TIME warns that your gas may not go as far as you expect in some vehicles…

In the grand scheme, 37 mpg is pretty decent—except when you purchase a vehicle that promises mileage that’s 10 mpg better. Two Ford hybrids, the Fusion Hybrid SE and the C-Max SE, boast overall ratings of 47 mpg on their windows in new-car dealerships. Yet a new Consumer Reports study indicates that these mileage claims are way overblown.

Hybrid vehicles are more guilty of inflated figures that others, the story says.