Like this: https://c8.alamy.com/compde/t0580m/der-verkehr-kurve-spiegel...
Or this: https://cdn-01-artemis.media-brady.com/Assets/ImageRoot/DMEU...
Reasonably common in difficult corners in Germany and Austria. Probably elsewhere too.
The downside is that it's road infrastructure that has to be installed. The upside is that it works for everyone, including people in 20 year old cars or on bicycles.
These are very common in Spain too.
You know what, that’s fair. That’s a good solution.
If it weren’t for the struggles of getting municipal infrastructure installed, I’d prefer it.