Quote Originally Posted by wai View Post
The thing is that the published fuel consumption figures are run in accordance with a standard. This makes sure that the conditions and cycle that one vehicle operates will be exactly the same as another vehicle. As such, the figures can only ever be used for comparative purposes, and even here for the same type of vehicle only (i.e. passenger cars or wagons or vans)

Fuel consumption calculated in everyday use can vary tremendously because of the number of variables like wind (speed and direction), temperature, tyre pressure, road surface, traffic, a/c use, windows up/down, etc.

By the way, this is also why there is no correlation between official test emissions and emissions measured using a on-standard drive cycle that has not undergone any verification process.
Exactly!
I can equal the 'country' figure simply by driving gently on a flat road with no wind and no traffic.....certainly not realistic.
But from Jan 2016 a more realistic testing procedure will apply and I imagine THAT will involve more realistic acceleration and higher load at speed.
There is to be a 'world' standard applicable form 2017 which should mean we don't get the dirty hand-me-downs any more.
Hard as the tests will be, the industry should, at least, have simply one emissions rule to satisfy.