12 Aug 08
Conclusion
In short, buyers cannot trust the fuel economy figures as quoted: as a rough rule of thumb, at the levels of fuel economy of the cars we tested, deducting 10mpg will get a more realistic reflection of the car's fuel consumption.
And don't forget the corresponding rise in carbon dioxide emissions. Our tests suggest that all the cars we studied should really be classed in Road Tax Band C. The current Band B ranking is good news financially, but if you have bought a 'green' car to do your bit for the environment, it's fair to say that it's not as eco-friendly as you might think.
Our aim was not to point the finger at car manufacturers, but to show that the official government-standard test process, carried out in a laboratory, is too simplistic to reflect real-world driving conditions.
Although manufacturers work to the European directives - it has to be noted that they aren't exactly calling for change.
The carmakers argument about consistency is still misleading, though - if the official consumption figures say you'll get 60mpg, you should expect to get 60mpg.
4Car feels that the official testing procedure needs to be reformed to include road driving and more realistic representation of real-life motoring. Car buyers base much of their decision on a car's fuel economy figures, so the industry should be doing more to ensure that these figures are as accurate as they can be.
