Why are hybrid cars so efficient?
Hybrid cars are known as hybrids because they use an electric motor to augment the performance of a small, efficient gasoline engine. But this isn't the only reason hybrids are more efficient than gas-powered cars. Hybrid cars are made of lightweight materials, so they require less energy to accelerate or drive up a hill.
Some hybrids rely on a process known as regenerative braking to recharge their batteries. When you brake, you remove energy from your car, which normally just dissipates in the form of heat. In some hybrids, though, the electric motor is used to slow down the car, at which time it also acts as a generator so it can divert some of that energy back to the batteries.
And instead of idling, the gas engine turns itself off, and you get power from the electric motor and batteries. Also, hybrid cars' aerodynamic design and special tires reduce both air drag and drag against pavement, which also increases efficiency.