Interesting topic.....remember, ADR figures are from experts driving so quite unattainable to most...
Fuel, load (ie weight) of car, air con usage, tyre pressures all play a part in economy...but the big thing is the driver. Are they a leadfoot or a nanna ?
To the person who compared a crv to a six for fuel economy...dream on....A crv takes 45 litres in the tank, so 400 to 450 for driving in the city is pretty good... a dunnydore might also only get 400ish k's, but not from 45 litres...more like 60+....
I have our CRV tyres at higher pressure (38 psi +) and as well as increasing tyre life, fuel economy get a bit better.
Using higher octane fuel doesn't really do much, especially considering the usual price difference. It is hardly only a few cents more. The 10-20 cents price hike doesn't make it worthwhile for sitting in city traffic, only highway trips....