Hybrid vehicles use both an internal combustion engine and an electric motor to power the vehicle. Power for the motor is gained by converting energy from the engine and braking into electricity. That electricity is stored in the battery until it is needed, so there is no need to plug the vehicle into an outlet to sustain a charge.

There are different flavors of hybrid techology available that determine the how the motor and engine are used: full-hybrid, mild hybrid, and stop/start hybrid.

A full-hybrid vehicle uses the electric motor to power propulsion in low speeds, as used in driving in reverse or in stop-and-go traffic. At cruising speeds, the gasoline engine will be the primary source of movement, and the electric motor will assist when extra power is needed. The engine will shut down while the vehicle is at rest so that energy is not wasted during ilding. Meanwhile, the car's battery will continue to power auxiliary systems like the air conditioning and stereo. Toyota and Ford vehicles are considered full-hybrids.

By contrast, a mild-hybrid vehicle uses the gasoline engine at all speeds. If the mild-hybrid vehicle has an Integrated Motor Assist (IMA) system, which is used in Honda hybrids, the electric motor will assist in the vehicle's propulsion when additional power is needed. Like the full-hybrid vehicle, the mild-hybrid's engine will shut down when the vehicle is stopped.

A stop/start hybrid does not use the electric motor to aid in propulsion. The motor is used only to shut the engine down when the vehicle is stopped and restart the engine once the gas pedal is applied. This type of hybrid system is used in GM trucks. (4, hybridcars.com)