HGV Safety Inspection Intervals: Choosing and Reviewing the Right Frequency

“We inspect every six weeks” sounds controlled, but it does not answer whether six weeks is suitable for a particular vehicle. DVSA guidance normally places safety-inspection frequencies between four and 13 weeks and expects operators to tailor and monitor the interval.

The defensible answer is not a habit. It is a documented decision supported by operating conditions and results.

Declared frequency and actual suitability

The inspection frequency stated when applying for an operator’s licence is a commitment. The actual system must deliver inspections at or before that interval, while also responding sooner when condition or use demands it.

An interval that was appropriate for new trunking tractors can become too long after vehicles age, move to construction work or develop repeat defects. Conversely, an experienced operator with strong evidence may use different intervals across a mixed fleet rather than applying one number mechanically.

DVSA’s 4–13 week guide

The current Guide to Maintaining Roadworthiness gives these examples:

These examples guide a decision; they do not mean every trunking vehicle automatically qualifies for ten weeks. Vehicle design, mileage, defects, environment and maintenance performance still matter.

Risk factors that shorten an interval

Consider:

• age, mileage and known component life;
• heavy, dusty, corrosive or off-road work;
• high annual distance or intensive multi-shift use;
• repeated driver defects or PMI findings;
• brakes, tyres, steering or suspension trends;
• annual-test failures and roadside prohibitions;
• new or unproven vehicle types;
• weak workshop performance or incomplete records;
• long periods parked followed by sudden use;
• trailers exchanged between operations with limited history.

Use intermediate checks for known high-wear items where appropriate, but do not label a narrow tyre or brake check as a full safety inspection.

Older vehicles and trailers

DVSA guidance indicates a minimum six-week frequency for vehicles and trailers aged 12 years or older. Age is calculated at asset level, so a new tractor does not make a 14-year-old trailer “newer” as a combination.

Older assets may need still shorter intervals if defects or use justify it. The six-week figure is not a promise that every older asset will remain roadworthy for six weeks.

Monitor whether the interval works

An interval is effective when vehicles remain roadworthy between inspections and defects are found early enough to control risk. Review:

• safety-inspection defects per asset and severity;
• driver-reported defects between inspections;
• repeat repairs and deferred work;
• breakdowns related to safety systems;
• brake-performance trends;
• annual-test initial pass rate;
• roadside findings and prohibitions;
• late or missed inspections;
• workshop record quality.

A low PMI defect count can mean excellent maintenance, but it can also mean superficial inspections. Sample the records and compare them with driver reports, repairs and independent results.

Planned date, actual date and schedule reset

Forward planning should show at least the next inspection dates, usually much further. If an inspection is brought forward, decide whether the future cycle runs from the actual inspection or returns to the original pattern. The answer should avoid creating a gap longer than the committed interval.

For example, a six-week inspection completed one week early could either reset the next due date to six weeks from the actual inspection or retain the earlier planned date. What is unsafe is treating the early visit as permission for seven weeks until the next one without a justified system.

Record planned date, actual date, odometer, next due date and who approved any interval change.

Worked fleet examples

Trunking tractor

A three-year-old tractor on predictable motorway trunking has strong defect and test history. An eight-week interval may fit DVSA’s general-haulage range, with driver checks and trend review supporting it.

Quarry tipper

A tipper works off road with heavy loads, high brake and suspension wear and frequent damage exposure. Four weeks may be suitable, with intermediate high-wear checks. A generic six-week company policy would need challenge.

Older spare trailer

A 13-year-old trailer is used infrequently. Low mileage alone does not remove deterioration, seizure and tyre-age risk. The guide indicates six weeks for its age, and first-use checks are important after idle periods.

These are illustrations, not prescriptions. The operator’s own evidence decides.

Documenting an interval change

Record the asset group, old and new interval, risk factors, performance data, decision maker, effective date and review date. Update the forward planner and, where the declared maintenance arrangements or licence undertakings require it, notify the Office of the Traffic Commissioner.

Shortening an interval after defects is straightforward risk control. Extending it needs stronger positive evidence and ongoing monitoring. Do not extend merely because the workshop is busy.

Common mistakes

• Treating six weeks as law for every HGV.
• Grouping tractors and trailers without considering separate ages and use.
• Extending frequency after one clean inspection.
• Counting late inspections from the planned rather than actual control point.
• Ignoring intermediate driver defects when reviewing effectiveness.
• Changing the planner without retaining the decision.
• Allowing workshop availability to set the risk threshold.

Digital maintenance planners can prevent missed dates and expose defect trends, but the operator must make and review the interval decision.

Frequently asked questions

What is the legal HGV PMI interval? There is no single universal interval. DVSA guidance normally ranges from four to 13 weeks, with the operator choosing a suitable frequency and meeting declared arrangements.

Must vehicles over 12 years be inspected every six weeks? Current DVSA guidance indicates a minimum six-week frequency for vehicles and trailers aged 12 years or older.

Can different vehicles have different intervals? Yes. Experienced operators may tailor systems to different vehicle and operating characteristics if the decisions are controlled and effective.

Can an early inspection extend the next due date? Only within a planned system that never creates an unjustified gap. Record how the schedule is reset.

When should frequency be reviewed? Regularly, and after material changes, repeat defects, failures, prohibitions, new work or ageing into a different risk group.