You can also do some interesting things like focus on a specific camera when the situation calls for it. For example, in the image below you can see the two side mirror images. When a turn signal is activated the system could put just the camera on that side into full-screen mode. This would allow the driver to see more on that side of the car.
These systems offer much needed additional information for drivers, but can also be used in accident studies, just like a dash cam to give investigators much needed additional information about the events leading up to an accident.
Source: NY Times