Cars in the US have to follow EPA testing methods, and those are the only numbers a seller is allowed to use.
The standard has changed several times over the years, most notably in 2008. Prior to this, the tests were “best case”, and were almost impossible to get in the real world. Since then, the tests have become much more “typical use”, including factors like air conditioning, high speed (80mph) driving, cold engine, and cold weather. These significantly reduced the published numbers vs previous years.
I could easily see a car rated for 27mpg in the 2008 test also getting 41mpg+ in the 2007 test.
Cars in the US have to follow EPA testing methods, and those are the only numbers a seller is allowed to use.
The standard has changed several times over the years, most notably in 2008. Prior to this, the tests were “best case”, and were almost impossible to get in the real world. Since then, the tests have become much more “typical use”, including factors like air conditioning, high speed (80mph) driving, cold engine, and cold weather. These significantly reduced the published numbers vs previous years.
I could easily see a car rated for 27mpg in the 2008 test also getting 41mpg+ in the 2007 test.