Comments on: Vehicle fuel efficiency - units matter

by: John Frewen-Lord

Tue, 08 Jul 2008 19:39:02 +0000

I keep my car’s digital computers in metric, as, having lived in Canada so many years, L/100 km means much more to me. That is what people there ONLY use these days, although was a time when some people did a double conversion to miles per (imperial) gallon, notwithstanding having bought their fuel in liters and their car recording the distance travelled in km. Those days are now long gone, and people there only understand L/100 km. Today, even in imperial UK, I find L/100 km much more useful and meaningful, and mentally convert all my car journeys into km.

by: Ezra Steinberg

Sun, 29 Jun 2008 18:43:38 +0000

Once again we see the integrated nature of the problem and how the anachronism of Imperial road signage continues to serve as a key road block (pun intended) to completing metrication where it counts: in the daily mental activity of the citizenry.

by: philH

Sun, 29 Jun 2008 09:53:18 +0000

It’s not a case of litres/100 miles being easier to understand than litres/100 km it has more to do with not knowing distances in km in the UK.
Motorists are forced to think in miles because of road signs, road atlases and car instrumentation as well as most other sources of travel information.
We cannot expect the average UK motorist to make the mental effort it takes to think in km in those circumstances.

by: Michael Hawkshaw

Sat, 28 Jun 2008 22:11:37 +0000

I’ve never bought fuel in gallons. In fact, I’ve never bought anything in gallons and never seen anything for sale in gallons. I can only use mpg to see how more fuel efficient my car is compared to other cars, I’ve never used it to see how much fuel I would use on a particular journey.

Introducing “gallons per mile” would be as much use to me as mpg is. Now L/100km - that is useful, and I can use it to quickly calculate how much fuel I’m likely to need for a particular journey. It would also make me think twice about making a journey by car. Shame the information displayed in my car can’t help me with this.

by: Daniel

Sat, 28 Jun 2008 12:00:20 +0000

Quote: Admittedly there is still the issue that we use miles for everything so the public would understand gallons per miles better, though perhaps litres per 100 miles might be a compromise moving us in the right direction?”

Litres per 100 miles would be a bad compromise. It means getting use to one set of numbers then when road sign metrication finally happens having to get use to a new set in short time. The better compromise would be to call it litres per 62 miles, at least this way the numbers are the same as litres per 100 km.

by: Alex Bailey

Fri, 27 Jun 2008 12:01:59 +0000

I get the feeling that many British drivers actually work out the figure as “miles per metric gallon” (meaning 1 gallon = 5 litres) since the maths is clearly easier and most drivers under 30 and quite a few under 40 probably don’t ever remember buying petrol in gallons anyway! This would clearly mean that figures given by manufacturers in new car brochures and other advertising bear little resemblance to what drivers actually experience.

I switched to using L/100 km a few years ago and merely multiply the distance on my odometer by 1.6, I’ve found it much easier to calculate fuel costs and have a much better handle of how far I can drive on any given quantity shown on my fuel gauge than I ever did using mpg.