I do not think you understood what I was asking

When the speed limit changes from say 30mph to 40mph the screen flashes with the new speed and also the voice says "you can now increase the speed, limit 40mph"

I am looking for something that does the opposite.

It is specfically the increase the speed part of the skin/ux.
It is NOT speedcams or overspeed warnings

here is screenshot of the thing I am talking about
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