If the volt is predicted to get 50 mpg when operating in it's range extender mode, why don't we have more vehicles made like that without the battery aspect? Locomotives have been doing it for a long time. This is OLD technology, but was never implemented into cars. Why don't we have cars that are purely electric drive with an ice/gen combo to power the whole thing. Weight and cost would be reduced with no battery to muck around with. I wondered about this several years ago. Most hybrids use the engine as part of the drivetrain and a motor to suplement it, correct?