Two tests, one on-road and one in the laboratory, will replace a single test that has not been updated for 20 years
Sam Sheehan
1 September 2017

Two real-world tests begin today to more accurately measure emissions of vehicles sold in Britain, replacing a single test that has not been updated for 20 years.

The tests, which measure fuel consumption, carbon dioxide, nitrogen dioxide, particulates and carbon monoxide, are part of European regulations intended to improve air quality and tackle climate change. They are being rolled out as part of Europe-wide reforms following the Volkswagen Dieselgate scandal.

From 1 September, every new car model will undergo a test called Worldwide Harmonised Light Vehicle Test Procedure (WLTP), which is conducted under laboratory conditions like the previous test. However, the new one is faster, longer and more dynamic, with a greater range of vehicle and engine speeds, engine load, gearchange and temperatures. 

The second test, called Real Driving Emissions (RDE), will see cars analysed on urban and rural roads as well as motorways for 90 minutes, with measuring equipment placed on their exhaust system. It is the first time anywhere in the world that cars will be tested on roads.

By 1 September 2018, all new cars on sale will have undergone WLTP testing, and by 1 September 2019, all will have undergone RDE testing too.

Regarding RDE tests, Government estimates suggest that they will help cut nitrogen oxide emissions from new diesel vehicles by two-thirds. The Government claims that this reduction will be possible because where some cars were shown to have performed better in the lab than in real life, now they will have to conform to emissions limits in public - something that will force manufacturers to produce even cleaner powertrains. A diesel-testing programme last year found that several Euro 6 diesel cars were emitting around six times more nitrogen dioxide in the real world than in the lab.

Certain models, such as those caught up in Dieselgate, were engineered to perform better in lab conditions, therefore deliberately skewing their CO2 and NOx outputs in order to be categorised as lower-emitting vehicles. Others saw rises in emissions after 20 minutes – the duration of the lab process. 

Transport Minister Paul Maynard said the new testing structure is part of broader ambitions to improve air quality in Britain. From 2020, councils will be given power to enforce tougher restrictions on the highest polluters of nitrogen oxide.

“We are taking strong action to clean up our air and these tough new emissions standards will reduce dangerous pollutants,” he said. “This will ensure all vehicles meet rigorous standards when driven on our roads – and we are going even further by tightening requirements again in 2020.”

Mike Hawes, CEO of the Society of Motor Manufacturers and Traders, said: “We welcome this challenging new regime, which will provide hard evidence that the industry's ongoing investment in ever more advanced technology is delivering on air quality goals. Combined, these new and demanding tests will soon give consumers emissions performance information that is far closer to what they experience behind the wheel – and inspire greater confidence that the new cars they buy are not only the cleanest but the most fuel-efficient ever produced.”  

Earlier this year, the UK Government revealed plans to ban the sale of pure combustion engine cars from 2040. Some critics, including Aston Martin CEO Andy Palmer, believe the legislation will have little impact, because the market is naturally heading in this direction.

More content:

WLTP and RDE fuel economy and emissions tests explained 

Volkswagen engineer sentenced to prison for dieselgate involvement

Comment: How the Government's air quality strategy could hit used car buyers

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29 August 2017

This is all very well if Manufacturers can actually build cars which can pass the test and still be drivable.

My guess is that the only way this will happen is with cars which have their drivability/performance severely hampered, maybe this will all hasten the demise of the buyers love affair with the 'fuel of the devil' - I do hope so!


29 August 2017

So, you want diesels to die even if they can be made much cleaner ? Like some sort of dictator you want to force you views onto everyone. What next, maybe you want people to only buy the cars that you like ?


29 August 2017

Typos, have you actually read what you wrote.....? Have a word with yourself please.

Explain where i am dictating to others exactly....I am merely voicing an opinion - thats what Forums are for!

Clearly your love of the van engine is clouding your judgement here, but at least you are living up to your name.

1 September 2017

I read what you wrote, you dont like diesels and you think eveyone should not like them even if they can be made much cleaner, its all there in plain English, its your hatred of diesels that is fueling your bias, clearly indicated by "van engine" "fuel of the devil", although actually, diesels can equally be described as "racing engines" - theyve won Lemans more times than I can remember. You "hope" that "the buyers love affair" with diesels ends. Surely, as long as they can be made much cleaner (and they CAN), its horses for courses, personal choice people can buy them if they want, you dont have to buy one, but if other people want to let them ? But no, youre hoping that they they dotn, hence my comments - because you dont like them you dont want anyone to have them. Its not hard to work out.

29 August 2017

Look at ADAC ecotests. Diesels BMW 118d, 520d and Mercedes E220d pass all Euro6 limits. Toyota hybrids do very well but the Hyundai/Kia hybrids have excessive CO and particles due to their direct injection engines. The Suzuki Ignis SHVS does well. Practical, affordable, reliable cars can be made which properly obey emissions laws in normal driving. 


29 August 2017

Interesting that there is no SMMT quote in this story. Presumably even they can't hold the line that all Euro 6 diesels are 'clean' for much longer.

29 August 2017
These new tests will bring an end to the car makers dodgy practices leading to unachievable MPG figures and noxious emissions. This should have been done a decade ago but for the collusion between the governments and the diesel lobby. Mind you even these new tests allow the diesel to emit emissions twice as much as allowed on paper!

29 August 2017

Yes it should ahve happened years ago, but there was no "collusion" as you put it, diesels were encouraged for the right reasons (lower CO2) but at the same time as this encouragement, emissions regs for them should also ahve been made tougher, this would ahve meant that power outputs woulnt have climbed so quickly, but we all could ahve lived with that. As for your comment about "new tests allow (ing) the diesel to emit emissions twice as much as allowed on paper", well that doesnt make any sense - you need to specify WHICH pollutants youre talking about, they emit less of some and more of others, something most band wagon jumping, headline informed, factually ignorant people posting on here seem to be totally unaware of.

29 August 2017

Yes, this test should have happened years ago but all governments didn't have the guts to upset the car industry. Real world MPG tests also need to be available.


29 August 2017

It was the governments that told the car industry to go in the diesel direction !!!!


One thing that has NOT been addressed is the UK MOT, in which, for petrols an advanced sensor is put into the exhaust that measures about 5 pollutants (all of which are clear and invisible) and will fail a car if any are too high, whereas for diesel a much simpler sensor is put into the exhaust that ONLY measures smoke, it doesnt measure any chemical pollutants at all. Smoke (particulates) is the only one of many different chemicals that petrols and diesels emit that is not clear, all others are clear and invisible (CO, NOx CO2, SO2 etc), so why the hell has the MOT not been revised to also test diesels for other pollutanats too, for gods sake ? Just another example of the diesel engine getting the blame for poor legislation.


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