Fuel consumption tests
I'm glad to see the DT taking up the cause for improving the completely unrealistic 'Official' consumption figures. As you say, manufacturers are simply designing to the test. I wrote to my MP and DfT pointing out the failures of the test and at least they replied to say change was afoot. The main failings are:
1. Temperature - how often do people drive to work in the UK at 20-30degC ambient?
2. Aerodynamics - the test is done in a lab!
3. Max speed - only 50mph or thereabouts, how can that reflect motorway driving?
4. Power variability - the test follows a speed profile, so more powerful cars will be hardly breaking into a sweat compared to, say, a small 3-cylinder.
1. Temperature - how often do people drive to work in the UK at 20-30degC ambient?
2. Aerodynamics - the test is done in a lab!
3. Max speed - only 50mph or thereabouts, how can that reflect motorway driving?
4. Power variability - the test follows a speed profile, so more powerful cars will be hardly breaking into a sweat compared to, say, a small 3-cylinder.
Asked on 2 May 2012 by wiggers
Answered by
Honest John
It's not the DT. It's www.honestjohn.co.uk/realmpg We now have 25,000 real driver inputs. But we are not complaining because complaints will only bring more realistic tests that will show higher true CO2 and mean higher taxes. We merely want to provide a means of showing carbuyers a realistic assessment of the fuel economy that cars are likely to achieve in average everyday motoring. In fact, in real life, the real life figures show that drivers are more likely to get better economy than the EC figures from big engined cards than they are from small engined cars.
Tags:
technical issues
Looking for a garage you can trust? Honest John's Good Garage Guide has thousands of reader recommended garages, plus how-to guides and tips on servicing.
The Good Garage GuideSimilar questions
I am trying to find out if anyone has the answer to this question. My daughter has a 206 1600 HDI. The car went into limp mode - it will not go over 3000 rpm, it runs OK, will drive through the gears but...
I have a 2016 Vauxhall Corsa 1.4 petrol. Can you please tell me if it has a cam belt or a cam chain?
Also, when accelerating up through the gears from cold, there seems to be an exhaust boom or resonance...
Does the Honda Jazz 1.4 ES CVT have a chain or belt cam drive?
Elsewhere on 
