Americans don't do yield signs very well except in the most obvious situations that shouldn't even need yield signs, like highway on ramps, and intersections with islands creating curved right turn lanes. Americans barely have competency at four way stops, the main way who goes next is figured out is someone launching from a rolling stop before the others. There's also often hand waiving, honking, and lights flashing because people are just plain ignorant the actual law, or even common sense.
And traffic circles? Fuck that's super confusing! Americans would rather get into accidents at a four way stop than be confused in a traffic circle. That's why traffic circles are so uncommon.
I’ve personally rarely encountered issues with yielding. Four-way stops are another issue, and any driver in the U.S. has probably encountered them, but they’re solveable issues with basic driver courtesy. They assume basic understanding and cognizance to prevent incidents, but nothing more is strictly required.
The greatest number of accidents I’ve seen have been at stop lights rather than stop signs, weirdly. Driver apprehension and cautiousness at four-way stops may actually prevent more incidents than other systems.
I encounter problems with yielding nearly every day, but I think it has more to do with road design. The yield is on a very long acceleration ramp and it is placed towards the front of the ramp. Then there is a merge sign near the end of the ramp.
I think the idea is that you should yield and only go when it is clear. But because of the length of the ramp, I think they are legally required to have a merge sign there. Invariably people fail to yield, and, since it is uphill, 'merge' into 45 mph traffic at 20 mph. And by merge I mean they just drive on and expect people to stay out of their way.
I have way more problems with people turning on red at the worst possible moment (despite lots of previous safe opportunities) than I do with yield signs though. But I don't doubt the GP's experience either. Drivers are very different in different states and regions of the U.S.
And traffic circles? Fuck that's super confusing! Americans would rather get into accidents at a four way stop than be confused in a traffic circle. That's why traffic circles are so uncommon.