Car Choice: Fuel for thought

On the road, it can be hard to match the carmakers' economy figures. James Ruppert looks at the performance data for two models that claim to be the greenest

Julian Gregory, 65, is retired. With a budget of £4,000 to £7,000, he wants a second-hand car for his wife and himself. Low emissions and fuel consumption are essential, and it must be able to cover good distances - Cornwall to Yorkshire, say - very capably. Julian is not impressed by 50mpg and discounts the Honda Jazz, which often features here. He also seeks clarification on stated emissions figures.

ulian wanted to know whether 64mpg in a Fiat Panda is a realistic figure. It's an interesting question, in light of a recent What Car? investigation. They carried out independent tests and found that, on average, we refuel our cars 8 per cent more often than the figures say we should.

The magazine drove 1,143,197 miles in 58 cars and found that all but three were thirstier in the real world than in the makers'.

Thing is, there's no evidence to suggest that the car manufacturers are actually lying. The tests are conducted by the manufacturers and - even more troubling - are performed in laboratories. Manufacturers can therefore run cars in very controlled conditions, in circumstances that obviously make the engines perform at their best.

As a journalist, I admit to using their figures because there simply isn't anything else to use. Indeed, the Government's own Certification Agency oversees the tests. It is obviously difficult to replicate real conditions, but maybe they should try to do so in each country in Europe.

So Julian is right; treat mpg figures with caution. Essentially, they are only a guide. What Car? reckons that a downward adjustment of 8 per cent overall is fair. And I haven't even got on to CO2 figures...

A CAR FOR THE HEAD

Julian needs the most fuel-efficient and lowest CO2 emissions figures to meet his criteria. In theory, the Smart For-two ought to be the best buy, although Julian is probably aware that it is a two-seater with minimal luggage space. Otherwise, the Smart is an very able small car with lots of modern safety features, such as airbags, electronic traction control and ABS brakes. Best of all, the Smart never feels out of its depth on the open road.

It should return 60mpg, according to official figures, which could be adjusted to 55mpg on What Car?'s 8 per cent basis. Emissions are not too bad; the Toyota Prius, the green benchmark, registers 104g/km for CO2, whereas the Smart is 113g/km.

Prices for older used City Coupé examples are down to £3,000, although a good 2005 Fortwo in basic Pure trim need not be more than £5,000 with less than 10,000 miles on the clock. There is an electric battery-powered Smart - zero emissions - but it will only cover up to 70 miles on a charge and is initially only available to corporate customers.

CAR FOR THE HEART

Julian sounds like a hard bloke to please, but the perfect combination of low CO2 and high mpg has to be the Toyota Prius. Unfortunately, the What Car? feature placed the Prius top of its list of the 10 cars with the worst mpg variations. Instead of the official 65.7mpg, it only returned 52mpg. Good enough for Julian, I wonder?

The older model, which he could afford, may not even be that fuel-efficient. A 1999 Prius with 50,000 miles would be about £6,000 from a dealer. The Prius would certainly handle longer journeys, but it might struggle to give Julian the mpg he needs on shorter journeys.

Julian asked about the cleanliness of diesels. Actually, their CO2 output is less, while mpg is at least 25 per cent better. However, they can emit more particulate black carbon. That isn't good for the environment, the boffins say, and may even accelerate global warming and increase the risk of cancer.

The thing is, though, that the science is actually quite shaky on much of this, and the majority of the particulates we breathe in are spewed out by industry. I'm sure Julian knows all the arguments.

CAR CHOICE

Please write to Car Choice, Features, Independent House, 191 Marsh Wall, London E14 9RS, or e-mail James Ruppert at carchoice@independent.co.uk, giving your age, address and contact number, and details of the type of vehicle in which you are interested and your budget.