How does it work under poor lighting conditions?
That's the time when many collisions happen, specifically because of the poor lighting, especially when it's low-contrast, like twilight conditions, pre-dawn, covered parking areas, under bridges / in tunnels, darkly cloudy days, rain / snow / dust storms etc?
What exactly does it do? Meaning, what kinds of hazards is it looking for, and where?
Most of the phones/etc I've seen pictures from are not very wide-angle. People have a better wide-angle vision than the cameras do, so unless there's some sort of hardware to go with it that helps widen the camera's lens angle, and then have the software deal with the distortion as necessary, the rider should have a much better view than the app/hardware does.
Exactly how is it warning the rider?
Is it *only* sound? Or is there any visual component? (does it display anything on the screen of the device at all?)
If it is a visual warning, or it has any display on screen, then it's actually a hazard itself, because it is taking the rider's eyes and attention and focus away from the things that should be focused on.
You *never* want to visually distract a rider (or driver, pedestrian, etc) from the situation they're presently in, as it takes too much time for them to re-focus on the situation again, and then to react to it.
