There are three main driving components that drive-by-wire systems typically replace with electronic controls: throttle, brakes, and steering. These systems are typically referred to as electronic throttle control, brake-by-wire, and steer-by-wire.
The most common form of drive-by-wire technology and the easiest to find is electronic throttle control. Unlike traditional throttle controls that couple the gas pedal and throttle with a mechanical cable, these systems use a series of electronic sensors and actuators.
Vehicles with computerized fuel controls have used throttle sensors for decades. These sensors tell the computer the position of the throttle, but the throttle is still activated by a physical cable. In vehicles that use true electronic throttle control (ETC), there is no physical connection between the gas pedal and the throttle. Instead, the gas pedal sends a signal that causes an electromechanical actuator to open the throttle.