I beg to differ but I think each point of view has it's merits. My motoring is mainly urban, with the occasional and rare longer run, like today. With urban I can achieve, if I want, up to 40mpg, thus I can compare that with official figures. Todays drive was mixed, thus I compare it with a official mixed figure as well.
Taking a long term average and mixing all the conditions the car has been in and averaging them cannot be compared to official figures.
However if I was to take today's figure and my urban one the average would be around 42.5mpg. If I was take my lowest urban mpg, 30, and add it todays it would be around 37mpg.
Even if you are happy to take the long term average mpg that then could not be used to compare with others as the questions usually are, 'what mpg can it do around town, or, 'what can it do on a long run'. Unfortunately yours would only be a average of them both thus could not be used to answer those questions.
Don't get me started about the different driving conditions that can drastically affect mpg either. Ambient temps, engine temps, distance travelled, hills climbed, number of corners taken all add up. Then there is the driver who probably has the most influencing factor. We are not all the same, we don't all drive cars the same way and with the same driving conditions. So the conditions do need to be separated, ie urban and mixed, and not merely averaged out, to at least to get at a comparable figure.
Taking a long term average and mixing all the conditions the car has been in and averaging them cannot be compared to official figures.
However if I was to take today's figure and my urban one the average would be around 42.5mpg. If I was take my lowest urban mpg, 30, and add it todays it would be around 37mpg.
Even if you are happy to take the long term average mpg that then could not be used to compare with others as the questions usually are, 'what mpg can it do around town, or, 'what can it do on a long run'. Unfortunately yours would only be a average of them both thus could not be used to answer those questions.
Don't get me started about the different driving conditions that can drastically affect mpg either. Ambient temps, engine temps, distance travelled, hills climbed, number of corners taken all add up. Then there is the driver who probably has the most influencing factor. We are not all the same, we don't all drive cars the same way and with the same driving conditions. So the conditions do need to be separated, ie urban and mixed, and not merely averaged out, to at least to get at a comparable figure.