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STEP on the gas if you want to cut your fuel consumption. That’s some of the
advice you’ll get from a new dashboard device that tells you how to drive more
efficiently. It could reduce your fuel costs by a sixth—and you’ll still
get from A to B as quickly as before, say Dutch and Swedish transport
experts.

People often believe that you have to drive slowly to be fuel-efficient, but
that’s not the case, says Mark Dougherty of the School of Transportation and
Society in Borlänge, Sweden, which supervised the fuel-efficiency project.
“They think to accelerate gently will get a better fuel consumption,” he says.
“That’s basically wrong.”

This fallacy was the idea behind a host of dashboard devices that appeared in
the 1970s in response to the oil crises. They included crude miles-per-gallon
meters, for example, but they only made tiny improvements in fuel efficiency,
says Dougherty.

The problem was that such gadgets didn’t take into account the context of
each driving manoeuvre. So the new device tries to offer both tactical and
strategic advice on your driving, rather than just flashing a light at you when
you over-rev the engine. “It doesn’t just tell you that you drove badly, it
tells you how to improve,” says Dougherty.

The system was developed at the University of Twente in Enschede, the
Netherlands, by Mascha van der Voort and Martin van Maarseveen. It monitors
speed, steering angle, clutch, braking force and gas pedal position. For each
manoeuvre, such as accelerating, braking and turning, there is an optimal fuel
consumption, explains Dougherty. By studying the behaviour of the car, the
device can work out whether your input is fuel-efficient each time you perform a
manoeuvre.

A display on the dashboard then offers bits of advice such as: “Shift earlier
from second to third gear”, “Harsh braking manoeuvre!” or even “Accelerate more
rapidly”. But it also analyses groups of manoeuvres in context to give you more
general advice, such as recommending that you try to keep more distance from
other cars so that you don’t have to brake so often.

Rather than distracting you during manoeuvres, the system waits until later
before offering suggestions. In simulated driving tests the researchers found
that there was an overall reduction in fuel consumption of 16 per cent,
considerably better than the 9 per cent reduction drivers managed without help.
“And in the field trials there was no difference whatsoever in journey times,”
says Dougherty.

“Given that cars are engineered so efficiently these days, driver behaviour
is the big variation in fuel consumption,” says John Stubbs of Britain’s
Automobile Association. People think they can hear when it’s time to change
gears, he says, but to do so efficiently requires great skill. “Even trained
rally drivers find it difficult.”

“The engine operates at peak efficiency when it’s at about two-thirds its
power output,” says Dougherty. “The bottom line is: to get better efficiency you
should change up a gear earlier, at relatively low revs per minute,” he
explains. “But don’t be afraid to give it some gas.”