Several years ago, a number of auto manufacturers experimented with electric vehicles. These vehicles were quiet, produced no pollution and had better performance than many gasoline vehicles. However, they suffered from a drawback: limited range and the resultant need for frequent charging.
In the late 1990s, Toyota introduced the Prius, a hybrid gasoline-electric vehicle that uses both a gasoline engine and an electric motor for propulsion. Several other manufacturers followed suit. While each manufacturer controls the drive train a little differently, they all essentially use the electric motor at low speeds and to assist the gas engine at higher speeds. When the electric motor is operating, the car produces little pollution and improves the overall fuel economy of the vehicle. At low speed or during slow stop-and-go driving, the gasoline engine may never come on.
Unlike earlier all-electric vehicles, hybrids recharge their own batteries while coasting and braking. If the battery does discharge, the gas engine continues to provide power for driving and recharging. This means that hybrids do not need to be "plugged in." It also means that they have a much longer range than electric cars.