Probably should mention that hybrids do more than just supplement a small petrol engine with an electric flywheel motor to improve efficiency. Both the Insight and the Prius use carefully chosen materials to save weight and a "fastback" body to improve aerodynamic efficiency. All hybrids can switch automatically to electric power only at steady speeds over short distances, use engine stop-start technology (which seems to confuse people even though it's been around longer than hybrid technology?!), use low energy tires and supplement the resulting loss of grip with electronic driver aids and (& this one really confuses people..) efficiency oriented climate control which both prevents over use of the fans & AC but also creates a more relaxed, comfortable driving environment, which is conducive to a more relaxed and economical driving style.
On that last measure, you'd be surprised just how much difference psychology makes. I've already covered the clever instrumentation in the Insight on another thread, but if you draw on your own experiences you know that drivers who are hot, cold and/or sat in a humid car are PO'd at being there and tend to drive more aggressively because they just want to get where they're going and get out. Making the driving environment a nice place to be encourages drivers to sit back and relax, even in traffic and that encourages people to take it easy rather than ramming the accelerator in to the carpet at every opportunity.
On that last measure, you'd be surprised just how much difference psychology makes. I've already covered the clever instrumentation in the Insight on another thread, but if you draw on your own experiences you know that drivers who are hot, cold and/or sat in a humid car are PO'd at being there and tend to drive more aggressively because they just want to get where they're going and get out. Making the driving environment a nice place to be encourages drivers to sit back and relax, even in traffic and that encourages people to take it easy rather than ramming the accelerator in to the carpet at every opportunity.