D. Onboard Computer
A laptop computer inside the car gathers data from the sensors and controls the vehicle through its own onboard computer systems. This makes the steering wheel appear to turn on its own. Data from each driving session is transferred to Google servers for analysis, which is helpful in fixing bugs.
E. Video Camera
A video camera placed near the rearview mirror detects important visual cues such as changing traffic lights.
F. Manual Control
The red button instantly restores manual control of the car if the standby driver deems it necessary. A person can also grab control by turning the steering wheel slightly or tapping the brake.