Door opening alerts are designed to warn you of passing traffic so that you don't open a door in its path. These alerts can be provided when the car is stationary or moving very slowly1.
When the car detects traffic that is about to pass close to the car's sides, a light appears in the wing mirror along with a notification in the display. If you begin to open the door on the side of the detected traffic, the alert intensifies. A sound alert can occur along with the visual alerts depending on how urgent the warning is.
Door opening alerts can be turned on or off in settings.
Tip
Door opening alerts and blind spot information
Door opening alerts are indicated in a similar way to alerts about vehicles in your blind spot. These two features also rely on the same rear radars for detection of traffic. However, the features are enabled or disabled independently as they have separate use cases.
Limitations
The car uses its rear radar system to detect approaching traffic. Be sure to read about radar and detection conditions and limitations in their separate section of the manual.