Originally Posted by
chephy
How can you tell? Signs tend to be positioned so they're visible to the driver on the road to which they apply, not to drivers on crossing roads.
That is exactly why stop and give-way signs have unique shape - so they can be identified even by the driver on the main road. Stop sign has hexagonal shape, while yield sign has a reversed triangle shape. No other traffic signs are shaped that way.
In practice, sometimes, drivers on the main road have also a sign giving them right of way, but not always. Our law states that in situations where (this is a bit tongue in cheek) lower speed and caution from drivers on the main road is required, a sign giving them right of way is deliberately omitted, forcing them to slow down and check the signs on the road they are crossing.
Originally Posted by
chephy
Their placement, at least in North America, is not standardized.
In North America, in my experience, most roads have some sort of signage. So if the street I am on has no stop sign, I assume the crossing street does. I don't go out of my way looking for it.
I don't know about laws in the USA, but in Europe, if you don't have a right of way sign, you need to check the street you are crossing. If it doesn't have a stop/yield sign, you need to give the vehicles on your right the right of way.