Very good news is that gas mileage on our first two tanks of gas in our Toyota Highlander Hybrid is 28.7 mpg, better than advertised although obviously not as good as we could get with many smaller conventional cars. We do hilly country driving, Interstates and two lane highways mainly with a little bit of "city" driving in Burlington, population 40,000.
The very graphic display of instantaneous gas mileage and whether the car is running on gas alone, gas plus electric, electric alone, or recharging probably influences our driving behavior; we can see the penalty for sudden acceleration clearly. While Mary's driving, I try to figure out its algorithm for what combination of motive power to use but haven't cracked it yet. The battery never gets very low which makes me think we may be squandering some recharging opportunities by not using enough electricity to free-up capacity to use more charge. Probably won't try to reprogram it though.
Interesting problem with hybrids is that they don't make any noise when they're running all electric, which they frequently do at low speed. So bicyclists, pedestrians, joggers, and dogs don't know we're behind them – especially when they're iPod equipped. Beeping seems a little rude in these circumstances. Electric cars need a pseudo engine noise generator to be turned on when it's important for them to politely make their presence known. Of course it would be turned off while sneaking home late at night.
Why we bought the Highlander is here.