[silon42]

I wonder if I should install a popup 30 sign on a rear window for tailgaters in the future.

[psd1]

Good thinking, but try a mirror. The majority of primate species don't recognise their own reflection, and the threat signals they display make them back off.

[yomismoaqui]

But then you have the problem of cleaning the feces from that mirror.

[MaxikCZ]

I hate it here. Please dont change.

[Tade0]

I'm curious as well, but I'm afraid they don't use such systems due to how they also keep distance as well as speed.