Fuel Economy claims

When we see new car advertisements in magazines or newspapers often we see claims on fuel economy figures published in bold to attract prospective car buyers. It is good way to promote the car's fuel economy but is it realistic? can it really be matched in the real world?

Japan and Europe each have their own way to test fuel economy and will result in different claims. All car manufacturers will naturally try to get the best result possible and publish the lowest figure. However, it is very often that we drive in less than perfect conditions to enable us to match the claimed fuel economy figures as claimed in the publications.

Several key factors contribute to us not be able to match the claimed fuel economy figures:
- using air conditioning
- driving with under inflated tyres (very common problem)
- carrying more weight in your car than you should (meaning you have your golf bag and other items in the trunk)
- driving faster than the ideal fuel economy speed
- getting stuck in heavy traffic often
- high ambient heat
- brisk acceleration

Fuel economy claims should be used as just a rough guide only. It does not necessarily mean that you will be able to achieved the claimed fuel economy. In an ideal world with ideal conditions there is the possibility of achieving the claimed figures but we don't live in an ideal world with ideal driving conditions.

Honda in US was recently sued over false fuel economy claims. The fuel economy claims were far lower than what was actually achievable by an ordinary driver. This law suit set an example and a warning to car manufacturers to not simply claim fuel economy figures and only state a realistic fuel economy figure. To be fair to the motoring public, only a very small percentage of drivers will even attempt to drive according to best fuel economy practices on a daily basis.