So you thought that small cars were more economical than big cars?..... Think again.
Research by Emissions Analytics discovered bigger cars were actually
closer to their claimed fuel economy figures.
The data is derived from the driving of 500 vehicles, 250 petrol and 250 diesel, for
three hours on British roads to give a more realistic representation of
real-world use. It transpired that on average manufacturer fuel economy
figures were 18 per cent lower than advertised in brochures.
Cars with the smaller engines showed the biggest discrepancy, with vehicles in the
0- to 1.-litre category achieving 36 per cent few miles per gallon. That
worked out at 38.6 instead of 60.3mpg. 21 per cent fewer miles were
achieved In the 1- to 2-litre category, averaging 46.7mpg instead of
59.1.
Larger engines in the 2- 3-litre category came out as the worst fuel
guzzlers, unsurprisingly, but the claimed figures were only 15 per cent
out on the claimed ─ 45 instead of 52.9mpg.
The difference is down to how manufacturer
estimates are worked out. The manufacturers test in laboratories with low rates of
acceleration and slower speeds. Unsurprisingly this method will never give an accurate
representation of real world day to day driving.
“For maximum fuel economy you should look for a one to three-litre
engine, as these will return around 45-46mpg. To avoid being too
disappointed with the result, pick a two to three-litre vehicle as it
will be only 15 per cent worse than you were told you could achieve,”
Emissions Analytics said in a newsletter.
Stephen Glaister - RAC Foundation director is concerned that the findings show that
consumers are being misled: "These astonishing figures only fuel the
debate on the worth of official mpg data. Well over two million new cars
will be sold in the UK this year, with small vehicles topping the sales
chart. But how many drivers will actually get what they think they have
paid for? The answer, in terms of fuel efficiency, must be not many.”
