Volkswagen's scandal has called the issue of how cars obtain their emissions figures in Europe into question
Matt Prior
16 October 2015

There are lots of things wrong with the NEDC, the process via which cars sold in Europe have their emissions and fuel consumption calculated.

The chief grumbles are that the New European Driving Cycle isn’t new, bears no resemblance to European conditions and features no driving. Other than that, it’s spot on.

The NEDC, last revised in 1997, is usually conducted in a laboratory on a rolling road, where it’s most repeatable. Manufacturers can switch off ancillaries and set the ambient temperature, and the whole shebang lasts only 11 (stationary) kilometres – some urban driving and some higher-speed driving, after which you get a combined total.

A manufacturer can conduct the test itself, as many times as it likes before the car goes on sale, until it has a result it’s happy to publish; and although an engineer has to use the pedals to match speeds and acceleration points, it is, according to my colleague Mark Tisshaw, “like playing a really hard game of Space Invaders with your feet”, rather than driving.

The number that comes out of the end is the one that manufacturers quote, and that we quote in our first drives until we’ve had the chance to obtain a more realistic number ourselves.

At the moment, the NEDC has been pulled into the mire alongside Volkswagen, although it shouldn’t really be. Any sensible manufacturer will do its homework to perform as well as it can in what amounts to the NEDC’s classroom examination. VW arrived at said exam having slipped a cheat sheet into its back pocket. As BMW’s R&D boss, Klaus Fröhlich, said last week: “A defeat device is a no-go. That brings you in jail.”

The NEDC’s actual issues, then, are simply that they’re not representative of what you’d see in the ‘real world’. What you get in that laboratory is a figure you’ll never match on the road.

The thing is, if you really try, you will. Our chief sub editor, Tim Dickson, frequently beats a test car’s combined cycle figure but admits sometimes you have to drive “extremely anti-socially” to do it. In the MPG Marathon run by Fleet World Group, they do just that, too, bettering the combined figure by 10-15% on average.

But if you don’t beat it, is it so shocking? “You wouldn’t expect to match a car’s quoted 0-60mph time on the road,” says Dickson, because like the combined figure, it’s set in optimised conditions.

But, yes, the NEDC is outdated and needs replacing. It needs to be longer and more varied so it’s harder to optimise a car for it and, hopefully, it’ll bear more resemblance to actual driving. But car makers will still try to perform as well as they can – and there isn’t a whole lot we can do about that.

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Comments
9

16 October 2015
Why not stop publishing actual MPG numbers and instead group the cars into the VEL road tax bands and give them a star rating only.

That way people won't have a measurable expectation only a guide as to which cars are likely to be more or less economical.

I agree with the article's writer about combined mpg figures... My BMW 3.0 petrol consistently matches or exceeds the combined figure!

I think it was Clarkson who said "it's not what you drive, it's how you drive it".

16 October 2015
Remember in the 70's when I purchased a new mini and MG Midget you got official mpg at think it was 30mph,56mph,75mph .At least you got a better idea in real world driving ,then the Eu come in and we scrap our system and replace it with a bureaucratic , incompetent mess.Lets hope we leave the crumbling EU .

16 October 2015
For added context, a 2 litre family saloon (0-60 11 secs, top speed circa 105mph) could be expected to get overal mpg in 28-32 mpg range. I don't think there was the same fixation about mpg then, though. There were no mpg gadgets in the instrument panel. I do remember during the fuel crisis with 50mph blanket speed limit in UK our mpg did improve a bit. Regulations probably start out with good intentions, but they need to keep pace with developments and manufacturers art forms in meeting/beating them. Let's hope that happens soon.

16 October 2015
@ Ski Kid. I'm inclined to agree, though actually the test comprised an urban cycle (carried out on a rolling road) in addition to the two steady speed measurements. Nice and simple, plus relatively easy to check if your car had an accurate speedometer and trip computer. But I think that the main difference was that the manufacturers were a little more honest back then because there was less incentive to bend the rules. The problem we have now is that the test is no longer a good comparator between different car models.

16 October 2015
autocar wrote:

Our chief sub editor, Tim Dickson, frequently beats a test car’s combined cycle

I remember when I was able to beat them too (quite easily with VW's funnily enough), but Tim is more than welcome to drive my 1.6tdi Focus. I very much doubt having four Sumo wrestlers push my car downhill at 56mph with the engine switched off and a tail wind would see Ford's quoted figure of 67mpg on the combined cycle.

16 October 2015
Take 5 cars on 400 miles drive at normal speeds incorporating motorway, urban crawl and mid-speed A roads, to make it fair get them to follow each other as best as possible. Compare the fuel used to official figures and hey presto an article that judging by a lot of the posts on this website people would be interested in. My choice of cars would be a petrol and diesel Golf, 3 cylinder Fiesta, a fairly fast 3 series BMW and a Mazda 2

 

Hydrogen cars just went POP

16 October 2015
@xxxx

Autocar's sister magazine, What Car, does do real-world testing and say that on average get 20% less mpg than officially stated.

But worth remembering too that the VW issue is about emissions, not economy!

16 October 2015
Their long term tests are worth watching too. Who would have thought that a Panamera hybrid has given 38.5mpg average over the test period, and yet a 1.2 Fabia has given only 37.5mpg. The Peugeot 308 1.2 has given 46.1mpg, and yet a 1.0 Twingo only 41mpg. And a Lexus NX300h 32.6. Not all identical running conditions of course, but very much real world! Confusing? Now that would make an interesting 400 mile group test, as @xxxx suggests, with Tim Dickinson getting to drive the car that is furthest away from its official combined figure in Whatcar tests. And one more thing, the test would have to include an average speed minimum, to reasonably reflect that most of us probably have to get somewhere within a certain timescale.

16 October 2015
March1 wrote:

But worth remembering too that the VW issue is about emissions, not economy!

The MPG figure is calculated from the CO2 emissions test so it wouldn't surprise me if CO2 targets and lower tax bands were the main driving force behind these exaggerated MPG figures.

Quote:

But car makers will still try to perform as well as they can – and there isn’t a whole lot we can do about that.

Of course there is, they wouldn't do it if more people disliked it than liked it. Right now it benefits them because of the lower tax and the fact that the motoring press is almost universally happy to quote those figures as reality. With tax changes from governments, like the one the UK has planned, and the non-publication of suspicious figures by the motoring press until they'd been tested and verified we'd soon see it drop back down to accurate levels

There is perhaps a case for publishing 'best case' figures alongside typical ones to encourage people to improve their driving but any sort of government mandated figure that can't be challenged by the customer has to reflect typical use first.

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