Nearly a million lorries, PSVs and trailers take the annual test each year, and about 89% pass first time. That headline sounds healthy until you flip it: more than one in ten vehicles arrives at the test station carrying a failure - and DVSA’s own analysis says most of those failures could and should have been picked up as part of the daily walkaround check before the vehicle was ever presented.
DVSA’s published top-ten breakdown is dominated by two areas. Lamps are the top failure reason at 3.5% of failures, followed immediately by headlamp aim at 3.4%. Brakes come next and weigh heavier in total: just over 6% of failures are brake-related, spread across brake system components at 2.9%, service brake performance at 2.2% and parking brake performance at 1%. Half of the top ten failure items sit in just those two areas - lighting and brakes. The remainder include tyres at 0.8%, plus steering and suspension defects.
DVSA’s own commentary is blunt about what this means. It is concerning, they say, how similar the top annual test failure reasons are to those of cars - because lorries, PSVs and trailers are subject to a far more rigorous maintenance and testing regime than private cars, and the same simple faults should not be surviving to test day.
A failed lamp is the most preventable failure there is. Checking whether a lamp works is as simple as switching the lights on and having a look - it takes a minute, it needs no equipment, and it is already part of the walkaround check every driver is supposed to do every day. Headlamp aim is only slightly harder: an obviously misaligned lamp shows up when you check the lights for operation and security, especially against a wall or shutter door.
The fact that lamps and aim still top the HGV failure charts is therefore not a technical problem. It is a daily-check problem: checks skipped, done from the cab, or done by a driver who reported the fault and was sent out anyway. Every one of those failures was visible - literally - for days before the test.
Brake failures split into two kinds. Component failures - the 2.9% - are often visible problems: worn pads, damaged lines, air leaks, slack adjusters out of range. A visual inspection picks up many of them, and anyone driving the vehicle should be able to recognise the more serious problems with the brakes through pedal feel and behaviour. Performance failures - service brake at 2.2% and parking brake at 1% - need a roller brake test to measure, which is why the Guide to Maintaining Roadworthiness expects brake performance assessment, ideally laden roller testing, at every safety inspection rather than once a year at the MOT.
The pattern to avoid is the fleet that meets its brake performance data for the first time at the annual test. A roller test at each PMI turns the MOT brake station into a formality; skipping it turns the MOT into a measurement you did not want.
Tyres must be checked daily as part of the walkaround check - tread, condition, inflation, wheel fixings - and at 0.8% of failures they are a smaller category but an inexcusable one, because a tyre that would fail the test was illegal on the road for weeks beforehand. Steering defects affect control of the vehicle and should be picked up when it is being driven: free play, heaviness, pulling. Suspension defects are often visible on a look-under: cracked leaves, leaking air bags, damaged dampers.
The actionable version of DVSA’s data is a pre-test checklist weighted to the failure table: full lights-on walkaround with someone at the controls, headlamp aim checked against a fixed reference, brake performance measured within the current inspection cycle, a tyre and wheel check that is actually done daily rather than claimed daily, and a drive-and-listen assessment of steering and suspension. Do that and the annual test becomes what it should be for a maintained fleet - an external audit of a system that already works, not the day you find out how your vehicles really are.
The retest fee is the smallest line in a failure’s true cost. Add the rebooking delay, the vehicle standing while parts arrive, the reshuffled work, and the entry in the testing data that follows the operator’s record - first-time pass rate is one of the numbers DVSA’s risk scoring takes seriously. A fleet that fails on a lamp has paid all of that for a bulb and a one-minute check. That arithmetic is why the failure tables matter beyond the test station: every item on DVSA’s top-ten list is a place where a cheap daily habit prevents an expensive annual event, and the fleets with the best first-time pass rates are simply the ones whose daily habits actually happen.