MOT pass rates by make and model

Common questions

Which car model has the best MOT pass rate?

Of the 140 models with enough test data to compare fairly, the Audi A8 has the highest pass rate once age and mileage are accounted for, at 88.6%. The national average across all class 4 tests is 72.3%.

Why adjust pass rates for age and mileage?

An unadjusted pass rate mainly reflects how old the cars being tested are, not how well they were built. Rank models on raw rates and you produce a list of which cars were bought most recently. Each model here is measured within age and mileage bands, then reweighted onto the national distribution, so it is compared against cars that have lived a similar life.

Why do only some models get a ranking?

Of the 854 models here, 262 have enough spread of ages and mileages for an adjusted pass rate, and 140 of those are supported across at least 85% of the national range, which is the bar for appearing in the tables above. A car sold only in the last four years has no fifteen-year-old examples, and no arithmetic can say how it will look at fifteen. Every model still gets its failure and advisory patterns, which come from real tests either way.

Does a low pass rate mean a car is badly built?

Not on its own. An MOT records whether a car met a legal standard on the day, so the result reflects how a car has been used and maintained as well as how it was made. Consumable items such as tyres, bulbs and wiper blades cause a large share of failures and say more about upkeep than engineering.

Where does this data come from?

The DVSA anonymised MOT testing dataset, published under the Open Government Licence, covering 33,143,168 class 4 initial tests. Retests are excluded so each car is counted once, and abandoned tests are excluded entirely.