how to save £500 a year (even if it does mean driving at 20mph)

Record prices at the pumps could succeed where 6,000 cameras and millions of pounds in road-saftey advertising have failed for decades – by securing compliance with the speed limit.

Driving more slowly will save drivers up to £500 a year in fuel costs, according to a study, which reveals that the most efficient speed is much lower than most people think.

With the average price of petrol at £1.17 a litre and diesel at £1.30 – 20 per cent higher than a year ago – the financial incentive to obey the speed limit has never been greater.

Car manufacturers suggest that the optimum speed for fuel efficiency is between 50mph and 60mph and a recent survey found that two thirds of drivers believe this to be the case. But the study, commissioned by What Car? magazine and based on five cars of different sizes ranging from a 1 litre Toyota Aygo to a 2.2 litre Land Rover Freelander, found that the most efficient speed was below 40mph for all five and as low as 20mph for two.
Above 40mph, fuel consumption increased sharply and by 90mph the miles per gallon had halved on average.

The study comes as the Government prepares to put in place emergency measures to prevent a strike by Shell oil tanker drivers from creating fuel shortages across the country. Downing Street urged drivers yesterday not to panic buy, which would cause shortages even if fuel deliveries continued as normal.

The study, by Peter De Nayer, a former AA fuel efficiency expert, involved fitting cars with a fuel flow meter and testing them at Millbrook proving ground in Bedfordshire. He found that a Citroën C4 1.6 diesel achieved 99.6mpg at 20mph but only 29.3mpg at 90mph.

The average car consumes 38 per cent more fuel at 70mph than it does over the same distance at 50mph. At 60mph it uses 34 per cent more than at 40mph.

The average driver travelling at 90mph on a motorway will spend £1.20 more on fuel every eight minutes than a driver travelling at 70mph. The 90mph driver will have travelled farther in that time but will still be spending 40 per cent more per mile than the 70mph driver.


Ben Webster,

full article