How visible would the rear view display be in sunlight?
And dashcams are wide angle, so they aren't as useful for seeing traffic approaching from the rear.
Sunglasses mounted mirrors are perfect for cycling: They work in bright daylight or dim light. A slight turn of my head sweeps the view across a wide angle, but I can still see far back along the road.
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I wonder where a 360 camera or a front & back camera would be mounted to get a good view forward and back without being blocked by the rider?