What is a periodic maintenance inspection (PMI) and how often is it required?

A periodic maintenance inspection — the PMI — is one of the core obligations that comes with holding a Goods Vehicle Operator's Licence. Understanding what a PMI involves, how frequently your vehicles must be inspected, and what records you must keep is essential for any operator who wants to maintain a sound compliance position.

What is a periodic maintenance inspection?

A periodic maintenance inspection is a scheduled, systematic safety inspection of a goods vehicle or trailer carried out by a competent person — typically a qualified vehicle technician or an approved workshop. Unlike a driver's daily walkaround check, which is a visual pre-use inspection carried out by the driver each time the vehicle is used, a PMI is a more thorough examination of the vehicle's mechanical and safety systems.

DVSA's Guide to Maintaining Roadworthiness describes the PMI as the foundation of a preventive maintenance system. Its purpose is to identify and rectify developing mechanical faults before they reach the point where they cause a defect on the road, a prohibition at the roadside, or a vehicle failure.

The PMI is separate from the annual MOT test. The MOT is a statutory roadworthiness test administered by DVSA-authorised testing stations once per year. A PMI is an operator-organised inspection carried out at regular intervals throughout the year — typically every six to thirteen weeks depending on the vehicle type and operation. Both are required; the PMI does not replace the MOT, and the MOT does not replace the PMI.

How often must an HGV be inspected?

DVSA does not specify a single mandatory interval for all vehicles. Instead, operators are required to set a maintenance inspection interval that is appropriate for the type, age, and use of each vehicle in their fleet. The interval must be documented in the operator's maintenance programme and agreed with the maintenance contractor if external workshops are used.

The Guide to Maintaining Roadworthiness sets out indicative intervals:

• Every six weeks — typical for heavily used HGVs, older vehicles, or vehicles operating in arduous conditions (construction, waste, agriculture). Six weeks is also the interval DVSA uses as a default in compliance assessments for most HGV operators.
• Up to thirteen weeks — for newer, lightly used vehicles in less demanding operations. Operators choosing a longer interval must be able to justify it with evidence of vehicle condition and operational history.
• More frequently — high-mileage or specialist operations may require shorter intervals. Tippers, tankers, and refrigerated vehicles, for instance, often operate on shorter maintenance cycles than general haulage.

The Traffic Commissioners have consistently emphasised that the maintenance interval is not a formality — it is an undertaking. Operators who set an interval and then allow vehicles to run past it are in breach of their O-licence maintenance undertakings, even if no defect is found when the overdue inspection eventually takes place.

What an O-licence operator must do

When an operator applies for a Goods Vehicle Operator's Licence, they sign undertakings that include a commitment to ensure vehicles are inspected at regular intervals. These undertakings are not aspirational — they are legally binding conditions of the licence. The Traffic Commissioner can and does take action against operators who fail to maintain their inspection programmes.

In practical terms, your O-licence maintenance undertaking for PMIs means:

• Setting a written maintenance inspection interval for each vehicle (or vehicle type) in your fleet
• Arranging inspections to take place at or within that interval
• Using a competent person or approved workshop to carry out each inspection
• Retaining a written record of every PMI — what was inspected, what was found, and any work carried out
• Acting promptly on any defects found during a PMI, including grounding the vehicle if necessary
• Recording the next due date and ensuring the vehicle returns for its next inspection on time

Operators should also ensure that their maintenance contractor is aware of their O-licence obligations. A workshop that simply carries out work without issuing a formal inspection record — or that issues inspection records without covering all the required items — is not supporting the operator's compliance position, even if the physical work is being done correctly.

What a PMI must cover

DVSA's guidance sets out the items that a periodic maintenance inspection should cover. The exact scope will depend on the vehicle type, but typically includes:

• Braking systems — brake lining condition, drum and disc condition, brake adjustment, air leaks
• Steering — play, condition of track rod ends and ball joints, power steering operation
• Tyres — condition, tread depth, inflation, any damage or irregular wear
• Wheels and wheel fixings — including wheel nut condition and security
• Suspension — springs, air bags, shock absorbers, condition of suspension components
• Lighting — headlights, brake lights, indicators, marker lights, fog lights
• Mirrors and glazing
• Fuel, oil, and coolant systems — for leaks, levels, and condition
• Exhaust system — including emissions equipment
• Body and chassis — structural condition, load-securing points, access steps
• Coupling equipment — where applicable, for articulated vehicles and trailers

The PMI should also include a brake test — typically a roller brake test — to verify that the braking system is performing within legal limits. DVSA considers brake performance a high-risk defect category; vehicles that have not been brake-tested at their PMI are considered to have an incomplete inspection record.

