I have started cycling to work.  I know you’re wondering what this has to do with a motoring website, but bear with me.  The more miles you cover on a bicycle the more you find yourself reluctant to stop, only because of the resulting loss in momentum and the extra leg power required to get moving again.  This is why as a cyclist you find yourself weaving through zebra crossings and (don’t quote me on this), even looking at traffic lights to see if it’s safe to slip through that red light. Really doing anything to avoid stopping.

As we count down to Team Green Britain day on the 10th July it seemed perfectly timed that I was recently treated to an eco driving course from BP.  Now I’ve written enough guides, and attended enough courses on driving economically that I felt confident of my abilities to drive a car in an environmentally conscious and fuel efficient manner. 

The course was a pre-planned route around London that took about 30-45 minutes and was designed to include areas of congestion as well as enough driving room to cover a few miles at the same time.  I was accompanied by Chris, who works for BP’s PR Company and a guy called Anthony from BP’s testing crew, based at Millbrook in the Midlands.

Having read and written driving guides myself, I’m well aware that one of the most important things to keep in mind is that keeping up a steady speed is the best way to get the most out of each thank full.  The Institute of Advanced Motorists recommend keeping a careful watch of what’s going on down the road, as well as the part of the road that you’re driving on.  This makes great sense as you can plan for what’s going to happen a bit down the road.  This enables drivers to anticipate what’s going to happen before it does and they can make the transitions between what they’re doing as smooth as possible.  This means less energy is lost in getting speed up and then stopping, which is where most fuel is wasted.

As we drove around I was careful to make sure that I got up to speed in a steady, safe manner and then eased off the throttle to run the car at a slow cruise.  Our route took us from Waterloo, along Union St towards London Bridge and then into the City, heading to Tower Bridge.  While sitting in traffic I was keen to use the Ford Focus’ tick-over energy to make sure I was in the perfect place to maximise the most miles for BP’s money.   It was during this time that Anthony started discussing the newest weapon in my eco armoury, inertia.  It takes significantly less energy to increase your speed than to get moving from a standstill.  Anthony pointed out that it’s very common to see lorries stopping a number of car lengths from traffic lights, and then crawl up to the junction, using the power generated as the engine idles.  This gives the lorries some inertia, or momentum, which makes the change from standing to motoring less painful on the fuel tank.  As Ant commented, lorry drivers make more money if they use less fuel, so they’re gonna know every trick in the book.

As we drove back over Tower Bridge and back around the ring road, heading for Lambeth and then waterloo, we discussed where most fuel is used.  I was not especially surprised when Anthony said that higher revs offer an inefficient use of fuel but I was surprised to find out that loss of efficiency started just north of 2,000 revs.

We got back to Waterloo and went through the results.  I’d averaged a pretty lean 30 mpg, which is respectable in city traffic , so I was reasonably pleased, although could surely have done better with a more inertia based approach.

Before we parted company Chris took a picture of me for posterity and he and Anthony drove off (economically), into the sunset.  I was left thinking about how important it is to keep your speed up.  When I’m running out of breath trying to get up Creek Road and get through Deptford on the way to Surry Quays, I’m looking to avoid stopping at any cost.  The nature of momentum says that you should be trying to retain some level of motion at all times when behind the wheel it will help reduce your motoring costs and requires a small adjustment in the way that approach traffic lights and junctions.

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