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151,178,588 mi · 110,613 tanks · 7,501 cars · 1 database
Mileage Database FAQ
In version 1 I used the mileage override feature. Does this still exist?
How do GreenHybrid's mileage estimates differ from those of the US Environmental Protection Agency?
EPA estimates are made under ideal controlled circumstances and do not reflect the true driving habits of American consumers. As automobiles have evolved, the EPA has not adjusted its test to consider speed limit increases, air conditioning, technological evolution and other factors.
GreenHybrid's Real Hybrid Mileage Database gathers actual fuel economy records from people like you. As opposed to the EPA, GreenHybrid's system inherently includes changes in driving psychology, temperature, environment and other variables that affect one's fuel economy. As a result, GreenHybrid provides a more accurate tool to reflect and predict the mileage of consumers.
The figures provided here are not meant for direct comparison to EPA estimates for hybrids or non-hybrids.
Are cars with farther distances logged given additional weight in calculations than cars with smaller distances?
No. Weighting cars based on distance builds on the premise that after driving far enough, every car will achieve the same fuel economy. Therefore, cars with more miles are more "accurate." This, however, is an incorrect assumption. There is such a large quantity of variables that contribute to one's resultant fuel economy that no single value can be considered most "accurate." To best reflect the conditions of a typical driver, a person with ideal conditions is given equal consideration as someone with unideal conditions, even if they have not necessarily contributed an equivalent distance. Also, the median of the sample is used to reduce the influence of outliers.
Should I expect to match the median fuel economy figure displayed on the main database graph?
Not at all. In fact, very few drivers actually get the exact number displayed on the main graph. Instead, one should concentrate mostly on the middle 50% values, visualized by a black line. Half of all drivers of the respective hybrids fall somewhere in this range, so it's likely that you may, as well. Remember that there is a large number of variables that determines one's fuel economy and your circumstances may result in a number much higher or lower than the average.
May I reference GreenHybrid's mileage figures in my publication or website?
One of the best ways to promote hybrid technology is to spread the word and counter misinformation. Feel free to discuss the Real Hybrid Mileage Database's analysis with everyone. Be sure to mention the online community that makes this site such an informative resource.
My Ford Escape Hybrid or Toyota Highlander Hybrid was visible on version 1 of the database, but I now see on the Manage My Cars page that it has been deactivated. What's wrong?
In order to increase the accuracy of GreenHybrid's mileage figures, the 2-wheel and 4-wheel drive versions of these models were separated. Affected members are required to specify 2WD or 4WD by editing their car before it will display in version 2 of the database.
Well, no. But, that's a good thing! Version 2 of the Real Hybrid Mileage Database is now capable of using distance and fuel economy figures as starting points while including additional tanks in your calculations. If you used to have a "mileage override," it has been converted into a starting point.