Gasoline hybrids show the fewest technical defects, while cars remain relatively trouble-free until their tenth birthday. Beyond that, problems rise sharply, especially with increasing mileage. These are some of the most remarkable findings of Flanders’ first GOCA Barometer, based on more than two million vehicle inspections.

Flanders’ first comprehensive car inspection barometer reveals some surprising differences in the technical condition of passenger cars. Petrol hybrids outperform fully electric, petrol, and diesel vehicles, while age and mileage increasingly take their toll beyond ten years and 150,000 kilometers.

Presented on Friday, 6 November, by GOCA Vlaanderen, the federation of Flemish vehicle inspection operators, the study covers 2,072,410 unique passenger cars inspected between 1 July 2025 and 30 June 2026 at 43 recognized inspection centers.

Overall, 360,981 vehicles (17.4%) had defects that required a follow-up inspection or resulted in a driving prohibition. Of those, 29,980 cars (1.4% of all vehicles) received an immediate driving ban.

No judgement

According to GOCA spokesperson Dirk Snauwaert, the initiative aims to make the wealth of information collected daily by inspection centers accessible to journalists, policymakers, and consumers.

“We do not pass judgment. We inform,” he stresses. Inspired by Germany’s TÜV Report, which has existed for more than 50 years, GOCA wants to contribute objective data to discussions about road safety, environmental protection, and consumer confidence. To avoid rankings based on very small samples, individual models are included only after at least 500 inspections, or 150 for electric vehicles.

But the barometer also raises questions that deserve closer scrutiny. Why are headlights by far the most frequently recorded defect, even among relatively young cars?

And why do certain electric models perform considerably worse than others, even when they share the same technology? We examine both questions in the next two parts of this series.

Ten years seems to be a turning point

The figures reveal remarkably little deterioration during the first decade. Among four- to five-year-old cars, 10% had recorded defects, compared with 10.1% for six- to seven-year-old cars and 11.5% for eight- to nine-year-old cars.

Beyond ten years, the curve becomes noticeably steeper: 14% from ten to eleven years, approximately 18% from twelve to thirteen years, and 23% from fourteen to fifteen years. Among vehicles nearly eighteen years old or older, one in three (33.7%) had defects.

Mileage shows an even stronger correlation. Only 7.6% of vehicles with 25,000–50,000 kilometers had defects, compared with 15.3% at 100,000–125,000 kilometers, 23% at 150,000–175,000 kilometers, and a striking 42.2% beyond 300,000 kilometers.

However, GOCA emphasizes that correlation does not establish causation. Older cars generally have higher mileages, and the figures do not establish which factor contributes most to deterioration.

Hybrids outperform fully electric cars

Despite combining combustion and electric propulsion, petrol hybrids consistently register the lowest defect rates across the age categories studied.

Among four- to five-year-old vehicles, 8.9% of gasoline hybrids had defects, compared with 9.2% of conventional petrol cars, 10.8% of fully electric vehicles, and 12.4% of diesels. At six to seven years, the difference widens: 8.3% for petrol hybrids, 9.1% for petrol, 12.6% for electric cars, and 13.1% for diesels.

However, these figures do not prove that hybrid technology is inherently more reliable. GOCA does not adjust its results for mileage, vehicle model, maintenance, or usage patterns.

Moreover, the barometer groups vehicles into petrol and diesel hybrids without separately identifying conventional hybrids (HEVs), plug-in hybrids (PHEVs), or range-extender EVs (EREVs). Their individual performance therefore remains unknown, making direct conclusions about the reliability of different electrified powertrains premature.

Nevertheless, the findings challenge the widespread assumption that EVs inevitably develop fewer technical problems simply because their drivetrains contain fewer moving parts.

Diesel’s surprising comeback

Diesel cars perform worse than petrol cars when compared at the same age. But the picture reverses when comparing vehicles with similar mileages.

At 100,000–125,000 kilometers, 16.3% of petrol cars had defects, compared with 14.3% of diesels. Beyond 300,000 kilometers, the difference becomes even more striking: 52.1% versus 41.1%, respectively.

Diesels generally cover considerably greater distances. Four- to five-year-old diesels averaged 91,600 kilometers, compared with 57,500 kilometers for petrol cars. This does not necessarily make diesel technology more durable. Differences in vehicle age, driving patterns, and maintenance remain important factors.

Headlights top the defect list

Perhaps the most unexpected finding concerns the nature of the defects. Headlights are by far the most frequently recorded category, affecting 108,879 vehicles, or 5.3% of inspected cars with a known model.

But how serious are these problems? A slightly misaligned headlight is hardly comparable to defective brakes or dangerously worn suspension, although incorrect beam adjustment can also pose a safety risk.

The GOCA Barometer does not distinguish minor adjustment errors from more serious headlight defects, raising questions about how much the overall rejection figures really tell us about vehicle safety.

The issue is particularly controversial because motorists sometimes report passing a second inspection without having made any repairs — a phenomenon GOCA itself has acknowledged. We investigate this further in part two of our series.

The barometer clearly measures technical inspection outcomes, not the proportion of vehicles posing an immediate road-safety risk.

A timely contribution to the inspection debate

The publication comes as Flanders fundamentally relaxes its mandatory vehicle inspections. Since 1 September 2026, passenger cars can generally qualify for a two-year inspection certificate regardless of age or mileage.

From 1 January 2027, mandatory pre-sale inspections for used vehicles already registered in Belgium will also be abolished, while imported vehicles will remain subject to inspection.

The reforms have sparked debate about road safety and consumer protection. GOCA’s figures provide new evidence of how technical defects increase with age and mileage, raising questions about whether older cars should be inspected less frequently.

However, the study does not establish how many accidents inspections prevent, and not every recorded defect constitutes an immediate danger.

As the first edition of an annual barometer, it provides a baseline rather than evidence of a long-term trend. Future editions may help assess whether the condition of Flanders’ vehicle fleet changes under the relaxed inspection regime.

For now, the central finding is that age, mileage, and propulsion technology each tell a different story — and that understanding the nature of a defect is just as important as counting how many cars have one.

More to come

In part two of our GOCA Barometer series, Newmobility.news digs into the data to reveal which car models perform best and worst in Flemish technical inspections, comparing vehicles of similar ages. From Volvo and Toyota to Tesla and Skoda, we uncover some surprising results and see how they stack up against findings elsewhere in Europe.

Part three takes a critical look at the most frequently recorded defect and a notorious source of irritation among motorists: headlights. Why are so many cars flagged for lighting problems, and how can some pass a second inspection without any repairs? We investigate what these results really tell us about road safety.