Don't know the area, but the problem usually is that you see a lot of similar signs in places where it's not needed. So the warning is not very salient. You ha

Don't know the area, but the problem usually is that you see a lot of similar signs in places where it's not needed. So the warning is not very salient. You have to design with human psychology in mind. And the boy that cried wolf is a parable that also holds for traffic signs.