[tla]

http://www.guardian.co.uk/environment/2013/mar/14/car-manufacturers-manipulating-fuel-efficiency-tests

No wonder the mileage they achieve is so low. 

[beerman]

You will always have this where the manufacturer supplies the car. Perhaps the test people should pull up at the main storage yard and pick a car and do the test on that one (still it wouldn't take much to manipulate a shipment I suppose).

The test should then be repeated, by the test people picking a car from the dealers yard, and testing that.

It would reduce the ability to manipulate the test.

[AlanHo]

I am guilty of posting on this forum a list of ways that manufacturers get the best out of the official government test – and most of the items I have previously quoted are included in the list given in the article. One important item they have omitted is that it is common practice for the tyres to have their tread ground to a perfectly true circle and smooth surface

However – the tests is carried out on a rolling road in a temperature controlled environment – and not on the open road. Hence I fail to see the relevance of them listing high altitude, aerodynamics and taping over indentations or protrusions in the bodywork and changing gear ratios (which is not allowed).

I subscribe to the view that the government test is unrealistic -  but having said that – I am not sure what would make it a true representation of real life because we all have different driving patterns and habits.

[Ace Demon]

However – the tests is carried out on a rolling road in a temperature controlled environment – and not on the open road. Hence I fail to see the relevance of them listing high altitude, aerodynamics and taping over indentations or protrusions in the bodywork and changing gear ratios (which is not allowed).

It seems the disconnect occurs because the rolling road on which the test is done is programmed with resistance values supplied by the vehicle manufacturer. I presume there are checks to make sure they are not actually inventing resistance figures but not enough checks are being done on the tricks to minimise them.

[Aussie Keith]

Sounds like a lot of trouble to gain some marketing brownie points. Which if there's a scam involved in obtaining them is likely to generate some very poor press. Its more likely the test cycle does not represent real world driving conditions which was also acknowledged in the article.

The fact that our own mileages can vary significantly at the lower end owing to driving style and local conditions (rolling road might be considered a local environment) is a clue I think.