The 66 plate — September 2016 to February 2017

16 against 66 — the same year, six months apart

Cars first registered in the two halves of 2016. This comparison exists only because the figures are cut by plate code rather than by year, which is not how MOT statistics are usually presented: a 66 car and a 16 car are the same model year, but the 66 was first registered up to six months later and has had six months less road under it. (The dataset records first registration, not the date a car was built.)

The 66 cars pass 1.6 points more often than the 16 cars. Median mileage is the same to within one 2,500-mile band, which is the finest distinction this data can draw — on mileage the two halves of the year are indistinguishable. Mileage is a 2,500-mile band midpoint.

Worth remembering when a seller calls a car “a 2016 car”: the two halves of that year are six months and one plate change apart, and the test record treats them as separate populations. Whether that gap is worth anything in money is a question for the used-car market, not for the MOT data — what the data can tell you is on the two rows above.

What mileage is normal for this period

Recorded odometer readings at test in 2025, banded to 2,500 miles, from 1,271,216 readings. The box is the middle half of cars; the line inside it is the median; the whiskers reach the 10th and 90th percentiles.

Half of the cars from this period tested in 2025 had between 46,250 and 86,250 miles on them — a spread of about 40,000 miles between cars of the same age. Below roughly 45,000 puts a car in the lowest-mileage quarter for its age; above roughly 85,000 puts it in the highest quarter, though mileage alone is not a condition judgement — the test record does not show how a car was serviced. The median works out at about 6.8k miles a year since registration. These are 2,500-mile band midpoints, so treat each as give or take a thousand or so.

The same cars, three years running

Cars first registered in the 66 plate period, tested in 2023, 2024 and 2025. Because the cohort is fixed, this shows two things at once: how these cars are ageing, and how fast they are leaving the road.

The number tested fell 1.8% between 2023 and 2025. Nearly all of that is cars from this period leaving the road — scrapped, exported or on a SORN — though a small part is cars still on the road whose test date drifted past a year end. Pass rates fell 3.5 points over the same three years, as the cars still being tested got older.

What they fail on

The failure mix for cars first registered in the 66 plate period alone, not the national average.

Share of this cohort's failure items, 2025 — the 8 biggest categories shown (97.3% of the items); smaller categories are not listed.

What the tester warns about

Advisories are what the tester flags as worth watching — not yet a failure, but on the way. They are the best guide to what cars from this period will need next.

Share of this cohort's advisory items, 2025 — the 8 biggest categories shown (98.3% of the items); smaller categories are not listed.

Dangerous defects

6.7% of cars from this period tested in 2025 were found to have at least one dangerous defect — 0.6 points below the 7.3% rate across all cars. A dangerous defect is DVSA's statutory category for a fault posing an immediate risk to road safety: driving the vehicle before it is repaired is an offence, whatever the MOT certificate says.

What they run on

The fuel mix of cars first registered in the 66 plate period, as recorded at test in 2025, and how each fuel's pass rate compares. Diesel accounts for 49.4% of them. The dashed reference line is the 76.1% average for the whole period, so a column above it is a fuel holding up better than the cars around it.

The most-tested makes from this period

The ten makes with the most first tests in 2025 among cars first registered in the 66 plate period, and how each one's pass rate compares with the 76.1% average for cars of this period. Measuring them against all cars of every age would only show that these cars are old; measuring them against their own contemporaries shows which ones passed most often.

By number of first tests in 2025 among cars of this period. Each links to that make's own MOT statistics, across every age.

First-time pass rates by model, 66 plate period

Highest and lowest 2025 first-time pass rates among grouped car models with at least 5,000 first tests within this cohort — 74 models qualify at that floor. All trims and variants are grouped under one model name; only models sold purely as cars are ranked, so vans, pickups and conversions in the same class-4 MOT are left out. Models sharing a published rate share a rank. A model absent from both lists had too few tests among cars from this period to rank at all.

A pass rate describes a fleet, not any one car. It reflects how these cars were driven, maintained and used as much as how they were built, and beyond recorded mileage none of that is in the data. A well-kept example of a model low on this list can pass; a neglected example of one high on it can fail.

What the letters either side mean

The two letters before the 66 say where the car was first registered — usually the supplying dealer's region. They do not say where the car is now, and they are not the postcode areas on our MOT statistics pages, which record where a car was tested. The three letters after the space mean nothing at all. The full table of both is on the number plate guide.