The reason for two motors is in the strengths and weaknesses of both types. The electric motors use no energy during idle, they turn off. At low speeds, electric use less than gas motors. Gas motors do better at high speeds and can deliver more power for a given motor weight. That means during rush hour stop and go driving, the electric motor works great and, as an added benefit, does not produce any exhaust thus reducing smog levels. At higher speeds above 40 mph, the gas motor kicks in and gives that peppy feel so many car owners look for when driving on the highway.
Another benefit of having the gas motor is it charges the batteries while it 's running. Many an electric car owner has been stranded just out extension cord range of an outlet. Hybrid owners can forget about this annoyance; the gas motors starts automatically when the battery gets low and proceeds to charge the battery. A hybrid no longer needs to be plugged into an outlet. All this new technology comes at a price: a hybrid car is not cheap. With two motors and all the ancillary systems to manage them