A Hybrid Electric Vehicle (HEV) combines a traditional internal combustion engine with an electric motor. This design allows the vehicle to use both gasoline and electricity, improving fuel efficiency and reducing emissions. The electric motor can assist the engine during acceleration and can also power the vehicle at low speeds, making it more environmentally friendly. HEVs typically use a battery that is charged through regenerative braking, which captures energy usually lost during braking. This means that the vehicle can recharge its battery while driving, eliminating the need for external charging stations. Popular examples of HEVs include the Toyota Prius and Honda Insight.