56 MPGe means that a vehicle can travel 56 miles on the energy equivalent of one gallon of gasoline, which is approximately 33.7 kilowatt-hours (kWh) of electricity.
In other words, if a plug-in hybrid or electric vehicle has a rating of 56 MPGe, it is estimated to travel 56 miles using 33.7 kWh of electrical energy from the battery. This metric helps consumers compare the energy efficiency of electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) to that of gasoline-powered vehicles. While MPGe provides a useful benchmark, it's also crucial to consider the actual range of the vehicle when making a purchase decision.