Saw a report some time ago about Hybrids and basically, if you drive under 80 miles at a time (the range of a fully charged battery pack), then you're fine. As soon as you cross that threshhold, and the engine has to kick in, then you start tapping into your fuel supply. Hence, when you see Hybrids doing cross country trips, they're no better off for the most part than any normal car. That's where stuff like the regenerative generator technology comes in. If they add in features like that, the batteries are also charged by the vehicle slowing down, instead of needing to start the engine. It won't totally do away with the need for the engine, but if you add it to a hybrid and do a lot of stop and go traffic, it will greatly reduce the amount of engine use and the consumption rates...
