Quote:
Originally Posted by sheepdog 44
The question is would you get better mileage if your commute was level? 44.5mpg round trip is pretty good. Sorta like pulse and gliding the terrain.
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Too bad fuel economy doesn't work that way. You can't average the averages. 14 mpg one way and 75 mpg the other way does not give 44.5 mpg
i.e.
(14+75)/2=44.5 is the WRONG way to do it
In actuality, you have to divide the total miles driven by the total number of gallons used to find the average.
i.e.
Gas used on the trip there:
(15 miles/14 mpg)= 1.071 gallons used
Gas used on the trip back:
(15 miles/75 mpg)= 0.200 gallons used
Overall gas mileage:
(30 miles travelled)/(1.071 gallons + 0.200 gallons) =
23.6 mpg
Quite a bit of difference.
Which brings an interesting point: This shows that having a large elevation change that significantly affects gas mileage actually does hurt pretty significantly over the round trip when compared to no elevation change. You may get great numbers one way, but overall the fuel economy suffers.
Sorry about rambling on. I'm quite a math nazi, and this is one of my pet peeves.
