Ford Motor Co.'s new C-MAX Energi plug-in hybrid has received an Environmental Protection Agency-certified fuel-efficiency rating of 100 miles per gallon equivalent.
The 100 mpge (108 city and 92 highway) tops the Chevrolet Volt, at 98 mpge, and the Toyota Prius Plug-In Hybrid, which gets 95 mpge.
Electricity is not measured in gallons; a conversion factor is used to translate the fuel economy when running on electricity into miles per gallon of gasoline equivalent. The combined mpge estimate includes a mix of gasoline and electric energy use.
Source
The Detroit News