An automatic transmission is a type of vehicle transmission that automatically changes the gear ratios as the vehicle moves, allowing the driver to focus on steering and acceleration without needing to manually shift gears. This system uses a complex arrangement of gears, hydraulic systems, and electronic controls to optimize engine performance and fuel efficiency. Unlike manual transmissions, which require the driver to engage the clutch and select gears, automatic transmissions simplify driving by using a torque converter to manage power transfer. This makes them popular in many modern vehicles, providing a smoother driving experience, especially in stop-and-go traffic.