This document provides an overview of how a hybrid vehicle system works. It explains that a hybrid system combines a gasoline engine and electric motor to maximize the strengths of each. It then describes the different ways the Toyota hybrid system utilizes the electric motor and gasoline engine for various stages of driving: using only the electric motor for starting and low-speed driving; using the gasoline engine as the main power source for cruising; supplementing acceleration with battery power; regenerating energy from braking to recharge the battery; and shutting down both engines at rest to avoid idling waste. The hybrid system aims to improve fuel efficiency and performance.