[briank]

So I got my spreadsheet out and low and behold it works out that Vehicle A going from 10 mpg to 12 mpg at X miles/year will give the same reduction in number of gallons/year as Vehicle B going from 30 mpg to 60 mpg, when both vehicles travel the same number of miles. This seemingly paradoxical calculation is probably well known on this forum but I think Joe Public and Joe Politician or even Consumer Reports do not seem to know this. When you hear Consumer Reports saying A/C use give about a 1 mpg reduction.

Or when going from 10 mpg to 12 mpg is reported as 20% improvement is reported as being equivalent to another vehicle going from 30 mpg to 36 mpg as also a 20% improvement and mistakenly concluding that, as both were 20% improvements in mpg, that they have equal fuel consumption reduction impact. That's right motoring press even % improvements in mpg are not comparable.

I wonder if the 2 or 3 mpg differences once you get into the high 40s, low 50s are sometimes given too much emphasis.