Hybrids are just getting started in their life. Look back to how big a cell phone battery was in 1990. The size of a small overnight bag. Now they're smaller than a pack of cards. I think that these hybrid batteries are likely to get better as well so that they can be used for more of the freeway driving, vs. the stop-and-go driving. That's where you see the real difference, when you're stopping every 5 minutes and never get above 35 mph.