2020 sees record number of MOT failures – and there’s one common denominator

2020 sees record number of MOT failures – and there’s one common denominator

Nearly 1.3 million vehicles failed their MOT in the UK last year for one particular reason, it's the most times it's ever happened.

According to the figures, faults relating to exhaust emissions have risen by over 70% in just two years.

Diesel vehicles are performing worst, with a whopping 240% rise in emissions-related failures since new regulations were introduced in May 2018. The increase for petrol vehicles is just 37%.

Why did the regulations change in 2018?

Clearly something serious changed in 2018 to cause such a sharp increase in emissions-related faults. As you might expect, the changes followed the VW emissions cheating scandal and form part of the Government’s clamp down on emissions in the run-up to the (now) 2030 ban on new petrol and diesel cars.

The 2018-onwards rules apply to cars, vans, motorcycles and other light passenger vehicles. Among other changes, like new vehicle categorisations and new items for testing, stricter rules for diesel car emissions were introduced.

Any vehicle with a diesel particulate filter (DPF) now receives a major fault (and immediate failure) if the MOT tester finds smoke of any colour exiting the exhaust. Evidence of tampering to the DPF also results in immediate failure.

The changes were a direct response to a surprising number of drivers employing specialist firms to remove DPFs. Apparently it most commonly happened when filters became clogged by soot and other pollutants. But, ironically, removal of the DPF only served to further reduce the performance of the vehicle!

Rise in petrol failures equally significant

The fact that the changes to testing criteria only apply to diesel vehicles explains the enormous jump in diesel failures. But that 37% increase in emissions-related failures for petrol vehicles represents something just as significant.

You see, petrol vehicles didn’t escape the changes to MOT rules completely. Any that emit blue or oily smoke for more than 5 seconds while idle can be failed now too.

And while a 240% rise in emissions-related failures for diesels might seem far greater than the 37% increase for petrol vehicles, a closer look reveals that the latter are the worst performers.

In reality, petrol cars are more likely to fail on emissions with 4.5% of the total number of licensed unleaded vehicles doing so. Meanwhile, it’s only 3.3% of the total number of registered diesel vehicles that are failing on emissions faults.

Another reason to switch to electric?

Jessica Potts, head of marketing at BookMyGarage.com, who requested the testing information from the DVSA, explained why these rising numbers might make drivers think twice about their next purchase.

“What this data tells us is that an increasing number of relatively modern diesels are struggling to pass the MOT test as their emissions control systems face tougher scrutiny. It’s important these systems function correctly to protect the environment but putting them right can also cost owners thousands of pounds.”

Has your fleet experienced problems with MOTs since the new regulations came in three years ago? Tell us about your experience! Drop a comment below or send an email to info@drivingmonitor.com.