Along the road from us are two of those sped indicators that clock your speed and advise you to slow down.
I didn't see the point after encountering my first one years ago in a village outside of Northampton and still don't now.
The daft lads and lasses treat them with contempt and anyone 'driving' a German bragwagon, barrelling through at Mach/ warp speed, obviously think such things don't apply to them, ever.
The arrogant driver doesn't care, they being the one who causes the problem in the first place.