Driving data

It’s been quite a while since I last drove a gas-guzzling car. My little car was chosen for fuel-efficiency and low CO2 emissions. So I thought I would look good when I did my “driving carefully” experiment.

At first it wasn’t difficult to get into the mind-set of thinking ahead, braking less and driving more slowly, and for the most part I did OK. Trouble was, there were a few times when I was late for an appointment and I reverted to my old ways. Also, most of my journeys were relatively short - 10 miles or so – and on roads with roundabouts and traffic lights, which I’m sure contributed to the less than brilliant result.

So – what was the outcome? I filled the car a week or so ago and have driven 304 miles. When I filled up a couple of days ago I put 38.3 litres into the tank.

So on 38 litres of petrol, or 8.36 gallons, I have got about 36 miles per gallon out of the car – hardly a star performance.

Some cars let you see your average miles per gallon as you are driving, and that must be useful. I don’t have that gadget on my car. However I will try and monitor my petrol consumption over the next few tanks to see if I can improve on 36 mpg.

This calculation wasn't particularly intuitive. Looking up how many litres in a gallon wasn’t difficult, but it took some proactive thought. Even the new (in so many senses of the word) Toyota Prius, boasts its fuel consumption as 72 mpg, although they know all their customers will be filling up in litres. If we are going to buy fuel in litres, shouldn’t we measure its performance in litres?