In an effort to improve fuel economy, drivability, durability, and cost, many changes have occurred to automatic transmissions over time. In the last decade however, the proliferation of new models has been unending. Step-type transmissions have ratcheted up the gearing from old-time three- and four-speeds to five- through seven-speeds.
A parallel hybrid vehicle allows the power from a gasoline engine and an electric motor to drive the vehicle independently or in conjunction with one another. The Toyota Prius has such a design as well as the Honda Insight and the Civic Hybrid. Although they are all parallel hybrids, there are differing operational strategies between Toyota and Honda.