One of the interesting things that has come out of the Prius experience is how it affects the way people drive. The Prius has a computerized display that estimates your mileage and shows when you are using energy (red) and when you are coasting or regenerating (green). From what I gather, it's sort of like a video game. With this feedback drivers soon learn to go slower and avoid hard acceleration or braking. Some have compared this to brainwashing. I wouldn't go that far, since brainwashing implies something being done against your will. Your Prius owner presumably bought the car for efficiency, so they've already paid their tuition for this lesson. Yet, it does underscore some of the limitations of a conventional, non-plug-in hybrid. There's nothing magical about the hybrid power plant, it's simply efficient because the gasoline engine isn't running all the time. An early hybrid researcher once calculated they could achive similar efficiency by simply using two gasoline engines, and turning one of them on and off as needed. Some modern V8 engines use a similar scheme of running on only four cylinders part of the time, although that doesn't gain a lot since it leaves them with the full mechanical friction and pumping losses of all eight cylinders. (It might be more promising to have a small engine with a supercharger that can be switched on or off.) So, here's the Prius delivering good fuel economy, but getting the most out of it requires training your driving habits with the help of the computer -- and the lessons learned could apply to most vehicles, hybrid or otherwise. You also have to ask yourself, do we really all want to drive like grandma? Is that what we've all signed up for? As for the Tesla Roadster, we've been told it's good for about 200 miles of typical sports car driving, or 250 miles of driving like grandma in her Prius. How will you drive yours? ???