Please note: we have since performed a bigger test of 7 million vehicles.
We decided to test 50,000 vehicles to get a better knowledge of how many have dodgy mileage, when we say “dodgy mileage” what we mean is:
- A vehicle that has had its mileage lowered between MOT tests, for example 01/05/2017 (80,000 miles) and then on 01/05/2018 (60,000 miles)
- A vehicle with a mixture of odometer readings, for example kilometres and miles.
The Overall Findings
We started this test on the 6th July 2019 and completed it on the 8th July 2019, here are the overall findings:
- Total vehicles tested: 50,000
- Total vehicles failed; 3964 out of 50,000
- Total fail percentage: 7.92%
Mileage Failures Broken Down
- Failed on lowered mileage: 3664 out of 50,000
- Failed of lowered mileage percentage: 7.32%
- Failed on mixed odometer readings (miles and kilometres): 510 out of 50,000
- Failed on mixed odometer readings percentage: 1.02%
- Failed on both mixed odometer readings / lowered mileage: 209 out of 50,000
- Percentage of above: 0.418%
As you can see from the above data, the biggest offender for mileage fails in our test was vehicles that had their mileage lowered between MOT tests, also known as the clocking of a vehicle.
Fail Rates by Make
Please note, some makes of vehicle had less than 1000 mileage checks in total, this means the overall figure may be less accurate than the makes with a higher number in the total checked data.
Explanation of data
- Make – The make of the vehicle.
- Total Checked – How many were checked out of the total 50,000.
- Total Failed – How many failed out of the Total Checked for this make.
- Fail Rate – The percentage that failed by make, worked out using the total checked and total failed data.
Fail Rates by Make & Model
Please note, some makes and models had a low amount of checks in total, this means the overall figure may be less accurate than the makes and models with higher total checks.
Explanation of data
- Make + Model – The make and model of the vehicle.
- Total Checked – How many were checked out of the 50,000 total checks.
- Total Failed – How many failed out of the Total Checked for this make + model.
- Fail Rate – The percentage that failed by make + model, worked out using the total checked and total failed data.
Worst by Year of Registration
We compiled the 3964 failed checks by year, we then worked out which year of registration came out the worst for mileage issues.
It turns out 2005, 2006 and 2004 came out the worst effected years in this test.
Explanation of data
- Year – The vehicles year of registration, for example 2005.
- Total Fails –Mileage fails out of the total 3964.
- % of Total Fails – The percentage that failed by year, worked out using the total fails data against the overall mileage data fails figure (3964).
Estimated vehicles with mileage issues in UK
In order to work this figure out, we must know how many vehicles are in the UK.
Estimated 38.2 million vehicles in the UK (racfoundation.org).
Our total fails percentage for this test was: 7.92%
7.92% of 38,200,000 =
This makes the estimated figure just over 3 million. This figure is higher than our initial test we carried out last month which came out at an estimated 2,471,539 vehicles and a 6.47% fail rate when we tested 12,300 vehicles.
More about this data
Below we have explained how this test was carried out, the data source of the test and where we got the test registration plates from. We think doing this helps readers get a better understanding of how it was done.
How did we perform this test?
We created a custom piece of software; this software did the checking and gave us the results, if anyone needs to do something similar (bulk data processing of vehicle registrations), we would be more than happy to discuss it.
Where was the data from?
we sourced this data from the gov.uk MOT API.
Where did we get the vehicle registrations?
We randomly picked the vehicle registrations from searches performed in our free check since the website was launched. We think there is no better source of vehicle registrations than this, solely because the searches are natural, from used car buyers and not from any previous research or publicly available websites or lists.
What’s the point of this data?
To help used car buyers better understand the risks – Anyone who is in the trade or thinking about buying a used car should do so with caution, we released our mileage checking tool for free to the public in June 2019 – you can give it a try here. But if you are serious about buying a used car you should perform a full vehicle history check as well. Because, mileage is only one piece of the puzzle when it comes to a vehicle’s history.
Want to know more?
If your interested in this data, we may be able to share a copy of it with you in certain circumstances. For example, if you wish to validate the figures or carry out your own research for a good enough reason – Please contact us at: email@example.com