Other than trucks blinking left or right, all of these are pretty common in the US.

As someone who grew up in a rural area, honking before going around turns on small roads or crossing single-lane bridges you couldn’t see the other side of was something we did regularly to avoid being hit.

I don’t experience this as much in larger cities though.

In Sicily in narrow crossings where you don't have the right of way but cannot see you can slowly inch forward, and if someone is around the corner they will honk at you to let you know to wait.

> As someone who grew up in a rural area, honking before going around turns on small roads or crossing single-lane bridges you couldn’t see the other side of was something we did regularly to avoid being hit.

I've never found this in rural Indiana, but I wish it were common practice. I've found people often simply assume no one is coming because there are so few cars on the back roads; very nearly experienced a head-on collision approaching one curve a few years ago.

My father said honking is common going around corners on small roads in the mountains in Columbia.

I don't see those signage on cars in the USA, but there are a few places where cars are explicitly told to blow their horn, example: https://goo.gl/maps/WWC4ACVRdeyUQnZ57