[belZaah]

Radars do this better. They can warn you from much further away and do not require for you to keep an eye out - there’s audible cues.

[SequoiaHope]

Do they also show bikes? I use the mirror not just to monitor cars but see where my friends are. If a friend breaks down and is on the side of the road I want to see without having to fully turn my head around.