How do automatic cars work?

An automatic car works by using an automatic transmission coupled to a torque converter. The transmission shifts based on the speed of the vehicle by using electronic and hydraulic systems. Some automatic cars provide a manual override feature for increased driver input.
Features

An automatic transmission can include several modes of operation. Park and neutral are used when the car is stopped, and reverse and drive are used to move the vehicle. Automatic cars also include override features that permit the vehicle to be locked in a particular gear when necessary.
Benefits

Automatic transmissions allow drivers to focus on the road ahead rather than shifting manually. Automatic transmissions also prevent drivers from choosing the wrong gear or stalling accidentally.
Identification

An automatic car can be identified by looking on the steering column or center console. If the gear shifter includes indications for park and drive gears, it is an automatic. Automatics also have only two pedals: gas and brake, while a manual car includes a third: the clutch.
History

Automatic cars have been built since the 1950s, and the ease of driving an automatic has propelled automatic cars to popularity, especially in the United States.
Considerations

Although automatic transmissions are easier to drive than manual cars, this is at the expense of higher maintenance costs. Automatic cars include transmission filters that must be changed per the manufacturer's recommendations.