AT meaning in Governmental ?

An automatic transmission (sometimes abbreviated to auto or AT) is a multi-speed transmission used in motor vehicles that does not require any driver input to change forward gears under normal driving conditions. It typically includes a transmission, axle, and differential in one integrated assembly, thus technically becoming a transaxle.

The most common type of automatic transmission is the hydraulic automatic, which uses a planetary gearset, hydraulic controls, and a torque converter. Other types of automatic transmissions include continuously variable transmissions (CVT), automated manual transmissions (AMT), and dual-clutch transmissions (DCT). An electronic automatic transmission (EAT) may also be called an electronically controlled transmission (ECT), or electronic automatic transaxle (EATX).

The 1904 Sturtevant "horseless carriage gearbox" is often considered to be the first true automatic transmission. The first mass-produced automatic transmission is the General Motors Hydramatic three-speed hydraulic automatic (using a fluid coupling instead of a torque converter), which was introduced in 1939.