What records must be kept

Every PMI must be documented. DVSA requires operators to retain PMI records for a minimum of 15 months. This covers the typical audit window used by DVSA compliance examiners and Traffic Commissioners — usually the previous 12 to 15 months of maintenance history. Our article on how long vehicle inspection records must be kept covers the retention requirements across all record types.

A complete PMI record should include:

• The vehicle registration number and fleet number
• The date and mileage at the time of inspection
• The name and qualifications of the inspector or workshop
• A record of each item inspected and its condition
• Any defects found — including minor items for monitoring
• Work carried out during or as a result of the inspection
• Brake test results
• Inspector sign-off — a named declaration that the vehicle was inspected and the findings recorded
• The next due date for the following inspection

Records without brake test results, unsigned inspection forms, or records that simply state "vehicle checked — no faults" without substantiating detail are regularly identified by Traffic Commissioners as inadequate. The record must demonstrate that the inspection actually took place, not merely that it was scheduled.

Common mistakes operators make

Traffic Commissioner public inquiry decisions regularly reference the same types of PMI-related compliance failure. The most common include:

• Vehicles running past their PMI date — an interval is set but not enforced in practice. Vehicles are used in service after their due date without the inspection having taken place.
• Missing brake test results — the inspection is carried out but the brake test is omitted, incomplete, or not recorded.
• Inspection records that don't cover all items — forms that are partially completed, or workshop certificates that are too generic to show what was actually checked.
• Defects found at PMI not acted upon — the inspector notes a defect but the vehicle continues in service without the defect being rectified.
• Records lost or retained for too short a period — paper records that cannot be produced for the previous 15 months leave the operator unable to demonstrate a consistent inspection history.

How HauliK supports PMI record keeping

HauliK's maintenance and PMI module, available from the Fleet plan, lets operators record each periodic maintenance inspection with the inspector's name, outcome, sign-off timestamp, and next due date. Overdue alerts are shown when a vehicle's next PMI date has passed — giving transport managers immediate visibility of any vehicle that has fallen behind its maintenance schedule.

Records are stored and accessible from the web dashboard alongside walkaround check records, defect reports, and repair sign-offs — giving operators a single location for the maintenance history that DVSA examiners and Traffic Commissioners expect to see.

HauliK stores maintenance and PMI records from the Fleet plan. PMI scheduling — the automatic generation of recurring inspection intervals — is planned for a future release. Current PMI records include scheduled date, outcome, inspector name, sign-off, and next due date entered by the operator.

For operators still managing PMI records on paper or across disconnected workshop job cards, a digital approach to O-licence compliance can make the 15-month retention requirement significantly easier to meet in practice.

Frequently asked questions

Can I carry out PMIs myself?

An operator can carry out PMIs using their own workshop staff, provided the staff are suitably qualified and equipped. The DVSA Guide to Maintaining Roadworthiness sets out the competency requirements. Many operators use an approved external workshop or dealership. The key requirement is that the inspector is competent — not simply that they are employed by the operator or by a third party.

What happens if a vehicle fails its PMI?

A vehicle that fails its PMI should not return to service until the defects have been rectified and a competent person has certified it roadworthy. The failure and subsequent repair must both be documented. Continuing to operate a vehicle that has failed its PMI is a serious compliance breach and can result in a prohibition notice if the vehicle is encountered at the roadside.

Does a PMI replace the annual MOT?

No. The MOT is a separate statutory test that must be passed annually. PMIs are in addition to the MOT and are carried out more frequently throughout the year. An up-to-date MOT certificate is required alongside a current PMI record — one does not substitute for the other.

What if my PMI falls at the same time as the annual MOT?

Many operators align their PMI with the annual MOT test where possible. This is acceptable — the MOT inspection is detailed and comprehensive — but the PMI record must still be completed and retained separately, and the remaining PMIs throughout the year must still take place at the agreed interval. The MOT only accounts for one inspection per year; most vehicles will require several PMIs in between.