Diesel sales dip ‘likely to accelerate’ by 2020

A decline in the market share of new diesel cars sold in the UK is likely to speed up by the end of the decade, research has suggested, but an emissions expert has questioned how this could impact efforts to tackle air quality.

The comments follow the release of the latest car registration figures published last week, suggesting that demand for new diesel cars fell by as much as 17% in 2017 (see story).

Latest figures have suggested that sales of new diesel cars fell by 17% in 2017

Speaking today (9 January) Professor David Bailey, a leading industrial academic at Aston University, suggested that diesel car makers face a “raft of challenges”, and that sales of new diesels are likely to decline further in 2018.

Last week’s figures, published by the motor industry, stated that overall car sales had fallen for the first time in six years, while the market share of new diesel car sales had dropped from 47% in 2016 to 37.8%, while petrol cars made up 56% of the new models registered in 2017, compared to 49% in 2016.


Commenting on the outlook for diesel, Professor Bailey, said: “Diesel cars face a raft of challenges, each one of which could damage sales, and which are combining to kill off the domestic diesel sector, which was so rattled by the ‘Dieselgate’ scandal.

“They face a ‘perfect storm’ of bad PR over pollution, coupled with concerns over increasingly strict regulations and sinking second-hand values.

“Sales of diesels are set to fall by up to 10% in 2018, and they could have as little as 30% of the market by 2020 — shrinking rapidly to 15% by 2025. And this is despite diesels accounting for 50% or more of the market just a few years ago.”

Professor Bailey called for measures from government including a scrappage scheme to continue to incentivise drivers to move away from diesel cars.

Diesel cars are known to emit lower levels of CO2 than petrol vehicles, and have benefited from favourable levels of vehicle excise duty to boost sales in order to help meet greenhouse gas reduction targets since the early 2000s.

However, many diesel cars also emit higher levels of air pollutants such as nitrogen oxides, which can worsen air quality and harm human health — and have faced a backlash in recent years due to failure to meet air quality objectives in the UK.

Air Quality

Anti-diesel campaigners will most likely welcome the slowdown in sales as positive news for efforts to improve the UK’s air quality — with diesel cars, particularly older models, acknowledged as a major contributor to air pollution in towns and cities. But, others view the trend in a different light.

“If people are hanging on to a Euro 3 diesel, rather than buying a Euro 6 that is going to slow down improvements in air quality.” — Nick Molden, chief executive, Emissions Analytics

Nick Molden, chief executive of the vehicle testing firm Emissions Analystics — has expressed concern that a slowdown in the sale of new diesel cars in the short term, could have a negative impact on efforts to tackle air pollution in towns and cities.

Speaking to, Mr Molden said that the 2017 registration figures do not suggest that consumers are opting for petrol cars over diesel models in significant numbers, with only a 2% increase in petrol car registrations recorded in 2017, despite the 17% drop in diesel.

He said: “In simple sense it looks like buyers have gone on strike. It is not like the same number of vehicles are being sold and people are just buying petrol. It looks like people don’t know what to do. They don’t know whether vehicles might be banned from city centres. If people are hanging on to a Euro 3 diesel, rather than buying a Euro 6 that is going to slow down improvements in air quality.”

Mr Molden — whose company runs the independent vehicle emissions testing directory, the EQUA Index — added that the figures point to a longer-term shift away from diesel cars, but said that this would not necessarily be positive news in efforts to tackle air pollution, if it meant that consumers are avoiding buying newer, less polluting cars.


“Longer term it reflects a cycle away from diesel,” Mr Molden said. “If all diesels were dirty that would be a good thing, but we know that is not the case. There are 21 diesels with EQUA ‘A’ ratings that exist. If you look at the NOx of the top 10% of diesels they are better performing than a lot of petrol cars. And, they still retain their CO2 advantage.”

Through the EQUA Index, Emissions Analytics has tested the air quality performance of over 600 new petrol and diesel car models available for sale in the UK — offering an ‘A’ to ‘H’ grade depending on the findings of the real-world testing cycle.

Data published on the EQUA Index suggests there is a huge disparity between the emissions performance of new diesel cars. (Click to expand) Source: Emissions Analytics

Data available on the EQUA Index websites suggests that some older diesel cars emit lower levels of NOx than new models placed onto the market, while some of the best performing new diesel models are comparable to petrol cars on air pollution emissions.

Mr Molden added that this creates complexity for policy makers seeking to restrict the most-polluting vehicles from operating in parts of towns and cities where air quality challenges exist, particularly if they are using emissions standards which may not reflect the actual level of emissions of vehicles on the road.

Related Links
Aston University
EQUA Index


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