Experts: MPG ratings may mislead

Experts: MPG ratings may mislead - Autos- msnbc.com

"A couple drives a 25 mpg sedan. They trade it for a 50 mpg hybrid, a 25 mpg improvement. A family with mom, dad and three kids has a 10 mpg SUV to haul everyone around. They trade it for a 20 mpg station wagon, a 10 mpg improvement. Sounds like the couple did better, at least in miles per gallon.
But lets look at gallons per miles. At 25 mpg the couple burned 400 gallons over a year and their new 50 mpg hybrid cuts that to 200 gallons. They save 200 gallons. At 10 mpg the family’s SUV burns 1,000 gallons of gas a year. At 20 mpg the station wagon burns 500 gallons — they save 500 gallons, much better than the couple."

There's been a push for America to start using the European style of measuring fuel efficiency "litres per 100 km." The idea is that this type of measurement would give buyers a better idea of what they were getting. Using the above example in a "gallons per 100 miles" scenario the couple would see that going from 25 to 50 mpg would save them 2 gallons per 100 miles whereas the family going from 10 to 20 mpg would save 5 gallons per 100 miles.