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Stricter MOT test doubles emissions failure rate

May changes introduced more stringent emissions testing.

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Changes to MOT emissions testing has seen the number of cars failing more than double since being introduced earlier this year.

In May 2018, emissions testing within the overall MOT test became more stringent — with smoke of any colour coming from the exhaust resulting in an automatic failure. Automatic failure also applies to any car showing evidence of a diesel particulate filter (DPF) that’s been tampered with.

Six months on, and new Driver & Vehicle Standards Agency (DVSA) figures show 744,592 cars have failed the MOT emissions test — a sharp rise from 350,472 for the same 20th May to 19th November period in 2017.

Diesel cars failing in droves

Of those failed cars, 505,721 were petrol powered — up from 292,468 — while diesel saw a meteoric rise from 58,004 to 238,971 failures.

Meanwhile, the rise in vans failing emissions testing increased from 3,585 in the same time frame to 19,468 — a 448% increase.

Commenting on the figures Gareth Llewellyn, DVSA chief executive, said that the agency’s priority is to protect everyone from unsafe vehicles and drivers. “We are committed to making a real difference to those in society whose lives and health are blighted by poor air quality,” he added.

“Since introducing the new tighter MOT emissions test in May, nearly 750,000 vehicles have been taken off the road or fixed,” Llewellyn said.

Overall MOT failure rates remain steady

Despite the large increase in cars failing on grounds of emissions, the failure rate for the MOT test remains steady since the changes were introduced.

34.7% of petrol cars failed between May 20 and November 19, 2018, a slight drop from 35.7% for the same period in 2017, while diesels saw a marginal decrease from 33.8% to 33.2%.

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Andrew Charman
Andrew Charman
Andrew is a road test editor for The Car Expert. He is a member of the Guild of Motoring Writers, and has been testing and writing about new cars for more than 20 years. Today he is well known to senior personnel at the major car manufacturers and attends many new model launches each year.