I believe it's a triangle
Bump
A yield sign.
yellow diamond, with a arrow blinding to the left
A triangular road sign warns of an upcoming hazard such as a flood or hidden dip in the road.
Advisory speed sign
The Dip sign warns a driver that the road has a sudden drop in elevation
Advisory speed sign.
Yellow diamond, with a curving arrow.
Yellow diamond, with a curving arrow.
A yellow diamond-shaped sign with a black number inside indicates the highest safe speed limit in that area.
alerts, warns, admonition, counsels, forewarning, hints, omen, sign, tip-off
That is correct but it is also the color. The shape of a sign is to warn people that are maybe colored blind and can't see the "red" stop sign. So they know it a stop sign because of the 8 sides on it. Hope it helps.