MSE News: Government miles-per-gallon car figures 'unreliable' 27 April 2012 at 9:34AM in Motoring 67 replies 6.2K views

Former_MSE_Helen

This is the discussion thread for the following MSE News Story:

"Official government fuel figures overstate just how many miles cars can do to the gallon, it has been claimed"

Read the full story:
Government miles-per-gallon car figures 'unreliable'

verityboo

Not really news, just another report confirming what people knew - the manufacturer tests carried out under ideal conditions give better mpg than people achieve in the real world

agrinnall

In what way are they 'Government figures' anyway - surely they are figures provided by the manufacturers and just compiled by the Department of Transport?

fivetide

Yep a definate "no excrement Sherlock" story.

In other news, grass green, sky blue and later, night to follow day.

5t.

Strider590

Well.... To be fair it's been in the govts interest to not challenge the manufacturers claimed MPG figures, many people wouldn't be buying cars and thus feeding into the coffers if they didn't think their potential new car would give them some benefit in fuel consumption.
Why else was it so important that the govt set about creating the scrappage scheme a few years back?

They are of course idiots anyway, if they think buying a new car can save them money at all.... Even if the old one did 35mpg and the new one 50mpg.

RDG

Yeah this really isnt news, manufacturers make claims for figures but they will have done the test under very specific circumstances that are probably impossible to achieve in reality. Hence I always look at the combined figure and deduct 10% for possible real world driving.

Although on my commute I do get the manufacturers claimed figure for the combined cycle which is what i would describe my journey as. It all depends on how people drive it should be treated as a potential figure. In reality if you drive the right way you can exceed these manufacturers figures in some cars.

adamc260

When I buy a car I look at Urban and assume that will be about the average I get... maybe a bit higher. That way i'm looking at the bottom end of the scale.

Strider590

adamc260 wrote: »

When I buy a car I look at Urban and assume that will be about the average I get... maybe a bit higher. That way i'm looking at the bottom end of the scale.

Reality is often around 10% less than the "combined" figure.

jeferey

We've known this for ages! - as Strider said most people get less.
I hypermile to get 30+% more than combined figure for my car.

agrinnall wrote: »

In what way are they 'Government figures' anyway - surely they are figures provided by the manufacturers and just compiled by the Department of Transport?

The secrets behind official mpg v real life mpg

colino

The only point for these tests is to compare other cars in the way they have performed in the same test. So you can see with your reading eyes on that a Panda is more economical than a Bentley, that's their only value.
My wifes car persistently hovers around 23mpg and if I take it for a week the average for that fill will be 31-32mpg. Same car, same roads, just different driver.
The manufacturers don't fake the figures (albeit the one production car they test will be in finest fettle), as they aren't so daft as to be officially sanctioned, but real life will always be different.

fivetide

Also, lets not forget the tests are performed in a lab and often the engine isn't even in the car.

Nothing like realistic conditions.

that said, Watchdog did a big piece on this a while ago and followed a group of people on an mpg challenge. One chap had actually got more than the official figure from his smart car!

5t.