Have you been cheated?
Car buyers misled by claims of fuel efficiency
Research from Emissions Analysis has found that UK drivers are being short-changed, with claims of fuel efficiency overstated by up to 36%. Even more shocking perhaps is the revelation that the smaller eco-cars are among the worst offenders.
With the cost of running a car being one of the largest outgoings for drivers, automobile efficiency has become one of the most important factors in buying a new car, with buyers typically looking to the model’s MPG figure to make an informed choice as the more miles it can drive, in theory the cheaper it will be to run.
But an analysis of 500 cars true performance on the road by Emissions Analytics has called into question figures that are quoted by manufacturers – finding that the actual performance of a car tends to be 18% lower than is claimed, with the largest variance between official figures and real life performance seen among cars with engines of 1 litre.
With claims of 60mpg and higher, many people buy these smaller engined cars in the belief that they’ll make real savings on fuel but the reality of the situation seems to be that they only achieve 3mpg more than the average of all the cars tested – including petrol-guzzling performance cars. The below graph spells out the full findings from the analysis:
| Engine size (litres) | Variance | True mpg |
| 0-1 | -36% | 38.6 |
| 1-2 | -21% | 46.7 |
| 2-3 | -15% | 45 |
| 3-4 | -14% | 35.7 |
| 4-5 | -15% | 25.4 |
| 5+ | -1% | 23.5 |
| Average | -18% | 35.8 |
Source: Emissions Analytics
You may be wondering how companies get away with this kind of misleading data. In the UK the fuel economy of a car is measured by the New European Driving Cycle (NEDC) – an independent cycle used to test emissions and efficiency – but the test fails to take into account rapid accleration in regards to MPG and are done in controlled circumstances which aren’t relevant to normal road driving and conditions such as road works, traffic and fluctuations in speed.
“The NEDC test has relatively few episodes of acceleration and those that it does have are of a gentle nature. This is predominantly why smaller engines appear to perform well in tests, until they are on the road and every rev suddenly burns through the fuel,” says the report.
Based on the test results, Emissions Analytics recommend that a 1-3 litre engine that will provide around 45-46 MPG and give you the best fuel efficiency, so maybe think twice the next time you look at the engine size of your potential new car.
