Most mandatory road signs are circular
because they are mandatory signs
Mandatory symbols
WHAT icons? If you are referring to the SHAPE of the signs themselves, the shape of the sign itself signifies the type of information the sign conveys. (e.g.: Octagaonal signs are ALWAYS stop signs - Diamond-shape signs ALWAYS convey some type of warning message - etc).
a triangle
I'm pretty positive Diamond shapes signs are warning signs.
weight, size, Shape, height, state, matter
circles
boobies
Yes, stop signs are octagonal in shape.
In North America, they're round.
Simply the same as the stop signs in America, an octagon.
Octagon just like the stop signs on the road