Hybrids such as Toyota's Prius have become a common sight. Now major automakers are proposing a next generation of hybrids that can be plugged in to extend their electric range and vastly improve fuel economy. This interactive graphic shows how conventional hybrids work, as well as how two versions of these proposed plug-in hybrids, one labeled "Plug-in Hybrid" and the other "Extended-Range Electric," work. Each of these plug-in hybrids operates differently when the battery is charged versus when it is largely depleted. Click on one of the five buttons above to view animations of how the vehicles operate under different driving conditions. Each vehicle operates during a stylized drive cycle, starting at low speeds, accelerating to highway speeds, and then decelerating to a stop. If at any time you'd like to pause the animation or select a different part of the drive cycle, click on the appropriate section of the graph at the bottom right of the graphic.
Read in full and go to interactive primer - 'Electric Cars Primer'