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Reduce fuel consumption but not add journey time – can it be done?

26 Jun 2012 at 15:54

Reduce fuel consumption but not add journey time – can it be done?

What difference does 10mph make? When you’re sat behind a slower moving driver at 60mph in the outside lane of the motorway, you might think a lot.

It’s a familiar illusion: being stuck behind traffic makes you feel like your destination is slipping away as the ETA on your sat nav drops further and further behind.

However, the reality is much different, suggests new evidence. Indeed, cutting your speed might actually save you some money, as well as see you arrive to your endpoint perfectly on time.

According to DriveGain – the builders of an iPhone app that helps you save fuel as you drive – lifting the throttle slightly and travelling at 60mph can save you up to 10 per cent in fuel, yet only add two minutes to your journey time compared to travelling at the maximum 70mph UK speed limit.

Drop to 50 and your fuel consumption will improve by a further five per cent, yet only another two minutes will be added to travel time. These are considerable saving in fuel (and, thus, money), for minimal differences in overall journey time. The tale about the tortoise and the hare may indeed have some resonance…

To some people, of course, a reduction to 50mph would be a gear change too far. However, to others, it’s actually more commonplace than critics of lower speed limits may realise. For example, motorists in Warwickshire are subject to a near-blanket 50mph limit on all single carriageway roads.

This county-wide scheme was met with annoyance when it was first introduced, but with the way fuel prices are rising, would the residents of Warwickshire give up the five per cent fuel saving and go back to 60mph? On the basis of this new evidence, perhaps not.

There’s no magic to it, either. It’s simple dynamic science. Driving at speed is just one part of driving. Dealing with traffic queues, traffic lights, junctions and roundabouts is another part of it: tackling all this once you exit the motorway easily eats up any advantage you may have pulled out through driving fast.

Simply put, driving quickly only gives you an advantage in an ideal world. Real life driving conditions quickly neutralise any advantage. It’s the smart drivers that that realise this who are saving money.

Team it with some canny eco-driving and you might actually further your range on one tank of juice and still not get to your terminus any later than the hot head changing lanes at speed and getting caught by traffic.