventive controls may be inadequate. Equally, a stable record could support a review of the interval, but any extension needs a documented basis and the appropriate licence notification process. Avoid a “copy last year's interval” exercise.

Common interval mistakes

• Calling six weeks a universal legal rule. DVSA gives a risk-based range and specific older-vehicle guidance. Licence undertakings still matter.
• Using the longest example interval without considering duty. A general-haulage table row does not justify a 10-week interval for a tipper working off-road.
• Planning by mileage alone without managing time. Duty may change and defects can develop while mileage is low; choose a controlled approach consistent with DVSA guidance and the licence.
• Counting service or MOT as an automatic PMI. Only a completed safety inspection with the required scope and report fulfils the planned inspection task.
• Stretching the next date after an early inspection. Recalculate the schedule so the declared interval is not exceeded.
• Omitting trailers. They need their own maintenance and inspection evidence, even when exchanged across vehicles.
• Keeping the planner but losing the report. An entry saying “done” does not show defects, rectification or roadworthiness.
• Assuming the garage owns compliance. Contractors can perform inspections; the licensed operator remains accountable for the maintenance system.
• Failing to react to a new operation. A vehicle moved onto a construction-site contract may need more frequent inspection before historic defect data catches up.

Product connection and next step

For broader vehicle compliance context, see Complys' fleet compliance page. The more relevant commercial route here is HGV and operator compliance, which describes planned PMI scheduling and maintenance records. That product is labelled as launching, not currently live. This article must not instruct readers to start an available Complys PMI workflow or promise current reminders, inspections, brake analysis or automatic compliance decisions. The appropriate CTA is to review the planned service or register interest while managing today's duties through the operator's existing arrangements.

Next step: Check your notified inspection intervals against vehicle age, actual use, defect and brake history; build the next six months' planner; verify provider capacity; and document the review. Recheck the current DVSA roadworthiness guide and your licence position before implementing or publishing a changed interval.

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